Starter Clutch Upgrade

[bobtail84]

I was at Brands Hatch racing circuit here in the UK on a track day and while I was attempting to reach terminal velocity I missed a gear when shifting between 4th and 5th on the start finish straight. The engine, unsurprisingly, over revved and not knowing what damage I had done made my way back to the pits. Once back in the garage there was a noticeable rattle at idle that disappeared when the clutch was slowly let out, this was a familiar sound that indicates the starter clutch was damaged. When the stator cover was removed the problem was revealed.



2 of the 3 bolts had broken that hold the starter clutch to the flywheel and to be fair it could have been a lot worse. This is not the 1st time I have damaged and replaced the 3 bolts and I know it is one of the foibles with our bikes.

I was having a mooch around the interwebs when I stumbled across a post by Centurion Motorcycle Projects who has designed a solution to the starter clutch problem. I contacted the owner, Brian, and arranged to send my starter ring and flywheel up to him for modification. Just for clarity I have no association or any kind of vested interest in the company, I just wanted a solution.

This is taken from his eBay listing "Suzuki GS series uprated and modified starter clutch bearing assembly arrangement. I've been working on this upgrade for many months, exclusive and only available from Centurion Motorcycle Projects. This new modified bearing assembly will eliminate for good the dreaded issues found with the OEM 3 barrel roller type bearing. Our process involves turning down this ring gear as there is always wear to a tolerance suitable for our custom sized bearing. The bearing has been designed and manufactured by us for the mounting of the new 20 point contact one way bearing, this is where the major improvement is over the old 3 point contact design. Our bearing is a weld on type eliminating the old 3 bolt fixing that were prone for becoming loose".

I sent my starter ring and flywheel up to him and received the below back the following week.





I also purchased a pair of new OEM bearing's for the ring gear just to be sure,



I re-assembled the whole lot and forgot to take more photos it's all back together and is working fine so will update with any comments or problems but I don't envisage there being any. While I was waiting for the parts to be sent back I did check all the shim gaps just in case there was any problems after the over rev incident, thankfully there were none and I fitted a rev limiter while I was rummaging around.





I will keep an eye on the starter clutch upgrade and update accordingly.

[chuck hahn]

Typically heat and magnets dont play well together. So im wondering with the extreme heat of welding on a rotor does it impact the magnetism and does it harm the adhesion of the magnets to the rotor? Whats it charging at after the retrofit?
The overriding problems with stock setup are the weakness of the bolts so i upgrade to grade 8 bolts. Second is the cheap springs. They are spindly and break a lot. My fix is to buy a 3 pack of click style ink pens and use those springs. More robust and they do the same job just fine. And i use copious amounts of red loctite after thoroughly cleaning the threads with Qtips and carb spray to degrease for max loctite adhesion.

[Nessism]

The overriding problems with stock setup are the weakness of the bolts so i upgrade to grade 8 bolts. Second is the cheap springs. They are spindly and break a lot. My fix is to buy a 3 pack of click style ink pens and use those springs. More robust and they do the same job just fine. And i use copious amounts of red loctite after thoroughly cleaning the threads with Qtips and carb spray to degrease for max loctite adhesion.

Click pen springs? And the OE bolts are already heat treated, at least as strong as SAE grade 8.

[chuck hahn]

Yes ink pen springs. Tougher and they work fine