starter clutch GS1000

[Anonymous]

I have recently replaced the three rollers in the starter clutch which had developed flats on them, causing the starter not to grip and failing to start the engine. It appears that the new ones are now failing in the same way. Anyone had similar problems? The engine is bored to 1085, new valves. Anyone got an answer to prevent reoccurring.

[massakins]

Premature starter clutch failure can be caused by a couple of things.

One of them is flat spots on the three rollers and/or the mating surface on the clutch gear. They seem to develop simultaneously. Replacing only the rollers is cheap but typically a very short lived solution. Inspect all mating surfaces for flat spots and replace both at the same time. It doesn't take much for these to fail.

Secondly, be sure the three bolts on the starter clutch are tight and ensure that there is no loosenes between the starter clutch "holder" and the flywheel. Tight bolts don't guarantee no looseness here. Always loc-tite these bolts. Also, looseness here can cause this gear to move off center and bind with the intermediate gear; this can slow down the starter motor or even keep it from turning over.

Third, make sure the rotor fits tight on the crank. This is more than just torquing the bolt. I've had good luck using lapping compound to improve the contact on troublesome fits here. Loc-tite seems to help here too.

Your 1085cc kit shouldn't be a problem. However, if it was high compression with big cams, strong valve springs, etc. then it may be taxing on the motor. These bikes don't seem to have the overkill in the starting system that the new bikes do.

If the rollers and their mating surface are smooth and move freely, if the bolts and the "holder" are tight with no looseness and if the oil isn't embarassingly contaminated and old then you should be fine. Failing this can cause the clutch to not disengage once the motor is running, then overspeed and catastrophically fail, i.e. pieces everywhere. I saw this once and it was ugly. Also, a well tuned engine that doesn't have to be excessively cranked to start is a real relief here.

[Anonymous]

starter clutch GS1000

Massakins.
Thanks for the advice. obvious, but I was too slow to realise! I know all bolts were secure on reassembly; so checked the spare starter clutch unit on a 100k mile engine. It had a series of flats all around the ring, so the one in use may well be similar. Whole new starter clutch assembly is ?130 delivered in UK, now ordered. Will have three months to fit it, as the weather here at the moment messes up the alloy show rims.

[Anonymous]

starter clutch repair!

Holiday boredom drove me to the workshop & I pulled the starter clutch apart to find the problem.
The three rollers were chewed up, the bearing surface appeared to have gone through an acid bath. The idler gear bearing surface was reasonably good, no significant pits or edges. The problem was found in the 'cheeks' of the cage for the three rollers (behind the alternator rotor). Having removed the three cap head screws, the assembly fell apart. The cage and a flat steel plate form the operating channel for the rollers - they are pushed forward by their respective spring and pins. The rollers had snagged at an angle into the cheeks and become stuck, creating gouges in the cheeks.
It shows, once again, that merely renewing the damaged rollers is not enough, the whole assembly must be considered.