Does Radial Clutch Play = Clutch Spline Wear????

[rxcrider]

Clearly a couple different schools of thought, but just two sides of the same page I think. At the end of the day, you are venturing into little known territory using that shaft combined with the spacer. Keep your fingers crossed and an eye on the wear. Hopefully you'll get a good extension on the input spline life without dropping a bunch on parts.


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[nrpetersen]

Clearly a couple different schools of thought, but just two sides of the same page I think. At the end of the day, you are venturing into little known territory using that shaft combined with the spacer. Keep your fingers crossed and an eye on the wear. Hopefully you'll get a good extension on the input spline life without dropping a bunch on parts.


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Well stated. Frankly there is no warranty.

 

[cele0001]

With the spacer installed there is more contact surface between hub and splines on a worn shaft then there was on a new shaft with partially engaged hub.
It is now stabilized on both edges of the hub. It is good.

EDIT: Go ride and enjoy the work. Beat the hell out of the clutch.
Lots of angry downshifts and upshifts. You bought the bike, not the other way around.

 

[dagear]

Thanks for all the feedback

Can the discussion about worn input shaft on the 1150 to be made a sticky

 

[rxcrider]

There are so many of these threads, I sort of doubt it. A sticky index of categorized tech threads might be a better option, but somebody would have to own it and edit / update the first post.


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[nrpetersen]

I presume stickies would be appropriate only when then technology is settled.

 

[roger 04 rt]

Spine shaft wear is the "oil thread" of mechanical. Lots of opinions, little data.

 

[roger 04 rt]

With the spacer installed there is more contact surface between hub and splines on a worn shaft then there was on a new shaft with partially engaged hub.
It is now stabilized on both edges of the hub. It is good.

EDIT: Go ride and enjoy the work. Beat the hell out of the clutch.
Lots of angry downshifts and upshifts. You bought the bike, not the other way around.

If I ever have the need to split my bike I will install a spacer. Although the benefits are unproven, I like the idea of a longer, possibly tighter, more stable fit.

 

[pglaves]

Complete engagement rather than partial engagement of the splines has to be positive. The real question is how much spline engagement is enough. The other question is how much misalignment exists and what can be done about it.

Back when K75 bikes were the latest there were a number of cases of very early spline failure. There were some cases of repeat early (low miles) spline failure. On those bikes the bellhousing (auxilliary case) was a separate piece and changing that usually cured the problem. With OilHexCamhead bikes there is no auxilliary case - the engine case is the bellhousing and vice versa. Thus curing a misalignment requires serious machine work, a replacement transmission case, or a replacement engine case. Even accurately documenting and dimensioning the problem would require several hundred dollars for a shop to gut the transmission to make the measurements if they even knew how - which most don't.

In the meantime I firmly believe that relative regular cleaning (to remove any metal grindings) and new lubrication of the splines is worthwhile. It is for me because I do it myself and while it takes time it is cheap. Not quite so much if you hire a shop to do it. So what is a suitable interval. I say 40,000 miles - maybe 50,000 if you regularly win door prizes or ever hit the lottery.

I use a sticky moly grease - not paste - grease! I have mixed Honda Moly 60 with Wurth 3000; I have mixed powdered moly into a sticky grease; I now use Guard Dog 525 which is a very tacky 30% moly grease.

 

[happy wanderer]

With the spacer installed there is more contact surface between hub and splines on a worn shaft then there was on a new shaft with partially engaged hub.
It is now stabilized on both edges of the hub. It is good.

EDIT: Go ride and enjoy the work. Beat the hell out of the clutch.
Lots of angry downshifts and upshifts. You bought the bike, not the other way around.

Having a hard time visualizing how there would be more contact surface than before with the longer hub. Over in your ADV Rider thread you stated: "6 speed has 19 mm of spline length available. It does not use 6 mm, so only 13mm are actually carrying the load. Thank you GSAddic for the info."

So if 13mm of input spline has been badly worn and the spacer now pushes the clutch hub further in toward teh transmission to a maximum of the 6mm remaining, how does that equate to "more contact surface than before"?

