bighairyralph
XS650 Addict
Mine was aluminum with steel tips too.
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'81-Build Thread-The Handover
- Thread starter littlebill31
- Start date
The middle rod on the 2 piece set-ups was mostly aluminum, but with steel tips. No doubt this helped with the heat expansion = more freeplay problem. I don't know why Yamaha just didn't make one long rod like that. They did for the XS360/400/500. I just don't understand their "thinking" here.
littlebill31
Smells of Raw Fuel
Huh. My other '81 has two pice steel as did the one I had several years ago. Interesting.
The clutch was extemely hard to pull on this bike, so Im sure it has to do with the bent rod.
The clutch was extemely hard to pull on this bike, so Im sure it has to do with the bent rod.
If you clean them off and look closely, you'll see the center rod is "bi-metal" - aluminum with steel ends. 2M actually made new ones, one piece and bi-metal. But, I don't think the few thousandths we gain or lose here makes the difference we really need. We need a worm gear that pushes the plates apart more, one that has more "travel". There could be one from another bike somewhere, we just need to find it.
Hmmmm - I can't see why that rod wouldn't be steel. I can certainly see the dimples on each end to help centre the balls - but the part hardly moves, it doesn't rotate and so saving a few grams of weight on a part that it is as important as this one seems odd.
Pete, its because of the different expansion of aluminum and steel. The aluminum engine expands more than the steel pushrod, which results in a large amount of free play at the clutch lever. The clutch will work fine when the engine is cold, but as it heats up, the amount of clutch plate separation get smaller, and it becomes difficult to shift into neutral. One of the pushrods being aluminum is an attempt to match up the expansion. It does help some, but it is still a problem on these bikes.
I drilled an additional hole in the worm gear operating lever, which gives a longer stroke to the pushrod. I changed my stroke from
0.079" to 0.097" and that works much better, as I can find neutral most of the time. I use the one piece steel pushrod.
Interesting - that may be the case RtdGent but doesn't the push rod run through the primary driven (I.e. clutch) shaft - which would be steel?
The presence of aluminium and steel in the engine - and their widely differing coefficients of thermal expansion is the reason why the shafts in motorcycle engines - and other pieces of machinery - are normally mounted with a roller bearing in an axially fixed arrangement on one end and a ball bearing that is able to move axially, on the other end. As the aluminium engine cases expand and contract more than the steel shafts, the bearings can slide in the cases to compensate.
Back to the clutch rod: it seems to me that the only aluminium in the load path is that portion of the left side engine case between the centre engine cases and the pad where the clutch worm actuator is mounted. I suppose that portion of the load path that is aluminium could expand enough to require an aluminium rod - but I wouldn't have though it would get hot enough to require such a measure.
Anyhow, a very interesting discussion which really illustrates the sort of engineering issues involved designing and building a machine of the complexity of an internal combustion engine.
Thanks for the note!
Pete
The presence of aluminium and steel in the engine - and their widely differing coefficients of thermal expansion is the reason why the shafts in motorcycle engines - and other pieces of machinery - are normally mounted with a roller bearing in an axially fixed arrangement on one end and a ball bearing that is able to move axially, on the other end. As the aluminium engine cases expand and contract more than the steel shafts, the bearings can slide in the cases to compensate.
Back to the clutch rod: it seems to me that the only aluminium in the load path is that portion of the left side engine case between the centre engine cases and the pad where the clutch worm actuator is mounted. I suppose that portion of the load path that is aluminium could expand enough to require an aluminium rod - but I wouldn't have though it would get hot enough to require such a measure.
Anyhow, a very interesting discussion which really illustrates the sort of engineering issues involved designing and building a machine of the complexity of an internal combustion engine.
Thanks for the note!
Pete
Sorry - hit send too fast.
I do like the notion of drilling an extra hole in the link on the clutch to increase the axial travel of the clutch mechanism. The '76 works well, but I may very try that on the '81 once I get it running.
Cheers,
Pete
I do like the notion of drilling an extra hole in the link on the clutch to increase the axial travel of the clutch mechanism. The '76 works well, but I may very try that on the '81 once I get it running.
Cheers,
Pete
Pete.....................I'd be glad to give the details of where I drilled the new hole in the arm, if you ever go that way. Put some kms on the bike and see how you find the clutch operation. Its quite easy to pop off the left side cover and drill a new hole.
Thank RG - will do.
Pete
Pete
littlebill31
Smells of Raw Fuel
I'd be for the additional drilled hole info. My other bike, the one I ride the most, has a real problem keeping the clutch adjustment correct. Worst I've had. It has a nice smooth pull, but after 45 minutes or so, I'm adjusting the perch like mad.
member3480
RICH
Hey that's a new good job for you on those cases . I got 4 that need to be done LOL
littlebill31
Smells of Raw Fuel
Lol, ya, my fingers are raw. Going to be a while before I do that again. Luckily my '79 (which is next) has a clean engine. No spray paint.
Great work and a great thread, Bill. There's a lot of fine how-to here, and you've written the piece in a way that provides a lesson on things to think about and look for before exchanging cash for motorcycle. A read through this thread could save a lot of folks a lot of grief.
My stock operating arm was 1.78" from centre of worm to centre of hole in arm. I drilled a new hole so it became 1.49".
5twins do you have a measurement of the late arm?
Of course, there is a slight penalty, in that it will require a little more strength in your left hand to operate the clutch.
5twins do you have a measurement of the late arm?
Of course, there is a slight penalty, in that it will require a little more strength in your left hand to operate the clutch.
littlebill31
Smells of Raw Fuel
Thanks, Grizld.
One thing I hope many will understand, and think about, is that I have spent a good deal of money and time in order to get this bike operational again. And I mean stock in operation. Nothing I have done is aftermarket in nature. I did trim some from the frame, but as for the engine, its all reconditioning to be a safe and solid ride.
So I warn anyone buying a bike to make sure it is all good to go and repaired before adding aftermarket parts or "upgrades". Just look at my old pistons.
One thing I hope many will understand, and think about, is that I have spent a good deal of money and time in order to get this bike operational again. And I mean stock in operation. Nothing I have done is aftermarket in nature. I did trim some from the frame, but as for the engine, its all reconditioning to be a safe and solid ride.
So I warn anyone buying a bike to make sure it is all good to go and repaired before adding aftermarket parts or "upgrades". Just look at my old pistons.
Guys, with all respect, too many posts about side issues like clutch actuator bits and mods will distract from the very valuable main points of this thread. That's a fine discussion, but how about taking it to a new thread?
littlebill31
Smells of Raw Fuel
As I am waiting for some parts for my engine I worked on cleaning the lower fork tubes.
First go around with 600 wet sand
First go around with 600 wet sand
Looks nice littlebill!
