Wildguzzi.com
General Category => General Discussion => Topic started by: brider on December 02, 2023, 09:28:33 PM
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This is a follow-up to my recent rotor-removal thread. I got the front cover off, measured a few things, but the real problem (it's a Cal 2 auto, pulled it off the road because the dreaded auto-slip began again suddenly) looks like the pump impeller (?) is worn and rounded and oversized to the "6 mm" hex shaft to the point that it needs to be replaced or have the shaft welded in place.
The shaft didn't look too bad, engagement length looked adequate and the edges didn't look too rounded:
(https://i.ibb.co/tJ7wkYH/20231202-201004.jpg) (https://ibb.co/tJ7wkYH)
To my surprise, it measured under 6mm, but so did every other 6mm hex wrench I had:
(https://i.ibb.co/djTqJQq/20231202-201028.jpg) (https://ibb.co/djTqJQq)
For future reference in case I want to have a 1/4" hex surface-ground down to a better fit, a 1/4" hex measured slightly over 6.2 mm:
(https://i.ibb.co/Wy8bF2T/20231202-201419.jpg) (https://ibb.co/Wy8bF2T)
host an image (https://imgbb.com/)
As best I could measure, the cam hex measured slightly over 6 mm:
(https://i.ibb.co/QnpCYM6/20231202-201702.jpg) (https://ibb.co/QnpCYM6)
But here's the ugly part: The pump impeller looks really sloppy and worn, and the smallest measurement I could get by rotating the caliper on-axis with light pressure on the thumb wheel was about 6.40 mm, way too sloppy for the 5.90 mm shaft:
Oops, image loader is "down for maintenance", but suffice it to say the pump hex interface is worn beyond useability.
Opinions on how to proceed? What are the chances of finding a non-worn (or as badly-worn) replacement in someone's garage stash?
If I WERE to find one, the idea of a custom shaft ground down to different sizes for the cam-end and pump-end doesn't sound like such a hair-brained idea.
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I might have one still in a timing cover hanging in my garage stash.. I’ll look for it tomorrow.. if it’s there you can have it for free.
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That is what I did as my convert was worn more in the pump than the cam so machined a hex with two different ends just so long as there is a little wiggle room for alignment/ expansion but why so much wear, when I acquired my convert it was pumping 55 odd psi hot double the recommended spec which would have been placing a lot of stress on that hex , Check your pump pressure , I think the book says 28psi . I had a master gauge on mine for a while and the pressure climbs high when cold so the first 5 minutes of the ride keep the revs down and be kind to the pump drive. Ray
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If buying a used pump, be aware there are two different "socket" depths. On early pumps the socket was only 8 mm deep, on later pumps this was increased around 12 mm.
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This is very interesting to me. :popcorn:I ride my convert in very remote areas where there is no cell service, and its always on the back of my mind, as I am pretty sure I have sorted all the other little issues that may leave you stranded. It would be nice if we could get some sort of coupler machined to sort this slipping hex problem, once and for all. Brider, have you thought about adding a pressure gauge to your Cal II auto? A forum member that is very knowledgable on converts, recommends it ,and I have been thinking of adding a pressure gauge to my convert. I believe it only has to be plumbed in to the pressure line where it enters the bellhousing. I think its the upper hose. I just need to find a nice small pressure gauge and a location to mount it.
Rick D,
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Here you can get the idea, the pump has been rounded and the fit is sloppy with the 5.9 mm hex shaft, I'm positive this is where the slipping is occurring:
(https://i.ibb.co/t8dTd1P/Cropped-ATF-pump.jpg) (https://ibb.co/t8dTd1P)
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I might have one still in a timing cover hanging in my garage stash.. I’ll look for it tomorrow.. if it’s there you can have it for free.
Awfully nice of you, thanks.
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Here you can get the idea, the pump has been rounded and the fit is sloppy with the 5.9 mm hex shaft, I'm positive this is where the slipping is occurring:
(https://i.ibb.co/t8dTd1P/Cropped-ATF-pump.jpg) (https://ibb.co/t8dTd1P)
IIRC, Guzziology has a section about the coupler part of the pump being improperly heat treated, with that being the result.
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This is very interesting to me. :popcorn: It would be nice if we could get some sort of coupler machined to sort this slipping hex problem, once and for all. Brider, have you thought about adding a pressure gauge to your Cal II auto? A forum member that is very knowledgable on converts, recommends it ,and I have been thinking of adding a pressure gauge to my convert. I believe it only has to be plumbed in to the pressure line where it enters the bellhousing. I think its the upper hose. I just need to find a nice small pressure gauge and a location to mount it.
Rick D,
Can you adjust the pressure on this pump? Is the gauge to just monitor pressure, no more no less?
For accuracy you want the spec pressure to fall midway on the gauge scale (read 25 PSI, use 50 PSI gauge) One post said it was reading 55 PSI so maybe a gauge of 75 PSI to protect it from spikes. Use a glycerin dampened gauge.
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IIRC, Guzziology has a section about the coupler part of the pump being improperly heat treated, with that being the result.
I remember reading that, yes, but I don't recall what the fix was? Did the factory eventually begin supplying properly heat-treated parts? I would've guessed by '85, any remaining stock they had to build Cal 2 Autos would have the heat-treating problems solved.
I also don't recall a lot of discussion in these pages about non-heat-treated pumps....seems like the only solution would be to heat-treat a new replacement, and damage would've already been done to a non-heat treated part.
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There is a pressure relief valve, i believe in the front cover by the pump. It has a spring and shims, where I bet the pressure can be adjusted, by changing the shimming. the pressure gauge would show a drop in pressure, if the couple starts slipping, before overheating the TC. The gauge would also show if the pressure were high when the fluid is cold, etc, like mentioned above.
Rick D.
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I'm going to review the pressure-guage installation on these pages and in my e-mail/PM history. I've talked off-line with some of the Convert gurus in the past, and a guage sounds like a good idea "just because", but also a temp guage would come in handy, and I'm sure there are digital varieties that will display both.
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There is a pressure relief valve, i believe in the front cover by the pump. It has a spring and shims, where I bet the pressure can be adjusted, by changing the shimming. the pressure gauge would show a drop in pressure, if the couple starts slipping, before overheating the TC. The gauge would also show if the pressure were high when the fluid is cold, etc, like mentioned above.
