How to not enjoy the ride so much

[rodekyll]

It is a nice ay in Alaska.  I decided to head out to al the ends of the road.  On the way outbound I stopped at the store for mustard and sour cream, on account of my herring pickle is ready to pack.  Leaving the store I heard and felt an odd scraping sensation -- kinda like lightly dragging the kickstand when you shouldn't ought to.  I looked down -- nope.  Stand up.  I checked my gauges.  Everything looks normal on the engine side.  Flipped the switch for tranny properties and got no pressure.  Flipped back -- engine oil good.  Flipp to tranny -- nothing.  Then 5# . . .3# . .5#.. .nothing.  Crap.  The noise and skritchy feeling must have been the Convert ATF drivepiece going from hex to round.  I hate it when that happens.

With two miles to go back to the barn I had a choice -- try to drive it and risk the embarrassment of losing automotion in traffic (or worse -- losing automotion accompanied by clouds of pink smoke), or return to the store parking lot and get a flatbed.  Since I'd watched the last of the pressure twitch out of the gauge, I felt I had the two miles before the atf failed.  I did.  Exactly.  I got it to the driveway, but didn't have enough left to go up the gentle slope to the carport.  I had to get off and walk it up.

Now I have to pull the stupid timing cover and cut down another allen wrench.  That's another two hours gone from my life.  I just broke a ball-headed one in a CV joint.  Brittle may mean hard metal.  Maybe I'll use it.   **C

[oldbike54]

 Is the timing cover naturally unintelligent , or is it learned behavior ? ;D

  Dusty

[rodekyll]

It's a give and take thing -- we school each other.  I teach it to tell me when it's breaking again, and it shows me how to do the fix more quicker each time.   :beat_horse

[rodekyll]

It's the most horrible upgrade to an originally terrible design I've encountered on a Guzzi.

[balvenie]

            Allen wrench; made in China? One I had came in an Uncle Mike's kit. Twisted like a piece of cheese :o

[fotoguzzi]

would a stainless steel hex be stronger?

[rodekyll]

No, stainless is generally soft stuff  -- inferior in stressful situations.  I don't think they'd make a hex tool out of it.

[lucydad]

Rode,

Dang...its one of those Alaska things.  Had an old Jeep do that to us on the Dalton highway back in 83.

Wish I could fly up, and help you fix it meanwhile be your general morale support and supplier of expensive, but good adult beverages.

Sheesh...but spring is coming!

[rodekyll]

In the Great Land, spring done springed.  We've had two days in a row of 50s and sun.  That beats the old record by two days!

I got about 5 years and two backfires out of that drivepiece, so I'm not complaining other than I always complain when this happens.

The moral of the story is that I was two miles out from the barn when the shaft failed, and I had two miles before the atf fried and the bike wouldn't go anymore, which is the worst thing that can happen to a 'vert.  If I had not had a pressure gauge on my atf line I would have continued outbound and failed 4 miles from home instead of making it back to the toolbox.  So my silly overengineering saved my day.   8)

[Muzz]

Still a sh*t sandwich thing to happen to you.

Great to see you made it home. Always awkward when things like that happen; worse if it happens out in the boonies.

[rodekyll]

The worst time it happened was about 3 miles in to Bamf Park from the Iriduim side.  Talk about losing it in the dingles!  I pulled it apart by the side of the road on a really hot, dusty, dry day.  It was so hot and dusty and dry that you actually could hear the hawks screeching in the distance, although you couldn't see them through hthe glaring sun.  A lizard took refuge under my alternator cover and got pissed when I'd toss nuts and bolts into it.  We got well acquainted.  A gent on a day-glo yellow GW trike stopped and asked if he could help.  I sent him into town for an allen wrench and a hacksaw.  He tossed me a beer to help pass the time, and retuned a half-hour later with the stuff -- wouldn't take payment.  I was back on the road within three hours of losing it.




LD -- you don't need an excuse to come up.  But if you did, I'd put you to work on the trike.  We're still aiming at the 15th to fire it up.  There's a lot to be done.

[Sasquatch Jim]

  From what I remember, most Laskans are like that.

[BigDave in PA]

Did you ever put the updated pump shaft in it? It's the piece in the pump it self that the allen key goes into. The updated part has a deeper internal hex that the shaft goes in. I put one in my '76 convert and never had the shaft problem since.

[Shorty]

Trying to remember. Didn't someone come up with an external pump system for the Connies?

[Matt Story]

Has someone explored using an alloy tool steel for this piece?  I think stress tolerance and toughness are preferable to hardness.  I'm thinking maybe an alloy by Pennsylvania Steel marketed as Flexor.  It has a high yield strength and is purported to be stress resistant.  Maybe maxing out the hardness is not the best idea.  I am not sure the alloys commonly used for allen wrenches, but I think it would be best to at least cut up a premium brand.

I'd like to talk to a friend who knows a lot more than me about what would be the best material for the job.  Unfortunately, not many materials are available in the hex shape which requires machining.  What is the hex size?

Matt

[rodekyll]

It's a 6mm hex.  One end goes into that drivepiece, and the other lives in a bore in the cam.  We don't want it too hard.  Then it would be the cam bore that fails instead of the hex shaft.  It's easier to find an allen wrench on a trip than a Convert cam.

The problem is that the cam and pump bodies might not be in exact alignment due to mfgr variances.  So there needs to be a tiny bit of misalignment compensation.  Guzzi chose to do that by making a sloppy fit at the forward (drivepiece) joint.  The hex shaft is rounding itself off in the harder drivepiece every time the throttle is rolled on or off.  Snatch at the throttle or use engine braking and the problem amplifies.  Have a nasty backfire and the cam stops and runs backwards momentarily while the pump (under pressure) continues to go its normal direction.  This can spin the shaft in its bores.  In my case it's all of the above.  What I heard and felt was the final ratcheting of the shaft going full-round.

The proper fix would be to make everything a little larger -- 8mm instead of 6, or go to splines instead of hex.


Yes, someone reported that they went to an electric pump.  This was some years ago.  I have my doubts, since he wouldn't give any details, like what pump he used, what the flow and pressure targets were, etc.  Also never reported back on how it worked out for him.  I've looked into it and it's no easy thing to spec.  You're not getting there with a universal 'lectric fuel pump.

It needs to be a
hydraulic fluid pump
capable of withstanding high heat and petroleum/mineral oils 
high flow
relatively low pressure/adjustable pressure limit to 30# 
work at a couple amps or less
12vdc
sized to available space
not contribute to foaming
and of course, affordable

If anyone has one lying on the shelf they want to donate, I'll figure out the plumbing and report back with results.    :bike

[dguzzi]

Would it be something you could make extras and have with you?  I'm not familiar with how deep you have to go to fix it.

[rodekyll]

Yes, I carry an extra with me now.  You have to remove the head pipes, alternator, and timing cover.  The timing cover needs to move away from the engine just far enough to slip the old hex out and the new one in.  If you didn't mess up any gaskets or seals,then simply replace everything and get on with life.  If done on the centerstand you don't even lose oil.  Just some time.