I've purchased a couple 4g kits from bicycle-engines.com and they were the tapered shaft engines. The clutches that came with these kits had an engagement rpm that worked fine. The last 4g kit they shipped me had the engine with the 5/8 shaft. The clutch in this kit wants to engage when I pull the recoil starter. I installed stiffer springs in the clutch because I had success doing this with these clutches in the past. Didn't work this time. I installed some shims with the stiffer springs and now I can start the engine without the clutch engaging, but it tries to engage at idle. I set the idle as low as it will go without stalling the engine and the clutch is on the border of engaging. Anyone else buy the 4g from bicycle-engines.com with the 5/8 shaft engine? I have one more 4g kit with the tapered shaft engine and I was thinking about putting it in this bike just so I can have a clutch that works properly.