Rick D.
Changing shims on the relief spring would definitely change the pressure (adding shims would increase pressure). Sounds like a pain to access though.
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I never had any issues with the hex on my 84 Cal II auto. I took it apart for inspection, and everything fit nicely, so I just replaced the seal and O ring,and it worked for 46K miles until I sold the bike. That bike served duty as a tug for a good sized sidecar, a Texas Ranger, so that pump coupling worked hard. It must have been the newer ,improved version, although I never measured the coupler depth. My current convert is a 76 that I got with only 10K miles, and sat unridden for many years, so I think it may have the earlier version.
Rick.
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Changing shims on the relief spring would definitely change the pressure (adding shims would increase pressure). Sounds like a pain to access though.
It may not be too bad to access, if I remember correctly, its on the top front part of the front cover. Removing the oil cooler, may give enough space to get to the relief valve plug.
Rick.
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Awfully nice of you, thanks.
darn, I have a timing cover but the pump parts have already been removed. So the OP still needs one.
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I never had any issues with the hex on my 84 Cal II auto.
I don't know if my problems are of my own making (backfiring history), but I am mad at the bike for making me deal with this pump thing so many times in it's limited mileage. Irrational, I know, but sometimes I am just so DONE with this thing.
OK, enough whining. Glad I have another bike to ride.
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gauge adapter I installed on my convert, you will need a longer banjo bolt.adjusting pressure is delicate and by turning the spring end to end altered my pressure 5 or so pounds as the circumference/diameter of the spring being massed produced is different each end and allows the ball to sit deeper in one end etc , it takes very little to alter pressure so if some one has had it to bits and flipped the spring theres a good chance pressure has moved, you may have to gently file the internal circumference of the spring to allow the ball to sit in that tiny fraction further Ray
(https://i.ibb.co/r7Mj4b5/gauge-adapter.jpg) (https://ibb.co/r7Mj4b5)
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no 1 the only thing the oil pump, the main thing the oil pump on a convert is to cool the oil pump thruogh the cooler , cool the tourk conveter the convert allways slips never locks up. So you could edm a larger hex in the cam and pump rotter , how ever that will get it running but i also think the cause is misalingment of pump and cam tricky indicating that in but that is why some go many beeeg miles and others not so. the pump router is orbiting.
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some go many beeeg miles and others not so.
This sounds like it makes sense. Manufacturing tolerances all gone the wrong way.
For anyone interested, here's a pic of the "old style" short-engagement pump Charlie mentioned. I actually had this cover in my pile, hex looks much better than my "later" style:
(https://i.ibb.co/cFKBtSV/20231203-161156.jpg) (https://ibb.co/cFKBtSV)
My "later" style:
(https://i.ibb.co/BtrsgZy/20231203-161203.jpg) (https://ibb.co/BtrsgZy)
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First off I’m not at all familiar with the hex drive on this pump other than what I see in the pics.
Here’s a big but and based entirely on looking at the pics in this thread. Can you cut a 6mm 6 point socket to length and interference grind the OD to press into the pump section to increase the hex contact area or is that open area for another component?
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The "old style" one pictured has a circlip holding the seal in? I dont recall any circlip on my 76, when I was in there, to replace the seal ,and O ring.
Rick.
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I dug up some old e-mails I exchanged with Rodekyl on this subject, he actually welded a hex shaft to a pump coupler (I've been calling it an impeller) for a road-side repair and it lasted him for a few cross-country trips, in fact it never failed, even with any mis-alignment to the cam. Tempting to consider.
He also mentioned EDM-ing a larger hex (as someone in this discussion also mentioned) into the coupler and then grinding a custom hex shaft to fit, I think as of today that will be my #1 plan until/unless I find an almost pristine replacement pump. I am not at all familiar with the EDM process, so I need to do some internet education. And then find someone local who may do it.
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i have not opened up my project convert yet...(so i may be talking out my arse) but i am assuming that the pump is driven by then hex shaft from the end of the cam ?
It seems weird to me that the pump has the hex so deep and short in the input shaft. also from the photos provided here, heat treating on the pump end of things is looking suspect.. (new design)
I think that turning a length steel equal the the c' bore above the pump hex. and then having a hex broached through it and then hardening it. pressing it into the pump c'bore using the hex shaft as an alignment guide. once pressed into place, a couple of tig beads at the end to secure it would rectify this issue.
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Keep in mind this is a situation without perfect alignment. Reducing flexibility of the alignment in the moving parts may not be helpful. I think Rodekyl used an electric pump on his trike project to overcome this issue. His project was documented here, maybe a search would turn it up.
Brian
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I think that turning a length steel equal the the c' bore above the pump hex. and then having a hex broached through it and then hardening it. pressing it into the pump c'bore ....
I think this idea has merit, but would reduce the shaft length to a very short shaft. Not sure if that's good or bad. And has been mentioned, welding eliminates any mis-alignment forgiveness; maybe Rodekyl had almost perfect alignment from the factory on his roadside repair. Can't count on that, though (although I won't eliminate that solution).
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i think the pump is called a tyycoid gear pump , any way i beleive it is made of powderd metal you absolutly need to verify alingment do what it takes to get in alingment burn larger hex 1/4 in should clean it up and install new alingment dowls so the next time the case is removed it will cime back in alingment. tool maker i knew had a bmw brand motorcycle r90s input shaft wore splines on input shaft wore off 8000 miles replaced it same thing then welded up ground larger type spline made same for clutch 2 times . i told him the alingment douls arre off put engine and trans on mill table dial it in turn up oversize alingment douls , but being then bullhead he was no it was very painfull to see. oh he did finaly cure it he sold it. i also said take the douls out and snug the bell houaing bolts and rev a few times it seak alingment, at lealt it would not be forsed out bu=y misalinged pins.
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Just get a larger inch size allen wrench and grind it to size on both ends. With a precision grinder it would be easy, but could even be done carefully with a dremel.
If you're still concerned about the fit in the rotor (gaps) even though fitting snugly, use a bit of loctite bearing epoxy.
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Just get a larger inch size allen wrench and grind it to size on both ends. With a precision grinder it would be easy, but could even be done carefully with a dremel.
