Some more fuel to the fire. After breaking out the caliper and dial indicators, and a long conversation with Boxermania, Obaid and I took some measurements on his bike's clutch. The first measurement we took was the concentricity. The dial indicator was hard mounted to the engine and we took the measurement off the center hub of the clutch. Total run-out was a mere .005" Far less than I expected seeing how worn the clutch actually was. We did several revolutions of the motor just to check and, while the clutch was obviously off center, it was to the bottom side, as I expected due to wear and gravity... We also took measurements on the face of the clutch disk and it's total run-out was also about .005" Again nothing I would consider excessive. I took a measurement at the edge of the flywheel next to the teeth which returned a reading of .015" I know some of this was due to the part numbers so This was a difficult reading to achieve. Wear on the teeth of the flywheel seemed even and consistent around the entire perimeter. We also, using a magnetic base, took a reading from the flywheel to the engine case/transmission mounting surface. In the areas I could indicate off of, the total run-out was an almost unnoticeable .001" The last measurement was off the nose of the input shaft on the transmission. Again .001" maybe. There was no way to accurately measure the 'out of round' of the input shaft since it is splined.
The findings yesterday, point in my mind to lack of quality materials, not machining discrepancies or misalignment. There was also a notable lack of spline lube on the bike when we first disassembled it. Looking at and comparing the parts that Boxermania sent me from a previous 1150 clutch spline failure, I noticed two things.
First: the clutch wear is identical (pattern, shape, length) for both bikes. This tells us that while it is a failure the conditions causing this are the same. This helps to eliminate riding style, climate, helmet color
and many other variables.
Second: the clutch spline length on the flywheel and shaft are the same.. ~24mm (.945") in length The problem is that the clutch disk sits roughly 7mm (.275") further forward. This leaves only 15mm-17mm of spline actually engaged.
While I don't have readings yet on hardness of the two parts, I should by next week. I've got a shop that has agreed to help with those readings and that along will shed much more light on the subject.
With the recent revelations I am starting to believe that a much more economical solution would be an improved clutch disk rather than an upgraded shaft. I've started discussions with a manufacturer to see if they can produce a clutch disk for the bikes that allows more engagement to the transmission. Also a center section that is hardened more to prevent some wear. I'll make sure and post back when I get any updates.