Originally Posted by Killa G
Last year the motor ran great for me. It is this year that I am having slight problems. Trying to narrow down the source. Only changes I made were the conrod and bearings.
One area to look for tuning problems is the low speed needle o-rings. They tend to be split easily by the sleeve. If a problem - fit the new ones with lots of rubber grease or teflon grease. (seal the whole end of the slide if necessary once you get the LSN set)
Also the possibility of air leaks on the back plate etc after the repairs.
New rod can increase compression - what is the shim stack dimension. Did you replace the head shims? They get distorted and hardened after fitting.
These motors are great once you get all the bits in place- but they are not too tolerant if the clutch, gearing or tuning is out of range. They are also thirsty when running strong. But when you get them right they run like a bat out of hell. Well worth the effort.