If you're still concerned about the fit in the rotor (gaps) even though fitting snugly, use a bit of loctite bearing epoxy.
If you read the previous posts you'll see that's been discussed. But, that's not going to be enough for brider's rounded out coupler. I don't think using any sort of epoxy is a good idea as the drive piece needs to be able to move slightly to allow for any misalignment between the cam and pump.
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Can a new coupler be machined by someone with tool and dye knowledge and the proper equipment? I hate the thought of our beloved Converts being "dead in the water" because of a failed couple that is NLA.
Rick.
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Can a new coupler be machined by someone with tool and dye knowledge and the proper equipment? I hate the thought of our beloved Converts being "dead in the water" because of a failed couple that is NLA.
Rick.
I'm sure it can. I posted this response in brider's wanted ad: "I've sent a message to a machinist friend to see if he could reproduce the coupler with the deep socket, broached to the correct size, and heat treated properly. I'll let you know when I hear back from him."
Edit: Heard back from him just now. I'll be sending more detailed photos and dimensions to him this evening. For this to be economical, a small batch would need to be made.
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i think the pump is called a tyycoid gear pump
https://pumpschool.com/principles/gerotor.php
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Hey Charlie, Thats great! Maybe if a group of us Convert owners get together on this we can get a batch made up, at a reasonable price. I sure would be interested. I am pretty sure I will have a convert in my garage, as long as I am riding. It has pretty much become my "go to" bike for everyday use.
Rick.
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https://pumpschool.com/principles/gerotor.php
Good information RE; gerotor pumps. Simple and appropriate for the application. I guess Luigi, did it right.....except for this one little pump drive bit,that needs improving. :laugh:
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Here's the pertinent page from Guzziology:
(https://i.ibb.co/jkhsmhh/Guzziology-Convert-pump-issues.jpg) (https://ibb.co/jkhsmhh)
For anyone interested, here's some photos of the coupler, complete pump and a crude drawing with dimensions. Sent all of these to the machinist.
(https://i.ibb.co/30vr3p8/Jeff-s-Le-Mans-engine-Convert-ATF-pump-025.jpg) (https://ibb.co/30vr3p8) (https://i.ibb.co/52F3PMY/Jeff-s-Le-Mans-engine-Convert-ATF-pump-028.jpg) (https://ibb.co/52F3PMY) (https://i.ibb.co/s6p4M48/Jeff-s-Le-Mans-engine-Convert-ATF-pump-031.jpg) (https://ibb.co/s6p4M48) (https://i.ibb.co/3kjHjY2/Jeff-s-Le-Mans-engine-Convert-ATF-pump-034.jpg) (https://ibb.co/3kjHjY2) (https://i.ibb.co/Z2BByDx/Jeff-s-Le-Mans-engine-Convert-ATF-pump-035.jpg) (https://ibb.co/Z2BByDx) (https://i.ibb.co/7Xs3qH7/Jeff-s-Le-Mans-engine-Convert-ATF-pump-036.jpg) (https://ibb.co/7Xs3qH7) (https://i.ibb.co/QppXRN2/Convert-ATF-pump-coupler-drawing.jpg) (https://ibb.co/QppXRN2)
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Thanks for posting the Guzziology page & pump web link, both great info. I read Dave's analyses years ago but forgot the part about the heat-treated couplers being oversized.....which is a great segue into my next observation: My coupler was INSANELY tight to the pump bore, almost had to resort to vice-grips to be able to turn it and pull it out at the same time; also pitted and slightly scored:
(https://i.ibb.co/xGLkWvB/20231204-105732.jpg) (https://ibb.co/xGLkWvB)
I can't imagine why the fit is so tight, and wonder about the pitting, also. I would have expected the fit to be similar to that of a wrist-pin in a con rod. If anyone can recall how their pumps felt on the bench, or have a pump handy to check the fit, that would be a good check to see if mine is truly too tight.
A custom-machined coupler would be great, but one with improvements would be the only thing to make it attractive enough to justify a small run. Like deeper engagement? Or a larger 1/4" std hex size to reduce the loading at the hex tips?
I discussed a larger hex with Rodekyl previously, but it was in the context of a larger hex also EDM'd into the cam shaft, so that a straight 1/4" shaft could be used. But failures at the cam-end are never mentioned, so maybe a custom shaft ground to 6 mm at the cam end and 1/4" at the pump end might work, and an existing coupler could be modified rather than machining a custom coupler.
So I'm still looking for a replacement coupler, and also looking around for an EDM resource to look at modifying my existing coupler, but the pits, scoring, and tight fit are still an un-resolved problem.
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Thanks for posting the Guzziology page & pump web link, both great info. I read Dave's analyses years ago but forgot the part about the heat-treated couplers being oversized.....which is a great segue into my next observation: My coupler was INSANELY tight to the pump bore, almost had to resort to vice-grips to be able to turn it and pull it out at the same time; also pitted and slightly scored:
(https://i.ibb.co/xGLkWvB/20231204-105732.jpg) (https://ibb.co/xGLkWvB)
I can't imagine why the fit is so tight, and wonder about the pitting, also. I would have expected the fit to be similar to that of a wrist-pin in a con rod. If anyone can recall how their pumps felt on the bench, or have a pump handy to check the fit, that would be a good check to see if mine is truly too tight.
A custom-machined coupler would be great, but one with improvements would be the only thing to make it attractive enough to justify a small run. Like deeper engagement? Or a larger 1/4" std hex size to reduce the loading at the hex tips?
I discussed a larger hex with Rodekyl previously, but it was in the context of a larger hex also EDM'd into the cam shaft, so that a straight 1/4" shaft could be used. But failures at the cam-end are never mentioned, so maybe a custom shaft ground to 6 mm at the cam end and 1/4" at the pump end might work, and an existing coupler could be modified rather than machining a custom coupler.
So I'm still looking for a replacement coupler, and also looking around for an EDM resource to look at modifying my existing coupler, but the pits, scoring, and tight fit are still an un-resolved problem.
Edited my post above. The coupler spins freely in the pump body - like you wrote: "wrist pin in a con rod".
I feel 11 mm is plenty of engagement, and if the socket was the correct size (not oversized) and the part properly heat treated, then 6 mm would be fine.
