Wildguzzi.com
General Category => General Discussion => Topic started by: jacksonracingcomau on August 31, 2018, 04:17:37 PM
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Mine will go together soon
Any sage advise wecome.
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The ones I fixed were from over revving. Valve heads would then come off stem. Some had cam problems. It's all been documented here if you search around. Some interesting reads for sure.
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Martin, I suggest you send a pm to Iceblue. Brian has a lot of experience with the 4 valve engine and has done a lot of research on it.
From what I remember, the problems came from the two piece valve stretching causing the head to fall off. Cause(s) amongst other things were the valve springs were too strong and something about the cam needing to be 14mm instead of 12. I think he got valves made but I have heard that there is a Nissan valve that works, and also a Suzuki 250 valve. People have just used the outer only on the spring.
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IN my experience, which was a long time ago and not encyclopaedic, the two major causes were the overly heavy valve springs, (They just doubled up on the same springs as they used with the 2 valves but the stems were much weedier. Wasn't aware until recently of the two part nature of the valves.) this may alsoof been a contributor to the cam and tappet problems. The other one was heat dissipation. The finning on all the early smallblocks was always marginal and if the heads were allowed to get dirty so their ability to dissipate heat was impaired they would always tend to shed valve heads or in the case of Monzas and V65's crack heads between the seats and the plug 'ole. The Larios were even more grossly under finned so heat dispersion became even more of an issue. As for the 750 versions, (Shudder!) they were truly the acme of awful.
If you haven't already I suggest you call Mario at Thunderbikes. He used to race one I believe and was I think the author of the Suzuki GN 250 valve and spring fix.
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Or you can do what Chuck In Indiana did and adapt a genuine MG 750 4V aero drone motor.
(https://thumb.ibb.co/eFF0cz/DSC05137.jpg) (https://ibb.co/eFF0cz)
GliderJohn
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Thanks all
Have read and heard loads but no definitive answer, all I have heard except very few now keep revs below 8. This would be one answer.
The few have given them grief, one a 750 cc factory dakar bike, raced in the proper heat, still going strong and fast.
Another a road race bike set up with special cam very modified heads. Very fast. But long gone, possible I find it one day but not likely soon
I have the later std cam just back from being lightly cleaned up by Phil Joy in UK, gave followers a tickle up too. May dlc them in aus, mob in geelong does that.
KTM elephant feet adjusters on shopping list
Yet to decide on valves and springs, but my one had lighter suzuki ones, definitely too light for job.
I only want factory performsnce for now, detuning it not really the answer or question.
May be as simple as inadequate valves but fact that 750 road bikes still did it after years of factory mods makes that unlikely. They never sold fixed afaik
But rfactory race bikes didn't drop valves, they broke other bits but not valves. In desert heat, pulling through sand.
May have to look inside the dakar bike
Next question
Why did the flat tappet recent 8v wear out cams and has anyone fixed that without resorting to rollers ?
I realise thay don't drop valves but the cam wear is the common ground
Rare as RHS s on 2v bb and high cam belt 4v afaik
Sb 4v definitely had camshaft issues, intriguing part is new v85 has gone to roller tappets like the bb 8v.
There is an answer here somewhere
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The 8V's don't wear out cams.
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Third world parts for the internals did not help the Larios. There’s lots of speculations and fixing symptoms seems to be what most do. Someone went with Nissan valves (Brian??) and I went with Kibblewhite valves/springs, et al. I DLC my Cam also for good measure. If heat is a problem I’m running a venerable sweat-box with mine. Pulling 15+% more hp with major head work, bigger valves, racing cam, much more fuel. Nobody dropping valves with solid parts, but nobody using solid parts either. Use a band aide and take your chances. The stock valves are shite. My 2 pennies.
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How much spring pressure is too much, measured on or off the seat?
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How much spring pressure is too much, measured on or off the seat?
Depends on your valves. For high revs and solid valves stock is about right according to Milich and a German dude Martin. I wouldn’t do it on stick valves. What does that tell ya’?
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I don’t disagree with what anyone has said about the Lario flaws. My mentality is simply why live in a glass house. Prove to me with proper metallurgy and engineered parts that there are valves dropping. We simply don’t have that data
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Depends on your valves. For high revs and solid valves stock is about right according to Milich and a German dude Martin. I wouldn�t do it on stick valves. What does that tell ya�?
I'm looking for actual installed PSI to make a comparison to other known examples...
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i've had two lario engines drop valves, current setup is stock valves with soft springs , and a 8500 rpm rev limiter
it seems to keep together for now.
basically the 4 valve engines were not properly engineered, using valve springs from the 2 valve engine ( why?) the cam and followers wear out pretty fast.
when the cam is damaged the quitening ramps wear out, and the valves are violently opened. wich doesnt help the already fragile valve train.
the V35 imola2 suffers even more from dropped valves , because it revs higher .
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I'm currently building a lario also and have been told by a friend that races them that the quality of the original valves and the soft cam and followers are the culprit. Replace the valves with kibblewhite stainless valves and dlc coat the cam and followers and it should never have a problem. Changing the valve springs to a softer spring drops redline and can cause valve float at the upper rpm range.
Sent from my moto x4 using Tapatalk
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I'm currently building a lario also and have been told by a friend that races them that the quality of the original valves and the soft cam and followers are the culprit. Replace the valves with kibblewhite stainless valves and dlc coat the cam and followers and it should never have a problem. Changing the valve springs to a softer spring drops redline and can cause valve float at the upper rpm range.
Sent from my moto x4 using Tapatalk
Amen brother
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Kevdog and Ossaman - been awhile ago but when looking at the Kibblewhite site there was no cross reference to valves for the Lario and email contact was likewise not helpful.
