Originally Posted by
savannahmick
I really like the way this motor is turning out after 1 gallon it holds tune and runs 10 min on one tank also idles forever but I can't seem to smooth idle out all the way has a little pulse. Like I said I can deal with that I think it needs sealing around carb neck and pinch bolt. Anyway I am trying to figure out when is the right time to pull shim like it says in manual or just keep on running it? I don't understand why this motor didn't sell better it runs as good or better than any of the Werks standard B5/B6 motors and lasts longer for sure I got mine for $200 with coupon great deal! When are other owners removing the small shim from head on their R21? Thanks AGAIN!
If its the new version,I wouldn't remove the shim.It already comes with the correct shims installed.The first versions had 1 too many shims.I can't figure out why people don't run this engine I too have had good luck with it and pit at 10 min easily.