Shim for 4g

In my quest to replace the mighty 'hoot' I decided on going with the 4g and add on the SBP shift kit. It appears that I have the slightly smaller diameter HS straight shaft and the 5/8" 4g will not fit. Has anyone shimmed one of these to fit the 4g with dependable success?

I know the q-matic has a shim fix, but then I would have to modify again to run a shifter. Oh if there was just a multi-speed q-matic in production.

I thought putting an engine in a bike was suppose to be easy bolt and go process and you rode along with rainbows in golden paved bike lanes.

They sell shim stock online and at Graingers of different metals and exact thickness. I can pick up a roll of .2mm thick metal and wrap it to size, but having to cut for key and handle higher rpm's I'm not sure if it will hold true. I was hoping someone else had already mastered the mod and could provide a little insight.

I'm not sure EZM would sell a separate shim or match up to a 4g...I may check regardless. I could also try to marry the EZM and SBP kits, but the mod may be beyond my time frame. I need to have this done in the next 10-14 days or give it up and limit my travels within hoot break down range and just hope it holds.

There does not seem to be a simple step procedure to resolve my need for this motor. Should have done a little more research and bought the correct 4g kit to begin with, but that error is behind me.

Thanks azbill much appreciated. If the shim plan is working that well I'll give it a go. What are you using for shim material?

I found a post from Quenton which said the straight shafts were either 15mm or 15.8mm, so I would say the shim is .8mm. Now I just need to find a pace that sells small lengths so I don't spend $15 on a 30 cent part.

I checked the Grubee site and they list the shaft at 15.87mm. Are you using 4 layers of the .02 or just one and leaving the .67 slack? Also do you run the shim the length of the shaft or just length of the clutch puck?

Mcmaster sells a .008 inch stock which equals .0203 mm so should work fine. Once again, I appreciate the help I know I'm tossing out a few questions.

On the bonus side I'll have about eight feet of shim stock so if anyone else needs a snip for the same issue let me know and I'll mail it your way.

Update: The one shim at the .0203mm size worked great, doubling up was just to tight. I ran the shim the length of the shaft and around the diameter to the edge of the keyway, leaving it open gapped. The four bolts to attach the 4g to the 15mm shaft HS were metric size 6m by 25mm length and also worked for the shaft bolt.