Hello
Originally Posted by
Fran Ferrante
Be glad to give any info you and your friends need. I was in your spot a long while back.
If you received my private message you can post it.
If not I will post a new one.
Fran
YS Repair From Fran FerranteHi
I have been rebuilding my YS engines for over 10 years.
I can tell you from my experience when you lose RPM the first place to go is the Piston Ring & Sleeve.
If you take the ring out of the piston and put it back in the sleeve measure the gap. if it is bigger than 15,000 that is part of your problem.
Also hold the sleeve up to the light and see if there are any deep scores in it. Also notice if the coating is worn off the inside of the sleeve.
I normally change both Ring and sleeve with the run time you have on it.
Also when you put a new head on the engine you should lap the head to the sleeve with some light compound.
The rear Bearing is a big problem. when you have the engine apart put your finger in the rear bearing and move the inner race see if it is rough.
Check the rotor it should have a little drag on it. If it is loose or really free this could cause a drop in RPM.
I can go on and on.
Any questions feel free to contact me.
Fran Ferrante
[email protected]