Wednesday, August 10, 2011
Lessons learned from complete clutch rebuild
Not surprisingly, I learned that Tom G. was correct about why the needle bearings were binding. This evening I disassembled the clutch 100% (yet again) and with a few taps all of the oiled needle bearings fell out. Furthermore, they all we reinstalled very easily around the circumference of the race. There was no binding.
A couple things to note:
(1) The entire clutch was rebuilt when the engine was done. VSX parts were used with the exception of new needle bearings. I did not receive the original ones back from Christopher M. after the rebuild so I can not compare the sizes, but I do know I just bought 40 new ones from Scooters O and Gene M. successfully installed them in another SS180 that had a similar problem and now there is no grinding noise from the clutch.
(2) A trick for tightening the brass ring I learned from Tom G. is "Put backing plate down on wooden surface. Screw two sheetrock or other screws in place adjacent to the "ears of the backing plate. The screws keep the backing plate from turning. then you use the tool to unscrew the ring. Use just enough force to get the ring to turn. " I took another approach and used three small headless nails and lined them through both plates and turned the top plate so each locked against the nail and there was no movement. I then tightened the brass ring and could lift the clutch assembly off the wood base. Tom's idea may be smarter as it could be less stress on the two plates. I hadn't reread Tom's note and could not get my Sheetrock screws to fit the holes the nails did.
(3) For the brass ring there is no torque guide and it is unlikely to loosen since it is a reverse thread. I kept my hand directly above the socket (less torque) and tightened it down with one jab. Then I stopped. Brass is not that hard.
(4) What I did notice is that the NOS clutch springs (I point to the NOS ones in the slide show) I just purchased are noticeably taller than the VSX ones. Furthermore, they sit in the cups much more snugly. I wonder what difference, if any, that could cause. I did not receive the original ones back so I could not compare the difference in height or width.
The only question now is if the scoring wear on the bottom of the brass ring nut is acceptable or if it suggest that the needle bearings will eventually wear through enough for the brass ring to fail or to cause binding of the heads of the bearings at low RPMs -- hence the sound between neutral and first gear. I want to know this answer ASAP. Follow-up: spoke with Tom and he said that the ring has wear, but not truly scoring. He said their is nothing wrong with the brass ring as-is.
So . . .
At this point, I guess it makes sense to reassemble the bike and test it. If it works, wonderful! If it doesn't it's not hard to replace the clutch and I will need to buy a new one.