In my minds eye I see up to 6mm of brand new clutch hub fully engaging up to 6mm of unused spline. But by doing this the very worn 13mm section is not going to make contact at all if everything is straight. Only when the newly engaged 6mm is worn down to the same point of the original 13mm engagement will there be full contact.

Not sure how to explain it. Think about a nut and 10mm thick bolt. The nut has perfect threads. The first 3mm of the bolt threads are perfect but the rest of them are completely worn out. Screw the bolt into the nut. Is that going to make a solid engagement? I think it will wobble around a bit and might hold for a while but in a very active and high torque situation like a clutch hub... ? I can't see doing this unless both the bolt and the nut were new and mated correctly from the get go.

 

[pglaves]

Having a hard time visualizing how there would be more contact surface than before with the longer hub. Over in your ADV Rider thread you stated: "6 speed has 19 mm of spline length available. It does not use 6 mm, so only 13mm are actually carrying the load. Thank you GSAddic for the info."

So if 13mm of input spline has been badly worn and the spacer now pushes the clutch hub further in toward teh transmission to a maximum of the 6mm remaining, how does that equate to "more contact surface than before"?

In my minds eye I see up to 6mm of brand new clutch hub fully engaging up to 6mm of unused spline. But by doing this the very worn 13mm section is not going to make contact at all if everything is straight. Only when the newly engaged 6mm is worn down to the same point of the original 13mm engagement will there be full contact.

Not sure how to explain it. Think about a nut and 10mm thick bolt. The nut has perfect threads. The first 3mm of the bolt threads are perfect but the rest of them are completely worn out. Screw the bolt into the nut. Is that going to make a solid engagement? I think it will wobble around a bit and might hold for a while but in a very active and high torque situation like a clutch hub... ? I can't see doing this unless both the bolt and the nut were new and mated correctly from the get go.

I think you are visualizing it correctly but from the wrong viewpoint. I don't know the exact dimensions so will simply make up my own to make the point. The OEM configuration only allows the clutch hub to slide partway onto the transmission input shaft. Say only 75% of the way. Now install a spacer which spaces the hub forther rearward from the faces of the clutch disk. So that it engages 100% instead of 75% of the input shaft. You have just increased the spline area of contact by a third - spreading the load and wear over a larger area. What I have just described assumes a new hub and new shaft. If stuff is already worn you are probably just shifting the load to the unworn part that will wear rather quickly until it matches the already worn part.

 

[cele0001]

In my minds eye I see up to 6mm of brand new clutch hub fully engaging up to 6mm of unused spline. But by doing this the very worn 13mm section is not going to make contact at all if everything is straight. Only when the newly engaged 6mm is worn down to the same point of the original 13mm engagement will there be full contact.

I get you point, but the key here is the fact that input shaft is not worn out when the splines fail. The hub is destroyed but he shaft is not, (not fully anyway). The main wear area is only about 5-6mm wide area toward the back. I am sure you have seen the pictures. The front of the shaft is more or less new. So overall we are getting 6mm of new "meat" and front of the shaft will now be used to stabilize the hub. I agree that there is worn area in the middle that will not be used, but IMO benefit of gaining that second point of contact to prevent wobbling from starting in the first place is critical. To appease the "lubrication " crowd (although IMHO lubrication has very little to do with the failure) this middle area would effectively store grease (or paste). So the joint is "self-lubricated" as well.

 

[pglaves]

The photo of the shaft in post #14, this thread, looks to me like there is an angular misalignment between the clutch hub and input shaft. That is, it looks like the clutch housing (flywheel) is bent and thus "wobbles". In the classic K bikes the clutch housing was a stout cast and machined aluminum piece. On the Oilheads it is much thinner steel and rather easy to bend.

The photos also clearly show the "step" in the wear pattern where the shaft is unworn and the hub is unworn because when assembled they don't fully engage.