Got Kibblewhite part numbers?
or were your valves bespoke?
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Kevdog and Ossaman - been awhile ago but when looking at the Kibblewhite site there was no cross reference to valves for the Lario and email contact was likewise not helpful.
Got Kibblewhite part numbers?
or were your valves bespoke?
Mine are not stock. I had heads milled and using larger valves than stock. Maybe Ossaman can help here.
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I actually haven't assembled my heads yet but I bought new lario valves from Stein dinse before I gathered all the info I have now. I believe that you need to measure your valves and order blanks from kibblewhite and have them cut to length and the keeper groove cut in. I wish I would have gone this route but I'm going to try the Stein dinse valves for now and keep a very close eye on them.
Sent from my moto x4 using Tapatalk
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not sure you need the stiff original valve springs , the valves are lighter, the rockers heavier but there are two sets of springs operating one rocker.
the original lario valves were made from some steel , and were magnetic current guzzi valves are stainless, only the hardened tip at the top is magnetic
i started collecting parts to build a spare engine ,
latest find is a set of 86 mm pistons and cylinders for a lario,
never seen those before
some pistons from left to right : 86 bigbore for lario, stock lario, imola 2 bigbore, v35 imola2
(https://gdurl.com/zjT4)
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The 8V's don't wear out cams.
Actually Lario problem is similar to BB 8v one, it is the flat tappets that wear. cam follows,
Factory sells / gives cams in kit for a reason
Any 8v BB 's been ridden for long after tapets worn ? Look at cam
But agree with all above, good valves and cam/followers dlc'd should fix issue
Spring pressure will be measured and springs bought
But I do want mine to see 9 without collision
KTM elephants foot adjusters may be blind alley but looking good to me right now, anything that makes valve train easier has to halp.
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Actually Lario problem is similar to BB 8v one, it is the flat tappets that wear. cam follows,
Factory sells / gives cams in kit for a reason
Any 8v BB 's been ridden for long after tapets worn ? Look at cam
No, the problem is completely dissimilar. Using that logic is like pulling the head off a Lario that has dropped a valve and seeing a smashed up piston and saying "Gee Whizz! Larios have a problem with their pistons!"
The reason cams are part of the kit are twofold. Yes there is usually some compromise to the cam but the real reason is that flat and roller tappet profiles are completely different.
The thing that kills 8V big block tappets is I believe related to the beehive springs. Despite being chosen specifically to combat surge at certain speeds some form of occilatory effect occurs which allows the tappet to leave the opening flank of the cam.
If you look at the nose circle of the cams they will show a noticeable 'Bullseye' pattern, it's almost like a tempering mark which is unsurprising because that is exactly what it is.
The nose circle is NOT the point of highest load on the cam, in fact the loadings that point are quite low. The point of highest load is at the base of the opening flank where the cam in not only being asked to overcome spring pressure but also accelerate the mass of the valvetrain.
At a certain point though the engine speed will coincide with the surge issue in the spring, the tappet will leave the cam and then slam down on the nose circle. Because the DLC coating is only microns thick and is also very frangible it will crack and craze, (This can be seen with the naked eye as a changing of hue of the coating but can be very clearly seen with images made with an electron microscope.).
When at rest and assisted by the the fact that the 8V runs very cool a lot of moisture will tend to accumulate in the rocker covers and then drips down into the cam weirs and onto the tappets. This will penetrate the cracks in the DLC and attack the parent metal of the tappet. After some indeterminate number of cycles when the engine is started again the sweeping action of the cam across the tappet will begin to abrade the lifting coating and the tappet fails. This is why failures seem on the whole to occur earlier in cooler, damper, climates.
The 'Bullseye' effect on the nose circles is due to the hammering caused by the descending tappet, it's a simple witness mark but by the time the cams are seriously compromised by the damaged tappet it is easy to see that the abrasion begins on the opening flank, not the nose, of the lobe.
In my experience, which as I've said is not nearly as extensive with the smallblock 8V the wear patterns on both cam and tappet are far more traditionally indicative of too heavy springs exerting too great a load on cam and tappet faces. The heavy seating load imparted by the springs must also be murder on the necks of the very thin stemmed 4V valves. It's a recipe for wiped cams and torn off valve heads and, surprise, surprise! That's just what happens.
Pete
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No, the problem is completely dissimilar. Using that logic is like pulling the head off a Lario that has dropped a valve and seeing a smashed up piston and saying "Gee Whizz! Larios have a problem with their pistons!"
The reason cams are part of the kit are twofold. Yes there is usually some compromise to the cam but the real reason is that flat and roller tappet profiles are completely different.
The thing that kills 8V big block tappets is I believe related to the beehive springs. Despite being chosen specifically to combat surge at certain speeds some form of occilatory effect occurs which allows the tappet to leave the opening flank of the cam.
If you look at the nose circle of the cams they will show a noticeable 'Bullseye' pattern, it's almost like a tempering mark which is unsurprising because that is exactly what it is.
The nose circle is NOT the point of highest load on the cam, in fact the loadings that point are quite low. The point of highest load is at the base of the opening flank where the cam in not only being asked to overcome spring pressure but also accelerate the mass of the valvetrain.
At a certain point though the engine speed will coincide with the surge issue in the spring, the tappet will leave the cam and then slam down on the nose circle. Because the DLC coating is only microns thick and is also very frangible it will crack and craze, (This can be seen with the naked eye as a changing of hue of the coating but can be very clearly seen with images made with an electron microscope.).