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It will be very interesting to see what the machinist comes up with. :popcorn: Thanks for everything you do for the Guzzi community, Charlie! :bow:
Rick.
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Here's an idea you don't want to hear. How bout an electric pump. I thought RK had that sorted out for working. He had more room w/trike.
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Here's an idea you don't want to hear. How bout an electric pump. I thought RK had that sorted out for working. He had more room w/trike.
It's been done of course. I saw an an Eldovert built by Dale Petersen at the WNY Rally years ago that had a Holley electric fuel pump as the atf pump. When I was planning to build one myself, I bought a pump used to circulate transmission or differential fluid through a cooler on a race car. I don't recall right now what Rodekyll was using.
With a coupler machined to the correct dimensions and heat treated properly, the problem would cease to exist, in my opinion.
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That would be the fix. If you could machine & press fit that one piece would be nice.
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With a coupler machined to the correct dimensions and heat treated properly, the problem would cease to exist, in my opinion.
Aaaaaaand, a coupler-to-housing interface with no play but no excessive drag, either. I like the idea of a larger (1/4") shaft, but that drives a custom shaft. I'd be confident with a 6 mm heat-treated coupler that ran smooooth in it's housing.
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Back when I built the EVert both Rodekyll and I had the cams from the 1100cc engine EDM’d and it worked a charm! I remember we sent the cams to someplace in Florida who did the EDM work, it was pretty inexpensive too. I don’t remember the name of the place tho. I can look but. Doubt I’ll fine it.. that was 16 years ago.
One thing I have wondered about, did the design team make the hex part the weak link on purpose so the other components would not get abused? Would you rather replace the hex drive or the whole pump?
My Evert foreground and RK’s Pink and Purple JackalVert (ridden from Alaska) at the 2007 National rally, AKA the flood rally at Money Creek Mn.
(https://photos.smugmug.com/All/i-JcX5M7H/0/5ff075ef/L/DSCN2152-L.jpg) (https://fotoguzzi.smugmug.com/All/i-JcX5M7H/A)
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I doubt that the design team made that coupler a sacrificial part, on purpose,I think it just turned out that way. :azn: The pump, being fed a constant supply of clean oil, should last a long time, I would think. Now that I think back to when I took my pump apart to replace the seal,and O ring, it was very hard to turn, so much so, that I took it all apart again, to see if I had assembled something wrong. When the cover , or retainer was tightened down, it was hard to turn. I attributed it to the new seal, and re assembled everything, but now I wonder about that leading to coupler failure. FWIW, I have logged about 4K miles on the bike since rebuilding the pump.
Rick.
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Aaaaaaand, a coupler-to-housing interface with no play but no excessive drag, either. I like the idea of a larger (1/4") shaft, but that drives a custom shaft. I'd be confident with a 6 mm heat-treated coupler that ran smooooth in it's housing.
That would be covered under by "correct dimensions".
That would be the fix. If you could machine & press fit that one piece would be nice.
What as one piece - the hex piece and coupler? That's what Dave Richardson did, but I'm not sure it's the best idea as it doesn't allow for any misalignment.
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Edited my post above. The coupler spins freely in the pump body - like you wrote: "wrist pin in a con rod".
Charlie, I'll ask this out in the open for my and Rick's benefit: When you said "coupler spins freely in the body...", are you saying that is the current condition of your "good" pump that you're keeping, or that's the optimum condition of a pump?
For myself and Rick's bike, I am very concerned about the tight fit, and I won't put mine back together until/unless I achieve a wrist-pin type smooth fit. This is the 3rd or 4th failure on this engine with only 51k miles on it, and I don't think it's more than 10k since I fixed it last. I've never looked this closely at the coupler, I always attributed failures to the shaft (and in one legitimate case, a leaking pump seal), but the visual evidence is clear that the coupler has suffered, whether heat-treated or not, and the tight-fit has to have contributed (remember the score marks). Rick: Knowing you have a tight fit on your rig, I would seriously consider pulling back apart and addressing that condition, lest you suffer my fate somewhere in the future. Your Cal 2 Auto may have had a nice-running pump, and I don't know any other way to rationalize your trouble-free time with it.
Thanks for the continueing info, Charlie.
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What as one piece - the hex piece and coupler? That's what Dave Richardson did, but I'm not sure it's the best idea as it doesn't allow for any misalignment.
I meant machine out hex in pump side & press in a hardened one. Most likely not enough room size wise.
[/quote]
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Charlie, I'll ask this out in the open for my and Rick's benefit: When you said "coupler spins freely in the body...", are you saying that is the current condition of your "good" pump that you're keeping, or that's the optimum condition of a pump?
For myself and Rick's bike, I am very concerned about the tight fit, and I won't put mine back together until/unless I achieve a wrist-pin type smooth fit. This is the 3rd or 4th failure on this engine with only 51k miles on it, and I don't think it's more than 10k since I fixed it last. I've never looked this closely at the coupler, I always attributed failures to the shaft (and in one legitimate case, a leaking pump seal), but the visual evidence is clear that the coupler has suffered, whether heat-treated or not, and the tight-fit has to have contributed (remember the score marks). Rick: Knowing you have a tight fit on your rig, I would seriously consider pulling back apart and addressing that condition, lest you suffer my fate somewhere in the future. Your Cal 2 Auto may have had a nice-running pump, and I don't know any other way to rationalize your trouble-free time with it.
Thanks for the continueing info, Charlie.
Both - current condition of my spare pump and the optimum condition. That's probably why I only have one with the deep socket coupler - I've replaced at least two tight ones with better/free turning ones. If I can't turn it easily with a 6 mm T-handle allen wrench, then it goes into the bin and I find better one.
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I plan to open up the front cover again this winter, to check the pump for tightness, to see if things have loosened up, or it remains tight to spin. I should to replace the cam chain tensioner anyway, and it will be a good time to address the hex drive issue. I think I will wait a while, to see what Charlies machinist comes up with. It would be awesome to replace the couple with something better. As far as the tightness, is there a chance the fit between the two parts can be sanded , or polished to make it spin with less resistance? I am pretty confident this tightness is at least partially responsible for failures.
Rick
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Keeping my eye on this thread. I've had my Convert going on 4 years now.
