The Cat's Meow For Splines, I wish

Just opened my 2002 1150 at 62k miles for transmission input shaft inspection/lube. Splines perfect fortunately. Looking at the shaft (instead of a picture) for the first time I saw one of the reasons for failure. The shaft is TINY. Read here about an improved clutch disk with a longer hub which is certainly an improvement if the shaft hasn't trashed yet.

But if the shaft is stripped or on it's way I think I've seen $1G for a new shaft plus a transmission tear-down.
Since someone has the capacity to install a longer hub in a clutch disk, then they could just as easily install a BIGGER hub. Larger OD. (Stay with me) Now add a simple machined collar over the damaged shaft, old spline size for the ID, new, bigger splines for the OD. The stripped ones appear to have enough spline left to hold the repair collar, just in the wrong place to engage with the clutch. A snug fit and Stud and bearing Loc-Tite or Caterpiller branded epoxy would easily hold it on. The only force applied longitudinal is generated by the riders lift hand on the clutch lever. Cheap, easy, straight-forward manufacturing, no transmission tear-down.

The spline size is adequate if the splines are kept lubed with the right grease.
My guess is that a bigger spline would last longer but still fail without proper lube.
My 2 cents.

Why dont cars and trucks require spline lubes? Winter boredom question.

PAS said:

Why dont cars and trucks require spline lubes? Winter boredom question.

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Good question, and I'd add, a second, why don't cars and trucks required yearly valve adjustments?

Roger 04 RT said:

Good question, and I'd add, a second, why don't cars and trucks required yearly valve adjustments?

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That's easy....

Hydraulic lifters

MotorradMike said:

The spline size is adequate if the splines are kept lubed with the right grease.
My guess is that a bigger spline would last longer but still fail without proper lube.
My 2 cents.

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The idea was about salvaging an expensive damaged shaft. The larger spline would just be a added bonus. As pointed out by others, cars and trucks don't need a tear-down periodically for a spline lube. Why should these motorcycles?

I would say that there is much more movement of the shaft on the splines due to a short driveshaft, and long suspension travel.

Ken

GKman said:

A snug fit and Stud and bearing Loc-Tite or Caterpiller branded epoxy would easily hold it on. The only force applied longitudinal is generated by the riders lift hand on the clutch lever. Cheap, easy, straight-forward manufacturing, no transmission tear-down.

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Epoxy is strong - but not that strong, especially with at higher temperatures.

Also - the spline system would maybe be be ~25% stronger if there was a full axial engagement, but I don't think engagement is the life issue here. Poor alignment and fretting corrosion is what's wrecking these parts.

I sent my K bike rear drive to Bruno for a rebuild. It came back with a much longer set of splines to lubricate. A few years late, took my K to a dealership for a spline clutch and clutch repair. After paying the bill the service manager said that someone had tampered with my rear drive and tooled it back to specs. Haven't been back there since.

Ken F said:

I would say that there is much more movement of the shaft on the splines due to a short driveshaft, and long suspension travel.

Ken

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Wrong shaft Ken. Talking about the clutch end.

nrpetersen said:

Epoxy is strong - but not that strong, especially with at higher temperatures.

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I calculated at least 1.75 square inches of surface area just on the faces of 17 splines X 3,000 psi epoxy = 5,250 lb. If I subtract 25% for missing/ damaged splines there's still two tons resisting being pulled off (a direction there is very little force applied). Green Loctite is rated for 450F. Do you expect to see that in your clutch housing? I guess John Force might, but I'm not recommending a fix for one of his funny cars.

I like the idea of a replacement collar. It could be sold as a kit: collar, new disc, adhesive, pins,etc. But am I mistaken that the most force on this shaft is not the back and forth drag of the disc, but the rolling force of the disc on the splines. And that is probably considerable. To counter that, couldn't the collar come with either several set screws at different points, or, if the shaft is not hardened, pilot holes in the collar to allow the installer to drill through the shaft and install roll pins to prevent the collar turning on the old splines? The collar could be hardened and would probably outlast the original shaft splines, which, from BMW's point of view, need to be pampered regularly. I notice that in the new R engine, BMW finally gave up on this system and went with a wet disc clutch. Good.

jconway607,
Thanks for your interest and input. The details you mentioned are ideas that need to be explored and tested to make a quality product. I have no interest or need to develop the idea. I entered it into this public domain in hopes that someone would take an interest and develop and market it.