When at rest and assisted by the the fact that the 8V runs very cool a lot of moisture will tend to accumulate in the rocker covers and then drips down into the cam weirs and onto the tappets. This will penetrate the cracks in the DLC and attack the parent metal of the tappet. After some indeterminate number of cycles when the engine is started again the sweeping action of the cam across the tappet will begin to abrade the lifting coating and the tappet fails. This is why failures seem on the whole to occur earlier in cooler, damper, climates.
The 'Bullseye' effect on the nose circles is due to the hammering caused by the descending tappet, it's a simple witness mark but by the time the cams are seriously compromised by the damaged tappet it is easy to see that the abrasion begins on the opening flank, not the nose, of the lobe.
In my experience, which as I've said is not nearly as extensive with the smallblock 8V the wear patterns on both cam and tappet are far more traditionally indicative of too heavy springs exerting too great a load on cam and tappet faces. The heavy seating load imparted by the springs must also be murder on the necks of the very thin stemmed 4V valves. It's a recipe for wiped cams and torn off valve heads and, surprise, surprise! That's just what happens.
Pete
Yeah springs are the common culprit in most opinions
In both cases changing the spring would have been easy fix if it was case.
But my lario engine, fixed by guru with suzuki springs both dropped a valve and destroyed follwers.
Cam worn beyond use
Of course it worked for lady owner before me, only using some revs did it fail, actually less than 7500 when it popped, but cam wear had obviously already happened.
Correct seat pressure loaded and not are obviously important, but underlying issue is greater than that.
not sure you need the stiff original valve springs , the valves are lighter, the rockers heavier but there are two sets of springs operating one rocker.
the original lario valves were made from some steel , and were magnetic current guzzi valves are stainless, only the hardened tip at the top is magnetic
Thanks, that makes sense, they obviously have tried, posthumously it seems
I don’t disagree with what anyone has said about the Lario flaws. My mentality is simply why live in a glass house. Prove to me with proper metallurgy and engineered parts that there are valves dropping. We simply don’t have that data
Yours one of few that have been built to rev
What sustained revs are you happy pulling ?
How many miles so far ?
ATM I'm still trying to find out fatory fix for dakar bikes, have a lead on factory engineer at time, will post here if I get answer, might be a while.
Now I'm getting obsessed, it is a disease
If I can get std one to hold together, next one will make some grunt, potential is there for sure but I need to make sure the pin has been deactivated before I throw too much explosive in the grenade.
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Actually Lario problem is similar to BB 8v one, it is the flat tappets that wear. cam follows,
Factory sells / gives cams in kit for a reason
Any 8v BB 's been ridden for long after tapets worn ? Look at cam
But agree with all above, good valves and cam/followers dlc'd should fix issue
Spring pressure will be measured and springs bought
But I do want mine to see 9 without collision
all the lario/ v75 dyno results i have seen have the max power at around 7000 RPM, and it hangs on to power up to 8000.
after 8000 power drops off sharply
no use revving it higher, it will be making less power.
if you want more revs, you will need at least a hot camshaft and bigger carbs.
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all the lario/ v75 dyno results i have seen have the max power at around 7000 RPM, and it hangs on to power up to 8000.
after 8000 power drops off sharply
no use revving it higher, it will be making less power.
if you want more revs, you will need at least a hot camshaft and bigger carbs.
Thanks again, bigger carbs def on next but this one won't do much more than std. Vaglia tach only a rough guide, Don't need a dyno but a decent tacho will at least give me a referece point.
Factory claimed peak at 7800, others have claimed 8500. A little overev before it goes pop would be nice, also preps it for building faster one next.
Mate who raced very modified one in 90's had safe 10, but race bikes don't do big miles so longevity of camshaft & followers was prob never really tested. As you said before, that is definately a major part of the problem. Intend to prove fixed before anything else.
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from a well developed v75 from a club member, some head work, pod filters and open exhaust
(https://gdurl.com/WpqG)
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from a well developed v75 from a club member, some head work, pod filters and open exhaust
(https://gdurl.com/WpqG)
How long has that held together ? Miles ?
Mine will be a 650 for now, might go a few more rpm. But if it does similar safe for 10000 miles I'd be happy. On the noise, of course.
Take it that has ligher valve springs than stock ? Same late sb 2 valve springs Iseblue uses ?
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Ok I am back in oz with chuck's lario, my one that dropped valve and one 750 4 valve head with rockers.
Mine and chucks have cam worn to nothing, every valve stem, pushrod, rocker adjuster hammered.
Guess his was seconds from going pop
Both these two had light valve springs
Intriguiong one is 750 head, this would have had later cam, but valves and rocker adjusters are chewed out just like the other two. But valve springs I think are original, certainly much heavier than the other two.
Dummied a motor up with carb springs for valve springs just to measure clearance, with nearly new OE 14mm cam, have loads of valve-valve but inlet valve to piston is 0.050"
WITH CHUCK's aero cam that becomes 0.030" def not enough.
So tell me Lario people, anyone with late 14mm cam, do rocker adjusters and valves still take a hammering ?
Easy enough to fit lash caps and hard adjusters but symptom and cause getting to me here.
Very tempting to assemble with piston fly cut for clearance but still feel there is another underlying problem.
Am all ears
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all the four valve engines i stripped had worn camshafts.
in my opinion cams and followers on a lario are marginal at best.
the valve train just wasnt designed to open two valves with one cam.
i want to try having the camshaft DLC coated.
smallblock adjusters wear out pretty fast , some people use yamaha adjusters.
the rest of the valve train should be OK , if you use good valves and spings
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all the four valve engines i stripped had worn camshafts.
in my opinion cams and followers on a lario are marginal at best.
the valve train just wasnt designed to open two valves with one cam.
i want to try having the camshaft DLC coated.
smallblock adjusters wear out pretty fast , some people use yamaha adjusters.
the rest of the valve train should be OK , if you use good valves and spings
Thx
So 14mm cams wear out same as 12mm?