Because everything works and works well
(Good oil temps, clean fluid, no slipping, leaks or
Issues) I've left it alone, but I'm sure it will need
Something eventually.
Granted I've only put less than 1000 miles this last
year due to my travel schedule, but retirement is
coming and I plan to put more miles on the magic
Carpet
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I plan to open up the front cover again this winter, to check the pump for tightness, to see if things have loosened up, or it remains tight to spin. I should to replace the cam chain tensioner anyway, and it will be a good time to address the hex drive issue. I think I will wait a while, to see what Charlies machinist comes up with. It would be awesome to replace the couple with something better. As far as the tightness, is there a chance the fit between the two parts can be sanded , or polished to make it spin with less resistance? I am pretty confident this tightness is at least partially responsible for failures.
Rick
Definitely. I've chucked the coupler up in the lathe and polished the o.d. with fine emory cloth until the fit was more to my liking.
Brider: Did you get my message with links to timing covers and pumps?
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I should have done what you did, Charlie, with the emery cloth, on the pump coupler to get it to turn easier, while I was in there to reseal the pump. Live and learn! :laugh:
Message with links to timing covers and pumps? was that for me, or for Brider?
Thank you
Rick
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I should have done what you did, Charlie, with the emery cloth, on the pump coupler to get it to turn easier, while I was in there to reseal the pump. Live and learn! :laugh:
Message with links to timing covers and pumps? was that for me, or for Brider?
Thank you
Rick
Oops, sorry, links were for brider.
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Definitely. I've chucked the coupler up in the lathe and polished the o.d. with fine emory cloth until the fit was more to my liking.
Brider: Did you get my message with links to timing covers and pumps?
Yes I got the links, thanks. Another member replied to my Swap ad and has a pump with a coupler that looks great, exchanging data with him now. If I go that route, I think dressing the coupler surface for a smooth fit and having a hex shaft surface-ground to a better fit would be my least-invasive and most cost-effective fix.
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Hey, Brider, Im happy you found a coupler that will get you back on the road. Please keep us posted in how you polish it up, for smoothness,and how the reassembly goes when you get it. I am also keeping my fingers crossed, that Charlie's Machinist friend can come up with some improved solution for us. I will wait to hear from Charlie, before tearing mine down for inspection, etc. The next couple of winter months lend themselves to these types of projects, even in Arizona! :wink:
Rick.
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Just to open up some more options, this is the pump shaft from my 1976 Convert.
(https://i.ibb.co/zhK3hFf/20180626-232831-Small.jpg) (https://ibb.co/zhK3hFf)
noble emojis (https://emoticoncentral.com/category/noble)
As you can see it has a tang rather than a hex drive, the end of the camshaft has a corresponding slot.
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haven't been in my '76 yet... but i hope it has the tang drive !
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Just to open up some more options, this is the pump shaft from my 1976 Convert.
(https://i.ibb.co/zhK3hFf/20180626-232831-Small.jpg) (https://ibb.co/zhK3hFf)
As you can see it has a tang rather than a hex drive, the end of the camshaft has a corresponding slot.
I've seen that modification before, always wondered how well it would work (durability).
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Just to open up some more options, this is the pump shaft from my 1976 Convert.
(https://i.ibb.co/zhK3hFf/20180626-232831-Small.jpg) (https://ibb.co/zhK3hFf)
noble emojis (https://emoticoncentral.com/category/noble)
As you can see it has a tang rather than a hex drive, the end of the camshaft has a corresponding slot.
??? Camshaft has a slot? Hard to see from the photo, is the other end a hex? Looks too short, and the shoulder limits engagement. The shaft needs SOME axial clearance, so both ends of that shaft are limited by the cylindrical shoulder and engagement is going to be either net or less than the length of the drive feature (tang or hex).
Do you think that was a factory setup? Is yours a very early Convert?
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?
Is yours a very early Convert?
my thought too. I’ve seen one like that on a part out bike.
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Didnt only the 1975 or very early converts have that flat drive? The Hex drive piece, I believe was Guzzis new and improved version. I would not think the flat drive piece would be less failure prone.
Rick.
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Mine was built in mid '75 so is fairly early, "normal" hex-piece driven pump. I don't think any Convert had the flat drive from the factory.
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Mine was built in mid '75 so is fairly early, "normal" hex-piece driven pump. I don't think any Convert had the flat drive from the factory.
I was wrongly under the impression that the pumps with the circlip, and round pump retainer( early version) had the "flat drive", and the ones with the triangular retainer ( later version) have the hex piece. In looking at Briders photo, I can see the circlip version actually has a hex drive coupler. I guess thats just the "shallow" one.
thanks
Rick.
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Here is the simplest fix . You want to have made a replacement pump drive pin hardend ground polished burnt hex concentric. Ok deside deep spline ect my thinking is that the last desinge thefactory came up with would be the one. Now iwould go with the clearance of the cam match that. Now the only part needing replacement would be the hex shaft.put it back together ride it,it should go twice as far as last. How ever i would take a look at it at a bout 70% of how far it went before. To avoid sitting on side af road. That part is about as simple as could be. I would advise 20 or so the cost is in thr set up draw up prints and fax to some tool shops with photos ect now you have parts to offset your cost for others
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??? Camshaft has a slot? Hard to see from the photo, is the other end a hex? Looks too short, and the shoulder limits engagement. The shaft needs SOME axial clearance, so both ends of that shaft are limited by the cylindrical shoulder and engagement is going to be either net or less than the length of the drive feature (tang or hex).
Do you think that was a factory setup? Is yours a very early Convert?
The tang on the end shown engages with a slot in the end of the camshaft. The end you can not see has the normal hole for the pin that drives the pump lobes.
This bike is in Australia but got here via America, Holland and England so not sure of original manufacturer date, but it is early 1976 from what I can tell.
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The tang on the end shown engages with a slot in the end of the camshaft. The end you can not see has the normal hole for the pin that drives the pump lobes.
This bike is in Australia but got here via America, Holland and England so not sure of original manufacturer date, but it is early 1976 from what I can tell.
