daveyson wrote:Charlie did you remove the engine from the frame, and do you think some of the following guesses are sound?
I was going to say the rubber dampers harden and shrink because of what I've learnt from your previous posts, but was just getting economical with my words, I think it's both happening. I thought hopefully it's just bad dampers cause the noise goes away when warm, although this problem would put excessive strain on the absorber rivets.
I was thinking the earlier, stronger, annular spring might cause the holes for the retaining tabs to grow too large, but anyway that doesn't apply in Dave's case.
If there's no damage related to the rivets (maybe visible with the crank cover removed) on second thoughts, maybe it's not so non-urgent. So then it would be good to fix before that happens, but I spose some would say, since you're in there anyway, go ahead and replace it with the newer 12 rivet, improved absorber.
I've read a good thread on this topic that Laitch made a link to by Albyalbatross, is that the thread you're referring to?
I was guessing that a loose idle gear and annular spring would still be noisy with the engine at idle, and warm.
yes removed the engine from the frame as i had just striped out the clutch centre ...again ..after procrastinating about lubing the clutch splines for so long ... and many kilometers , again through many rain event travels .
thought it was about time to do Gerty's output shaft in any case whilst this deep into the gearbox - driveline disassembly .
I think that there is more compression when the motor is cold , or maybe just more reaction of acceleration of the crank when cold rather than warm , so is much more noticeable and possibly less oil flung around the output gearset off the crank .
i think that its worthwhile doing now rather than later , as i think that the wear patterns setup by the excessive backlash could advance the compression wear of the barrel rubbers , then stressing out the rivets .
pitty it wasnt an late 88 bike as it would already have the 12 rivet assembly
its funny the rubbers i have seen and that i have replaced dont follow any real service issues ...perhaps ... maybe certain oils affect them ? or is it a production batch issue ? along with worn backlash tensioner issues ?
in any case doing the backlash spring stuff would certainly give the opportunity to replace the inexpensive rubbers before more work needs to be done , besides replacing a 6 rivet with a 12 rivet output shaft second hand (even with low kilometers ) wont guarantee that you wont have to do the same all over again .
yes Alby's investigations were well noticed by me and other who were active in the forum back then .
ill post up some of the things i have found between a lower kilometer 6 rivet pre 85 shaft with good rubbers and no noticeable movement on the gear to damper ...and a 12 rivet shaft that came from our mate "Rene "...(who lives just round the corner these days )
in fact the 12 rivet shaft has noticeable wear on the output bearing .....which is not available anywhere at the moment , unless you can find a dealer that has one on hand ...
hope that helps some .
luckily i have noticed a lot of things , having been inside there more than twice
fortune has been on my side as i have a rebuilt motor with good 6 rivet output shaft and rubbers that i have been reassembling to go into Gerty for the time being ...