Adjusters wearing is possibly symptom of cam worn out.
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I agree with much of what's been said.
I reckon poor materials is a big part of the problem with the cam (12 and 14mm) not so much the design. What are the cam and followers made of? If poor quality steel is the problem has anyone thought about having a cam and followers made?
This is what I'm thinking - pull the stock 12mm cam and followers as a pattern and have a chilled iron (or other durable material) cam and followers made by a specialist. Add to my existing one piece stainless valves w/lash caps.
My machine has stainless steel one piece valves with machine matched guides and Suzuki GN250 springs. Might change the springs if I upgraded the cam and followers.
Would this work or would it trash the pushrods or some other component?
Whadya think :grin:
Cheers
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I reckon poor materials is a big part of the problem with the cam (12 and 14mm) not so much the design.
I'm not so sure of that. Back in the day, MegaCycle made cams for the Lario, and they failed, too. I still don't think anyone has the definitive answer.
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I've seen some big block camshafts that have the oil feed modded so it comes out on the lobes themselves....maybe this could also be done one the small block ones ????
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I've seen some big block camshafts that have the oil feed modded so it comes out on the lobes themselves....maybe this could also be done one the small block ones ????
My understanding is that MegaCycle did that..
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Maybe Larios need to be "rollerized". :wink:
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Maybe Larios need to be "rollerized". :wink:
I've heard of worse ideas. <shrug>
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Maybe Larios need to be "rollerized". :wink:
Should only be a few weeks to see roller tappets in new v85, possibly worth waiting for, would cost a lot to make one offs. Of course, case may be radically different and not fit anyway.
Other possibilities include modding oil feed to camshaft.
However it goes afaik camshaft/ valve tip etc wear is intrinsically linked to valve dropping issue.
Fix main issue first, if I can, proper head scratching going on in oz.
If anyone in world has a high mileage, used hard sb4v, I'd love to see pics of tappets.
Used hard important, treated like heron head v7 they will last same.
Think I got sucked in a few years ago, esp Mike Wrenn's late v7 with 4v heads, all made sense at time.
Staring at bits in front of me, not so much.
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Staring at bits in front of me, not so much.
As Super Chicken says:
You knew the job was dangerous when you took it.. :grin:
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As Super Chicken says:
You knew the job was dangerous when you took it.. :grin:
Even super chickens know flying is the easy part, it's staying up that bothers them and me
I agree with much of what's been said.
I reckon poor materials is a big part of the problem with the cam (12 and 14mm) not so much the design. What are the cam and followers made of? If poor quality steel is the problem has anyone thought about having a cam and followers made?
This is what I'm thinking - pull the stock 12mm cam and followers as a pattern and have a chilled iron (or other durable material) cam and followers made by a specialist. Add to my existing one piece stainless valves w/lash caps.
My machine has stainless steel one piece valves with machine matched guides and Suzuki GN250 springs. Might change the springs if I upgraded the cam and followers.
Would this work or would it trash the pushrods or some other component?
Whadya think :grin:
Cheers
First, measure the lift you have with cam now, dial gauge on rocker over pushrod
Report back also pics of your lash caps/ adjusters
Where did valves come from ?
If they were uk made g & s, all i ever bought from them were nitrided, as they should be
But interested in yours anyway, hope they are 21/4N, do you know ?
not sure you need the stiff original valve springs , the valves are lighter, the rockers heavier but there are two sets of springs operating one rocker.
the original lario valves were made from some steel , and were magnetic current guzzi valves are stainless, only the hardened tip at the top is magnetic
Oe valves i have here are 2 piece, stainless head with ferro shaft
Magnetic right the way to head
Can you tell me where ss valves with hard ferro tips came from ? I would use these
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Oe valves i have here are 2 piece, stainless head with ferro shaft
Magnetic right the way to head
Can you tell me where ss valves with hard ferro tips came from ? I would use these
stein dinse: bought a couple of weeks ago.
https://www.stein-dinse.biz/Moto-Guzzi/Engine/Valves-guides-springs/Exhaust-valve-24-0mm-V65-Lario::8677.html (https://www.stein-dinse.biz/Moto-Guzzi/Engine/Valves-guides-springs/Exhaust-valve-24-0mm-V65-Lario::8677.html)
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stein dinse: bought a couple of weeks ago.
https://www.stein-dinse.biz/Moto-Guzzi/Engine/Valves-guides-springs/Exhaust-valve-24-0mm-V65-Lario::8677.html (https://www.stein-dinse.biz/Moto-Guzzi/Engine/Valves-guides-springs/Exhaust-valve-24-0mm-V65-Lario::8677.html)
Thx, look to be nitrided too, will get this week
Are inlets same, just ferrous tip ?
Don't suppose you've had them long enough to see if tip shows any wear ?
Valves in CiI engine worst wear I have ever seen, valve tips, adjusters and lash caps. all toast
But cam worn to nothing prob explains, super chicken before egg or somesuch.
Keeping the cam egg shaped is the big ask,
tell me story of v75, all I have ever heard is they dropped valves immediately, one apparently straight from pdi / handover. That goes against what I see in these Lario engines, cam is first man out the door, valves follow like sheep.