Thats interesting. Your version does not use a hex shaft at all. It uses a flat slotted interface at the cam, and the pin that drives the pump, at the other end
Rick
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A member here offered up a front cover with a coupler that looks very un-worn and spins freely in it's pump, so I'm going to go with his OEM cover/pump and try to size a custom shaft to take up any excess slack. I think I have a source to hardness-test both my worn coupler and his to establish baselines. For a test run, I also found a correct-size wooden dowel and used 180 then 220-grit paper and some WD-40 and hand-sanded the bore of my pump housing (which was binding so badly I could hardly turn it by hand) and voila! I got my pitted, scored coupler to turn in it like it should, nice and smooth.
So my plan of attack is to utilize a correct-hardness coupler with a good hex, dress the bore it rides in as necessary to get a smooth, minimal-drag fit, and have a shaft ground to minimize slop. Most of the risk minimized with minimal cost.
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So my plan of attack is to utilize a correct-hardness coupler with a good hex, dress the bore it rides in as necessary to get a smooth, minimal-drag fit, and have a shaft ground to minimize slop. Most of the risk minimized with minimal cost.
That's what I did 30k miles ago, so far so good. :wink:
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(https://i.ibb.co/n35pbWZ/20180626-232605-Small.jpg) (https://ibb.co/n35pbWZ)
(https://i.ibb.co/19Jv9DD/20180626-232831-Small.jpg) (https://ibb.co/19Jv9DD)
(https://i.ibb.co/xg078Rz/20180626-233333-Small.jpg) (https://ibb.co/xg078Rz)
On the attached pictures a view of the modified camshaft and coupler as build in in my 1975 Convert and California 1100i Convert
The slotted end in the camshaft is 4,5 mm wide and 12 mm deep
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No hex in your case. Just the flat drive. How does that work out? Did you make it deeper?
Rick
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(https://i.ibb.co/19Jv9DD/20180626-232831-Small.jpg) (https://ibb.co/19Jv9DD)
On the attached pictures a view of the modified camshaft and coupler as build in in my 1975 Convert and California 1100i Convert
The slotted end in the camshaft is 4,5 mm wide and 12 mm deep
??? Your center photo is the same one DanPW posted for his '76 'vert. Are you and he the same guy? Is this from the same bike? Did this idea exist on the '76 and you reproduced it on the 1100i?
Guess it doesn't matter, really, except to ask if this is a production configuration from '75-'76, or did you or someone else do this mod? Looks like a FAR smarter solution to provide reliable torque to the pump AND allow for mis-alignment. Some might say there's only (2) points of contact between the cam & drive "tang" as opposed to (6) for the more common hex, but I can't see your configuration stripping no way no how.
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There is no hex coupler to drive the pump just the flat. It works out very well. I did over 100k miles with this bike, no problems.
The slotted end in the camshaft was made with a grinding machine. I did not make the hex bore deeper, no need for that modification.
I am not the same guy as DanPW and it is not from the same bike. This modification was made i the mid 70ties by a Dutch Guzzi dealer
to prevend future problems with worn hex drives. There are a few bikes with this modification in the area where I live.
I reproduced this on my 1100i and is functioning now for 17k miles
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This modification was made i the mid 70ties by a Dutch Guzzi dealer
to prevend future problems with worn hex drives. There are a few bikes with this modification in the area where I live.
Wow. Kind of surprising (and a shame) that this fix did not become a widespread "known" fix....or maybe it did?.....and we spend so much time focusing on the hex coupler. Would require a good machinist and pulling the cam, but do it once and DONE.
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The modified drive does look the same as mine.
My bike was in the Nederlands from November 1998 to December 2007, so I expect the modification was done there. If you have access to a lathe and a mill it would be an easy modification.
Mine has held up well with no signs of wear or damage to the seals.
Could the work have been carried out by TLM?
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Its too bad that this fix requires cam removal. It looks like a good way to put an end to this problem. Hopefully Charlies machinist will come up with a different fix that works.
Rick.
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If I were doing this repair, I don't think I would want the trouble and expense of pulling and modifying a cam. Should things go astray either in making the slot or afterwards, you've probably lost that cam. I would go with a square drive. Creating a square hole in the standard type coupler would be easier than a hex. The coupling connection to the cam hasn't been mentioned as a problem, has it? Creating a "fitting" square drive would also be easier than a hex.
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Hey, Thats thinking outside the box.....Or would that be considered "inside the box", since its a square ! :wink:
Rick
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I would get a sporting cam , have it modified and install it at my leisure.
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If I were doing this repair, I don't think I would want the trouble and expense of pulling and modifying a cam.
This is my current mindset. But finding a hotter cam and modifying in my (non-existent) leisure time sounds like a great idea.
So, a drive piece with a square coupler end.....square on one end and hex on the other? Would that have to be a machined part (and heat-treated?), or could a stock hex (1/4") be surface-ground?
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:popcorn:
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UPDATE: I received the replacement cover with "good" pump (good hex shape, spins freely & smoothly) from a member here. Couple of questions though:
In the photo, you can see I pulled the pump housing out of the front case and separated the coupler from the housing and re-inserted it into the pump-well and star-shaped thingy that rotates in there. The empty pump housing is sitting to the right in the photo.
In the bottom/center is my old, worn coupler turned upside-down with the female hex pointing down for reference.
Q: I didn't pay attention to its position when I pulled it out, so what do those punch marks on the larger star-shaped thingy and the one pinned to the coupler shaft have to do with anything? Are they used for some kind of alignment?
Q: On my worn coupler, the punch mark is on the side opposite from the shaft as opposed to the coupler on the replacement. Which configuration is the proper placement?
Note the flattened surface on the larger sealing o-ring. This seal contributed to a slipping condition on one of my TC-slipping bouts. Replaced the o-ring and the slipping went away. Fresh o-ring & seal will go in with the new pump.
(https://i.ibb.co/9nr46xh/New-pump-edited.jpg) (https://ibb.co/9nr46xh)
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The shaft is offset in the housing. Align the dots with the threaded hole between the cast oil tubes.
This will allow the housing to slide on. The other inner rotor was upside down. Is that a picture of the new pump?
That O ring is normal for a used one. It sits flat against the housing but the case side is coned so it set in that shape.
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Align the dots with the threaded hole between the cast oil tubes.
This will allow the housing to slide on. e.
