Originally Posted by qwerty
yes i know what compression and pinch is. and like i said it has less compression than my JP that has gone over 10 litres. My JP has no pinch.
the sts has gone about 2 litres now, i notice it still has pinch (i.e take off glow plug and rotate, it make small clicks over tdc) , but has very little compression....
i used to have a compression guague but lost it, and i dont think it would even put out 50psi.
i ran it with stock shims 0.4mm and 22.5%nitro using the RB/Rody team method (know as the cyril method on this forum)
theres no fuel leaking between the head button and the crankcase is there? which would indicate a poor head button seal, I would have the head off and inspect for any scoring of the sleeve and piston, usually when you have pinch but poor compression it is due to a damaged piston and sleeve.
I'm just not sure what you consider barely existent to be, it really shouldn't idle well at all and you have manged to put an extra 1 and a half litres though it from the point you noticed the drop in compression by the sounds of it, so I can only assume it runs fine to.