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i was going to change the exhaust valves as a precaution , so did not order inlet valves.
never seen those fail anyway.
i already run these valves in the lario, the current exhaust valves have no real wear on the tops , and are run without lash caps
i might try elefant foot adjusters to reduce side loads on the valves
the vespa scooter adjusters look promising, just not sure the threads match the lario rockers.
the valve train of the lario and V75 is pretty identical, they had the same issue's
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i was going to change the exhaust valves as a precaution , so did not order inlet valves.
never seen those fail anyway.
i already run these valves in the lario, the current exhaust valves have no real wear on the tops , and are run without lash caps
i might try elefant foot adjusters to reduce side loads on the valves
the vespa scooter adjusters look promising, just not sure the threads match the lario rockers.
the valve train of the lario and V75 is pretty identical, they had the same issue's
I'm onto the ktm elephants feet, should see one this week
250/400/450/520 etc etc all use same thread
Wil post part number when I know, also how much room, may need rocker pedastial lifting ?
Post if you find vespa ones too, may even be same part diffrent price
But did v75 wear cam to nothing quicker than v65 ?
More important, did they drop valves without wearing cam ?
As I'm studying bits, it's the camwear that drives all the other issues.
Light valve springs in mine & chuck's did nothing to save
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i was looking at these
https://ves-parts.com/02-klepstelbout-vespa-etlxlxvs-p-2232.htm
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8V's use similar adjusters. They come with two different thread pitches, not sure offhand what they are but they simetimes cause consternation if the correct pitch isn't chosen. Check the pitch on the Lario.
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8V's use similar adjusters. They come with two different thread pitches, not sure offhand what they are but they simetimes cause consternation if the correct pitch isn't chosen. Check the pitch on the Lario.
Lifesaver Pete, thanks don't know how I missed that from all photos of 8v rocker gear you've posted
6mm x 0.75
If they survive follower failure on BB, they have proven worth. In sickness and in health !
If you have please post me some to check
Even if thread different, rocker arm may be modifiable
Repaid in beer on maiden run to spag, will detour extra few hundred miles to go via bungendore if you're not going. Doesn't hurt my detruction test either. Thing will sink or swim, never ever float around in some mediocre fashion.. fly or crash
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Pete
One more thing to measure if you have a chance
Roller tappets, just occurred to me v85 may not have reinvented itself without a little help from bb 8v
Might be way off but if there is room to fit between centres, these could be the answer
Have cases/ barrels on bench, magicians not far away i
Thanks
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I'll have a dig. Early adjusters have a lot in the top for adjustment. Later ones a 3mm Allen hex. As mentioned they have different threads.
WRT the roller tappets I'd be very, very surprised if they use a different tappet, at least dimensionally, in the V85. It simply wouldn't make sense. Somewhere in Michael's shed there is a cracked cambox off the 1400 that's going in my Stelvio I'll send the entire cambox down as it's easier to see how the whole tappet is aligned with a guide roller if you have the cambox to examine with everything in-situ.
I have early adjusters I think. Not sure about later ones although the 1400 rockers are later type. Be patient please as since Michael's crash I'm not only busy but as far as his workshop is concerned I'm flying pretty much blind so the bits will take a bit of digging out.
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I'll have a dig. Early adjusters have a lot in the top for adjustment. Later ones a 3mm Allen hex. As mentioned they have different threads.
WRT the roller tappets I'd be very, very surprised if they use a different tappet, at least dimensionally, in the V85. It simply wouldn't make sense. Somewhere in Michael's shed there is a cracked cambox off the 1400 that's going in my Stelvio I'll send the entire cambox down as it's easier to see how the whole tappet is aligned with a guide roller if you have the cambox to examine with everything in-situ.
I have early adjusters I think. Not sure about later ones although the 1400 rockers are later type. Be patient please as since Michael's crash I'm not only busy but as far as his workshop is concerned I'm flying pretty much blind so the bits will take a bit of digging out.
Mucho grarcias
Agree, why reinvent, guide should be doddle
Fingers crossed this is the answer to all, no need to nitride or dlc cam, if fact if it works I reckon I can get fkd 12mm cams buit up with stellite, grind a proper grind, let some ponies free
Rollers can deal with big bumps, swhy queen sits in one on potholed London roads !
Elephant's feet will cure the valve drop, I think, scars on valves and adjusters are telling me a story.
Feel like a kid waiting for xmas
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You know that flat and roller tappets require completely different profiles? If I just send down a cambox complete you could start with the current 8Vprofile as a starter if you graph it or take it to a grinder with the ability to custom form a master.
It's not probably the best profile for anything but mapped up, (Or jetted for you Luddite!) correctly it can and does deliver a very nice midrange punch. Scale up or down to suit.
My guess is that the V85 will essentially follow this trend although I expect it to be an interim motor if Guzzi continues to follow precedent and I can't see the spivs in charge of the current project moving far outside the box.
Pete
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You know that flat and roller tappets require completely different profiles? If I just send down a cambox complete you could start with the current 8Vprofile as a starter if you graph it or take it to a grinder with the ability to custom form a master.
It's not probably the best profile for anything but mapped up, (Or jetted for you Luddite!) correctly it can and does deliver a very nice midrange punch. Scale up or down to suit.
My guess is that the V85 will essentially follow this trend although I expect it to be an interim motor if Guzzi continues to follow precedent and I can't see the spivs in charge of the current project moving far outside the box.
Pete
The fun is in doing it first, please do send cambox complete, have man very close who knows more about cams than most, developed all for modern cars, loads of race stuff
He can make master from bb one, modify as needed or go proper mental, give me 12k peak !
Not sure if you have latest details, pm sent address etc
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I am watching this tread with interest.
I have a Lario that I saved from a wrecker due to dropped valve.
I took the heads to a Brisbane based cylinder head guru and he was not impressed with the design.