 

[nrpetersen]

Paul G - Don't get fooled by the curved (spiraled) input spline wear a lot of people do). The disk hub is wearing in a mirror fashion If you study both parts in post 14 above, wear is either in the hub or on the spline shaft. Which, depends on the differential hardness of the parts at any axial location. If there is axial misalignment (i. e. an angle between the engine and transmission axis, it is easily measured, and of comparatively little consequence.

If there is radial misalignment, it requires a full engine clutch pack and transmission dis assembly and a dial indicator sweep from the crankshaft indicating onto the transmission input bearing housing bore. Even then, there may be unaccountable errors depending on the engine main bearing wear. It's hard to measure - but there's a lot of consequence given the radial stiffness of both elements (the engine crank and the transmission input shaft).

Is the clutch housing steel? It looked to me like an aluminum casting. The transmission input bearing bore ID is definitely aluminum.

 

[rxcrider]

...If there is axial misalignment (i. e. an angle between the engine and transmission axis, it is easily measured, and of comparatively little consequence...

How is it easily measured?
______________________

Is the clutch housing steel? It looked to me like an aluminum casting. The transmission input bearing bore ID is definitely aluminum.

Clutch housing = flywheel, not bell housing.

 

[pglaves]

______________________


Clutch housing = flywheel, not bell housing.

Clutch housing = flywheel = steel

 

[nrpetersen]

The photo of the shaft in post #14, this thread, looks to me like there is an angular misalignment between the clutch hub and input shaft. That is, it looks like the clutch housing (flywheel) is bent and thus "wobbles". In the classic K bikes the clutch housing was a stout cast and machined aluminum piece. On the Oilheads it is much thinner steel and rather easy to bend.

The photos also clearly show the "step" in the wear pattern where the shaft is unworn and the hub is unworn because when assembled they don't fully engage.

Guess I've been calling everything that rotates a clutch pack. The bell housing is the part that I contend is guilty of causing radial misalignment. The flex of the rotating clutch housing shouldn't affect the spline wear significantly since there is a flex plate that would eliminate transverse moment loads on the clutch hub/spline shaft interface. IOW the clutch (housing) would have to be enormously bent to affect spline life. The flex plate does not eliminate radial loads however - and that's the problem with bell housing machining errors.

Measuring for angular errors would be done by sweeping the face of the engine rear with a mag based dial indicator mounted on the clutch housing/pack. Assuming the transmission is removed for access, an ordinary indicator setup can be used. A straight edge or square tool bit is probably necessary since the engine's rear face is not a constant radius or is dis-continuous.

Measuring the bell housing for errors is done the same way by sweeping the bell housing face with a shaft mounted dial indicator. Some kludging would probably be necessary to verify the whole surface.

Now - can someone tell me how to measure the error on my R90/6?

 

[happy wanderer]

I think you are visualizing it correctly but from the wrong viewpoint. I don't know the exact dimensions so will simply make up my own to make the point. The OEM configuration only allows the clutch hub to slide partway onto the transmission input shaft. Say only 75% of the way. Now install a spacer which spaces the hub forther rearward from the faces of the clutch disk. So that it engages 100% instead of 75% of the input shaft. You have just increased the spline area of contact by a third - spreading the load and wear over a larger area. What I have just described assumes a new hub and new shaft. If stuff is already worn you are probably just shifting the load to the unworn part that will wear rather quickly until it matches the already worn part.

Paul one of your great talents is visualizing and describing things. What you have said here, especially the part about the amount of engagement on new vs. very worn splines is exactly what I was attempting to describe. I completely agree that installing a new clutch disc with hub extender on a worn spline such as this one is will only cause the unworn rearmost 6mm part to wear out quickly until it is even with the already worn section.

Back in post 18 I suggested the OP replace the spline now because I believe he will be fixing it later anyway for that reason. I think the clutch hub extension for the 1150 is a great idea.

 

[dagear]

Guinea Pig

I guess I will be the experiment. I tend to agree CELE001, that the front of the shaft is lightly worn and the rear is virgin

I plan to put some miles on the bike this year, and next winter I will pull the transmission and provide an update.