Huh? The "female" star-thingy with the punch mark is 5-point, but the "male" star-thingy with the punch mark is 4-point, and there is no physical way to align the punches in any orientation that I can see. So what are they for again? I might want to look at the factory manual before I comment further.
Putting the pump together and back in the front cover is no problem, as the coupler can be turned with a 6mm hex wrench as you're inserting the pump. Clocking the coupler with the hex shaft inserted as you mount to the engine is a different challenge, but not rocket science.
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Huh? The "female" star-thingy with the punch mark is 5-point, but the "male" star-thingy with the punch mark is 4-point, and there is no physical way to align the punches in any orientation that I can see. So what are they for again? I might want to look at the factory manual before I comment further.
Putting the pump together and back in the front cover is no problem, as the coupler can be turned with a 6mm hex wrench as you're inserting the pump. Clocking the coupler with the hex shaft inserted as you mount to the engine is a different challenge, but not rocket science.
When aligned the peak of the 4 point inner rotor, opposite the punch mark, will drop into the valley of the outer rotor. This will allow the inner rotor peak with dot to align with the dot on the peak on the outer rotor. It will cause drive shaft. to be offset and allow the housing to drop on.
The dots are just for alignment, once the pump rotates it doesn’t matter where they are.
If you can get the housing on and the pump assembled by fiddling with the shaft you are done. The marks are just to aid in assembly, no more no less.
(https://i.ibb.co/prDN51j/8-A79-D9-AE-A54-F-4875-BFA7-82-ADB5-E165-D5.jpg) (https://ibb.co/prDN51j)
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When aligned the peak of the 4 point inner rotor, opposite the punch mark, will drop into the valley of the outer rotor. This will allow the inner rotor peak with dot to align with the dot on the peak on the outer rotor. It will cause drive shaft. to be offset and allow the housing to drop on.
Used your technical engineering drawing and re-fit the coupler and sure enough, I see the concept now. Thanks for clarifying it.
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I'm a new member. I recently purchased a 1977 convert. If Charlies machinist comes up with a fix for purchase I would be interested in being in on it.
Dan
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I'm a new member. I recently purchased a 1977 convert. If Charlies machinist comes up with a fix for purchase I would be interested in being in on it.
Dan
Excellent, Dan. I sure would be for sure, and I am sure that a few other "Convert Perverts" would be interested! :grin: We will have to wait and see, if he is able to do it.
Rick D.
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Excellent, Dan. I sure would be for sure, and I am sure that a few other "Convert Perverts" would be interested! :grin: We will have to wait and see, if he is able to do it.
Rick D.
I've contacted two machinists so far, waiting to hear back from both.
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I've contacted two machinists so far, waiting to hear back from both.
Thank you very much for that , Charlie. Much appreciated.
Rick D.
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Re: Surface grinding
I'm ready to have a 1/4" std hex tool (measures ~6.223 mm) ground down to the 6.15 mm dimension I need (measured the replacement female coupler I got my hands on), but I'm wondering what instructions to give the shop; grind equal on all 6 sides, or grind 3 adjacent sides to achieve the desired 6.15 mm across the flats? Theoretically it seems that just grinding 3 flats gets to where I need, but is there a concern about heat-treat depth being ground away on only 3 sides?
The amount to be ground off turns out to be ~.003", so to grind all (6) sides means .0015" off each side, seems too small to control.
I plan on giving the shop a 3" section of tool, then I'll cut it to length myself.
Am I over-thinking this?
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6, if doing 3 flats won’t be the same width. Measured across , flats will be correct but flat width will vary.
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:popcorn:
Rick.
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Highly technical drawing. This is cutting four sides, 3 can’t happen.
Distance across would be equal, flat width would vary.
Being that the drive is an Achilles Heal, you want it as best as possible.
Your talking removing very little to get to your spec., I get it, but this should answer your question. How important is it to you, I can’t answer that.
(https://i.ibb.co/CKPtWZ1/584-BA6-BF-6990-4-A34-888-C-4-D9-B0-E3-B4-D95.jpg) (https://ibb.co/CKPtWZ1)
That’s incorrect, can be done with 4 and 6 cuts, can’t be done with 1,2,3,5. It will look like a isohexatrapizoid.
Drawing is off, need to update software in my pen.
I’m going to go fit a square peg in a round hole.
Ok final answer, 1, 2, 3 cuts = no go. 4, 5, 6 to get all measurements equal (measured across flat to flat and flat width) (order the OEM hex key, can you? and be done). I would still look into the slotted cut drive, pretty common for pump drives so it’s proven reliable).
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Like a 6 point socket or box end wrench compared to a 12 point. In the airplane shop 12 point tools were not used. I don't think they were even allowed.
kk
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Just throwing this out there but if the slotted drive is far superior why not go that route?
The time involved with removing the cam and having the slot cut is not that much. A couple more hours of work and you can permanently put this to bed, just a thought.
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Been following this thread but I seem to be missing something, but as I wrote in this thread at the beginning I done mine some time back on the mill with a rotary table and a stone and light passes as to not get the hex hot , the mill controls the cut depth and the rotary table keeps it central, I machined one end more than the other as the pump had more clearance than the cam ,when finished if all true the hex should be a nice equal fit when rotated to all 6 positions at each end I dunno Ill keep following may be I done something wrong but you have my attention . Ray
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Been following this thread but I seem to be missing something, but as I wrote in this thread at the beginning I done mine some time back on the mill with a rotary table and a stone and light passes as to not get the hex hot , the mill controls the cut depth and the rotary table keeps it central, I machined one end more than the other as the pump had more clearance than the cam ,when finished if all true the hex should be a nice equal fit when rotated to all 6 positions at each end I dunno Ill keep following may be I done something wrong but you have my attention . Ray
Mine was 6.2 mm for the full length, and as I have written previously, it's been working fine for the last 32k miles and I have no reason to believe that it won't go at least that much more, plus.
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Have only travelled about 6000 mile with mine and intend to inspect it at around the 10000 mile mark , and hopefully all will be well. time will tell
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Highly technical drawing. This is cutting four sides, 3 can’t happen.
Distance across would be equal, flat width would vary.
Drawing is off, need to update software in my pen.
Of course! And thanks for you highly technical dwg, those are the best. I have easy access to engineering graphics software, so I'm just gonna lay it out myself to have good data to give the shop. Might post a sketch here.