He reckons there were lots of issues with the design.
Spark plug placement and lots of alloy shrouding it and shit porting on both intake and exhaust.
Closing pressure on the valves was over the top with the standard springs.
Anyhow I put it back together using a set of IceBlue's valves, Lash Caps, Yamaha Adjusters, Nevada Springs.
We did a quick clean up of the ports to suit the standard 30mm Dellortos and manifolds.
It runs standard Lario pushrods and a 14mm cam. It also has a Dyna S ignition system and Enduralast charging system.
I have done about 5,000 klm on it since the rebuild and so far so good.
Its a great bike to ride. I have not exceeded 8,500 rpm so far.
I am in the process of building up a PX750 motor to go into a modified Lario frame.
For this motor I have used ceramic thermal dispersant coatings.
I have two sets of heads for it.
One set is much modified by the Bribane cylinder head guru with bigger valves, better springs, much porting and 34mm carbies.
The second set of heads are set up for the Stein Dinse valves, lash caps, Yamaha adjusters etc.
This motor also has a 14mm cam and I will be running a Ignitech ignition and Enduralast charging system.
Both motors run a 2 into 1 exhaust.
I am very keen to share my findings and learn of others discoveries on these PT and PX motors.
Cheers
Bruce K
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I am watching this tread with interest.
I have a Lario that I saved from a wrecker due to dropped valve.
I took the heads to a Brisbane based cylinder head guru and he was not impressed with the design.
He reckons there were lots of issues with the design.
Spark plug placement and lots of alloy shrouding it and shit porting on both intake and exhaust.
Closing pressure on the valves was over the top with the standard springs.
Anyhow I put it back together using a set of IceBlue's valves, Lash Caps, Yamaha Adjusters, Nevada Springs.
We did a quick clean up of the ports to suit the standard 30mm Dellortos and manifolds.
It runs standard Lario pushrods and a 14mm cam. It also has a Dyna S ignition system and Enduralast charging system.
I have done about 5,000 klm on it since the rebuild and so far so good.
Its a great bike to ride. I have not exceeded 8,500 rpm so far.
I am in the process of building up a PX750 motor to go into a modified Lario frame.
For this motor I have used ceramic thermal dispersant coatings.
I have two sets of heads for it.
One set is much modified by the Bribane cylinder head guru with bigger valves, better springs, much porting and 34mm carbies.
The second set of heads are set up for the Stein Dinse valves, lash caps, Yamaha adjusters etc.
This motor also has a 14mm cam and I will be running a Ignitech ignition and Enduralast charging system.
Both motors run a 2 into 1 exhaust.
I am very keen to share my findings and learn of others discoveries on these PT and PX motors.
Cheers
Bruce K
Hey Bruce, best feedback I have seen since all builds of 5 years ago.
Definitely keep comparing notes, all I have is worn bits, be first time I actually built one.
What I don't know is how long it take cam/followers to start breaking dowm, or even if it is just an oil thread, no zinc on flat tappets blah blah.
Rollets, if I can make them fit, should take that part out.
As you say, many other things to do to make them work but I am doing first gently to prove, also have two engines, second will be more, but I'd like 10k km looksee on #1 before actually testing #2
Very interested in your headman, did he measure spring pressure ?
My engine with Nevada springs has caps/collets I could not use, collets stick out a mile
Do you know which caps you used ?
Also installed height, I will need a bit more pressure with weight of rollers but also trying to get rockers to spin freerer so may not be far off.
Same for your springs with big valve, pressures, at installed height and full lift
Caps with them ? Availability from your man ?
My best help in this is cam genius, if we can be certain we have solved cam wear and valve dropping I'll go with his ideas, he has done this a lofetime, now sold business and retired but can't stop getting his hand's dirty, loves a problem.
I can see a sb4v aus owners group meeting coming up, hope both of us make it there !
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The fun is in doing it first, please do send cambox complete, have man very close who knows more about cams than most, developed all for modern cars, loads of race stuff
He can make master from bb one, modify as needed or go proper mental, give me 12k peak !
Not sure if you have latest details, pm sent address etc
Only issue I can see is getting the pushrod located on the top of the tappet in the block. The 8V's use a hemispherical 'Pad' on top of the tappet shaft that engages in the rocker. The top of the tappet tower is flat. This will obviously be a non-starter with a pushrod arrangement. I'm imagining the V85 will have some sort of 'cup' on top of the tappet for pushrod engagement?
If you're hoping to see 12K out of it you'll be needing to beef up the rods big time or they'll snap like rotten carrots! What will the MEPS be at 12?
PS. Found a cambox off the 1400 and am waiting for info from Michael on the whereabouts of a set of earlier rockers. I have a later adjuster, can't find my thread gauge but it looks like it might be 0.5mm. Earlier ones are coarser so might be 0.75. As soon as it's all together I'll post it off. Please don't loose any of the bits.
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Only issue I can see is getting the pushrod located on the top of the tappet in the block. The 8V's use a hemispherical 'Pad' on top of the tappet shaft that engages in the rocker. The top of the tappet tower is flat. This will obviously be a non-starter with a pushrod arrangement. I'm imagining the V85 will have some sort of 'cup' on top of the tappet for pushrod engagement?
If you're hoping to see 12K out of it you'll be needing to beef up the rods big time or they'll snap like rotten carrots! What will the MEPS be at 12?
PS. Found a cambox off the 1400 and am waiting for info from Michael on the whereabouts of a set of earlier rockers. I have a later adjuster, can't find my thread gauge but it looks like it might be 0.5mm. Earlier ones are coarser so might be 0.75. As soon as it's all together I'll post it off. Please don't loose any of the bits.
Ta
Will show all to cleverer man than I, nothing is impossible only cost thereof might outweight value
12 is for nuther day, maybe, for now safe 8500 forever would be sweet.
Just trying to put the pin back is all
If pad that works rocker not in it, just send me pic or link to on here , bet you've posted it altready
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So here's some stuff from Moto Guzzi Club GB magazine 1990, written by Simon Howers. He bought a 4 valve V75 brand new in 1986 and sorted it out with help from Raceco (UK); the aim being to make it reliable up to 10 000RPM. Not sure the overrevving/coil bound spring issue has been raised here before?
- On strip down the cam and followers were stuffed after 3000 miles with serious damage to the lobes
- Guzzi fitted a single coil spring that which at full valve lift is within 1mm of being coil bound
- ...not only that but each spring requires about 50kg to depress it
- the springs have two effects, they place incredible strains on the cam lobes and secondly a slight overrevving of the engine would cause them to slam open, and break the head off the valves
- Larios have the same problem and show alarming signs of wear after about 20000 miles.
A new standard cam was fitted with Kawasaki 500/4 springs. His view is either cam is fine and the springs are the problem, the later 14mm cam is a Guzzi bodge.
I followed up with him last year and the bike was reliable and fast for (IIRC 30 000) miles and still is (with a different owner)
HTH
Cheers
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I followed up with him last year and the bike was reliable and fast for (IIRC 30 000) miles and still is (with a different owner)
HTH
Cheers
amazingly my lario survived 40.000 miles with the stock valvetrain,
after the first engine dropped a valve i fitted a spare engine ( with soft springs and stainless valves. )
that one is going fine too ( probably close to 40,000 miles on it too, but so was the original engine )
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So here's some stuff from Moto Guzzi Club GB magazine 1990, written by Simon Howers. He bought a 4 valve V75 brand new in 1986 and sorted it out with help from Raceco (UK); the aim being to make it reliable up to 10 000RPM. Not sure the overrevving/coil bound spring issue has been raised here before?
- On strip down the cam and followers were stuffed after 3000 miles with serious damage to the lobes
- Guzzi fitted a single coil spring that which at full valve lift is within 1mm of being coil bound
- ...not only that but each spring requires about 50kg to depress it
- the springs have two effects, they place incredible strains on the cam lobes and secondly a slight overrevving of the engine would cause them to slam open, and break the head off the valves
- Larios have the same problem and show alarming signs of wear after about 20000 miles.
A new standard cam was fitted with Kawasaki 500/4 springs. His view is either cam is fine and the springs are the problem, the later 14mm cam is a Guzzi bodge.
I followed up with him last year and the bike was reliable and fast for (IIRC 30 000) miles and still is (with a different owner)
HTH
Cheers
Thanks, actually sent Amadeo an email recently when I was in uk, asking if he had ss lario valves but no reply. He used to buy ss valves for bb from/with me, together we bought enough to get price right. I never wanted to play Lario then, 30 years have changed me.
Still don't know if had lario ones made, vague memerry says yes.
Agree with all, valve spring pressure tester on my horizon but first I want roller tappets.
Part number for these springs would be handy
My lario has 80k km on clock but know it blew once before, I think cam never changed, expert fixed cause maybe but ignored major symptom
Maybe catch up uk next summer ? Would like to see this v75 but picture of valve gear would tell all, if no wear on valve tips/adjusters we have to say this one was fixed.
Assuming it has been given berries for 30 years of course, 10k rpm is working
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expert fixed syptom, ignored cause.
This is not the first expert that has done that. And that is strictly *not* inclusive to motorcycles.. <shrug>
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This is not the first expert that has done that. And that is strictly *not* inclusive to motorcycles.. <shrug>
Sorry chuck I modified that as you were replying, he may have fixed cause but not one of symptoms
There are a few symptoms here, valve dropping the one in title, but cam is up there.
Mud is clearing, a plan is forming, when I get Pete's rollers I will know more
Might paint it tartan
Bye bye baby baby bye bye................ ..
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amazingly my lario survived 40.000 miles with the stock valvetrain,
after the first engine dropped a valve i fitted a spare engine ( with soft springs and stainless valves. )
that one is going fine too ( probably close to 40,000 miles on it too, but so was the original engine )
Read most of this string. I think what huub here relates is very descriptive of the Lario "issue". Having read a lot of report on when Lario drops valves point to more than one culprit IMHO. Some PX and PT mills only did a few thousind miles/KM before destroying cam lobes and dropping valves. Others did like 40-60.000.
The jury is still out, but a few pointers seems certain.
The PX and PT - or any other SB design was never intended for 8V operation. So the design is certainly not in favour of the valve train design of the 8V's. To make sure the mills would sustain hefty over revving, very stiff springs were used. About the same strength as the double spring of the early 4V SB's. NOW - some SB's with these double springs also occasionally dropped valves. The cam lobe here only had to lift ONE such stiff spring. Imagine - in the PX and PT engines the cam lobe had to lift TWO such springs initially on a 12mm lobe. In the late 80's Guzzi started using the progressive spring, and recommended all double springs replaced with this new spring at the same time Guzzi introduced the 14mm lobe CAM with that spring on all subsequent SB's. To my knowledge valve drops on 4V SB's totally vanished after that. I think they'll have a similar effect on the PX and PT 8V mills, although the lobes on the 8V's will have to lift TWO progressive springs.
I do not think this makes the PX and PT's bullet proof!! ...but I think it helps. IMHO, the following facts has a say in the problem.