You're right about the slotted cam-end, I love that idea but those few hrs work to remove the cam equate to MONTHS in my world, done 15 min at a time amongst the other more pressing projects I have, and if I can get 36k miles out of a custom-grind drive hex like Charlie, that should last me YEARS at the pace I put miles on this bike.
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Of course! And thanks for you highly technical dwg, those are the best. I have easy access to engineering graphics software, so I'm just gonna lay it out myself to have good data to give the shop. Might post a sketch here.
You're right about the slotted cam-end, I love that idea but those few hrs work to remove the cam equate to MONTHS in my world, done 15 min at a time amongst the other more pressing projects I have, and if I can get 36k miles out of a custom-grind drive hex like Charlie, that should last me YEARS at the pace I put miles on this bike.
I might be looking at the cam change through rose colored retirement glasses.
Maybe the OEM hex, might not be as tight as custom, but it will allow some movement to compensate for misalignment. I know you’ll do what’s best for you and the bike all things considered. Would love to see the sketch if you can post.
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I have the same problem to tackle in advance as part of my Convert rebuild. I've created a CAD model from the old, ruined socket that came with the bike and I've just sent it off to be milled from A2 steel. Once it's back, that will then go for hardening, assuming I didn't make a mistake in the design! Will let you all know how it goes. If all's well then I'll make the model files available.
This is sticking with the 6mm hex socket. I did a mock up with a 7mm socket and a custom 7-to-6mm hex bit, but I was concerned about making the camshaft end of things the weak link. From what I can tell, a properly hardened 6mm socket with a touch over 11mm engagement should be up to the task.
(https://i.ibb.co/s6KWdZc/convert-hex-socket.jpg) (https://ibb.co/s6KWdZc)
(https://i.ibb.co/7nxpTsQ/convert-hex-socket2.jpg) (https://ibb.co/7nxpTsQ)
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I have the same problem to tackle in advance as part of my Convert rebuild. I've created a CAD model from the old, ruined socket that came with the bike and I've just sent it off to be milled from A2 steel. Once it's back, that will then go for hardening, assuming I didn't make a mistake in the design! Will let you all know how it goes. If all's well then I'll make the model files available.
This is sticking with the 6mm hex socket. I did a mock up with a 7mm socket and a custom 7-to-6mm hex bit, but I was concerned about making the camshaft end of things the weak link. From what I can tell, a properly hardened 6mm socket with a touch over 11mm engagement should be up to the task.
(https://i.ibb.co/s6KWdZc/convert-hex-socket.jpg) (https://ibb.co/s6KWdZc)
(https://i.ibb.co/7nxpTsQ/convert-hex-socket2.jpg) (https://ibb.co/7nxpTsQ)
:thumb: :thumb:
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Model looks good, RecentConvert. I was able to scrounge up a very sharp-looking original part so I'm going to use that. I had it hardness-tested and it came back within Rc range. Right now my .250" nominal tool hex-drive part is at my machinist's shop waiting to be precision ground down to custom size, but I made the mistake of saying "no hurry, I have another bike to ride" so it's at the bottom of his stack. I call once a week to remind him.
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Cleaning the garage and found this today…
31.5 x 6…
(https://i.ibb.co/R0skc4t/IMG-1095.jpg) (https://ibb.co/R0skc4t)
(https://i.ibb.co/Tq4rdsJ/IMG-1096.jpg) (https://ibb.co/Tq4rdsJ)
Not needed here anymore…
$10 donation to the board and it’s yours
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Sent PM
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I'm nearing the end of this saga, I ordered the pump seals to put the "new" timing cover and pump back on, and got my special-grind hex back from the shop. The machinist is a friend of mine and he only charged me $25 to grind down a stock 1/4" hex wrench, but I told him to only take .0035 off each face, and he took .007 off instead :angry:. he said if it didn't work he'd give it another try to take less off of another part, but I tried a fit-check with his ground part and it felt pretty darn tight. I also got Chuck's NOS hex drive for comparison, and here are a set of parts with their dimensions (numbers on top are mm):
(https://i.ibb.co/WFLWBJb/Cal-2-Auto-pump-drive-shaft-sizes.jpg) (https://ibb.co/WFLWBJb)
As you can see, the in-service hex shaft is basically the same measurement as the stock 6mm wrench on the right, which makes sense because that's what I made it from the last time I went thru this fiasco. The NOS part measures the smallest of the bunch, and I wonder why, as in why did Guzzi feel an undersized 6mm was better than a nominal tool size?
So my ground part is still the largest size despite the excess amount the machinist took off. And it really feels good and snug in both the pump impeller at the top of the image, and in the end of the cam.
My reluctance in just cutting to length and using it is knowing whether or not the grinding went thru the depth of the heat-treated hard surface to softer material below? Can anyone who knows about heat-treating opine about this? I think i still have access to have both the tool on the right and the ground part hardness-tested, so that may tell me something, but I'd really like to install the ground-part with the nice, snug fit.
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I have been following this thread with great interest. I have to get inside the front cover of my 76,and smooth out the surfaces so the pump turns easier,without so much "drag". I am also still looking for one of the later style adapter,and a good Hex, if anyone has one they would like to sell. I hope it all goes back together well for you. :thumb:
Rick.
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Update: I had the part I had surface-ground and the 6mm stock took Rc hardness tested today, both tested in the same range of Rc 50+, which tells me that the surface-grinding did NOT go beyond the case on the part, so since it fits slightly better than the 6mm wrench (which fits better than the NOS factory part), I'm going to cut it to length and button that girl back up!
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Update: I had the part I had surface-ground and the 6mm stock took Rc hardness tested today, both tested in the same range of Rc 50+, which tells me that the surface-grinding did NOT go beyond the case on the part, so since it fits slightly better than the 6mm wrench (which fits better than the NOS factory part), I'm going to cut it to length and button that girl back up!
I think good quality "allen" wrenches are made of chrome vanadium tool steel. They are then through hardened (oil quenched) then tempered to reduce brittleness. Properly processed they are the same Rockwell hardness throughout. No worry about grinding through a case hardening.
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Properly processed they are the same Rockwell hardness throughout. No worry about grinding through a case hardening.
That explains it then, thanks!