- Quality of the material used to produce the camshaft and followers. (The huge variation in millage in when cam lobes are flattened - even on the same cam shaft - one seemed almost untouched - another basically flattened)
- Quality of the valves
- The VERY stiff stock spring - I swear by the V7/Nevada progressive spring - but this will limit the RPM to the red line - NO over revving
- The overall design of the modified valve train to accommodate 4 valve heads instead of two valve heads
- Oil used - make sure it has the ZDDP needed for flat tappet mills
- Cooling design of the heads - I'm not convinced though…
If you want to secure the PT and PX mills to the maximum level - wearing both belt and suspenders - but staying with the stock geometry of the train and still throw in the bucks it takes, I'd assume the following:
- Progressive V7 Classic/750 Nevada spring assembly
- One piece valves - pricy but needed
- Yamaha clearance screws - larger "face" hitting the valve stem/cap
- The later 14 mm lobe cam shaft
- Possibly DLC coated tappets and CAM - I don't know much about this procedure - some are not happy about the risk of diamond wear dust in the oil
- Good quality stem caps if required by the valve quality/design, to avoid mushrooming the stems
- Oil with adequate ZDDP for flat tappet mills
- Oil bush between cylinder and head - drilled to 2mm - stock 1mm - controls oil flow to the head and valve rockers. Oil also helps cool the head
The PT and PX will likely still not be bullet proof - but from what I learn "around the block" it helps a lot.
The adaptive design of the 8V valve train in the PX and PT mills will always leave one nail in its coffin.
One of my Lario's now has 18.000km on the clock with the progressive V7 spring and the 14mm cam.
Pulled one cylinder this summer to check the cam lobes, clearance screws and stem caps.
It all looked like the day I upgraded the mill - only just visible wear on the caps and clearance screws.
The Lario is one fun bike! - makes it acceptable with a slightly earlier expiration date on the mill if its number is up :boozing:
Ciao
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Brian
I spent a long time measuring and checking before putting mine together, the important part is not which brand springs you use it is setting them at correct height / pressure.
Avoiding coil bind, of course
I also had to grind rockers for clearance and shorten pushrods to fit elephant feet adjusters
new oe. alves are fine imho
infact mine is all std except valve springs and adjusters
just a bit of love in assembly
this one is a hooter, thrashing it mercilessly every day. no rev limiter on std points ignition
i lit the fuse, any bets on result?
will prob see 10k miles over summer, all on the noise
Then the hot one goes in
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Brian
I spent a long time measuring and checking before putting mine together, the important part is not which brand springs you use it is setting them at correct height / pressure.
Avoiding coil bind, of course
I also had to grind rockers for clearance and shorten pushrods to fit elephant feet adjusters
new oe. alves are fine imho
infact mine is all std except valve springs and adjusters
just a bit of love in assembly
this one is a hooter, thrashing it mercilessly every day. no rev limiter on std points ignition
i lit the fuse, any bets on result?
will prob see 10k miles over summer, all on the noise
Then the hot one goes in
I *love* the character of the Lario engine. That rush to redline is addictive. :thumb:
Attaboy, Martin.. hopefully you have it finally sorted.
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Brian
I spent a long time measuring and checking before putting mine together, the important part is not which brand springs you use it is setting them at correct height / pressure.
Avoiding coil bind, of course
I also had to grind rockers for clearance and shorten pushrods to fit elephant feet adjusters
new oe. alves are fine imho
infact mine is all std except valve springs and adjusters
just a bit of love in assembly
this one is a hooter, thrashing it mercilessly every day. no rev limiter on std points ignition
i lit the fuse, any bets on result?
will prob see 10k miles over summer, all on the noise
Then the hot one goes in
You may very well be right on all counts.
I'm taking the chance too on two piece standard valves, my list was more in the direction of making it as bullet proof as possible - here I believe one piece valves are safer.
As to the spring, here again you may be right, however, Guzzi's own progressive SB springs has served me VERY well. Also recommende by Guzzi for the 2V heads - the 2V valve train use the same cam shaft as the PT and PX mills, same stems width on the valves etc. Best of all, I haven't seen any cam lobe wear after 18.000 km. So far it's still my choice for the Lario valve train mod., but time will show. As I said the jury is not in yet.
I have hit 9000rpm by accident on mine, but I heard valve float - not healthy, and with the spring I use, it sets in at red line.
Yes Chuck - the takeoff :whip2: to red line is addictive :drool:
Lots of SB's to choose from, but I almost always end up on the Lario.
Ciao
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You may very well be right on all counts.
I'm taking the chance too on two piece standard valves, my list was more in the direction of making it as bullet proof as possible - here I believe one piece valves are safer.
As to the spring, here again you may be right, however, Guzzi's own progressive SB springs has served me VERY well. Also recommende by Guzzi for the 2V heads - the 2V valve train use the same cam shaft as the PT and PX mills, same stems width on the valves etc. Best of all, I haven't seen any cam lobe wear after 18.000 km. So far it's still my choice for the Lario valve train mod., but time will show. As I said the jury is not in yet.
I have hit 9000rpm by accident on mine, but I heard valve float - not healthy, and with the spring I use, it sets in at red line.
Yes Chuck - the takeoff :whip2: to red line is addictive :drool:
Lots of SB's to choose from, but I almost always end up on the Lario.
Ciao
from my experience measuring 3 motors the installed height is crucial to measure
you may only have one valve bouncing
heads I had that were supposedly fixed varied hugely, pot luck if springs alone are enough
good that cam still measures true, my check is just measure lift at pushrod , no need to take apart until wear shows on dial gauge
only bad thing mine does is tingle at bars will balance crank on next, bbut not a biggie
btw new oe ex valves are ss
inlet still 2 piece but no concern imho