When I am ccing the trapped cylinder volume @ TDC, before I torque the head down, I'll smear a bit of grease on the edge of the piston to seal off the rings so none of the oil will go down beside the piston. Then once the head is on, I use a plug hole dial indicator & find correct TDC & then lock the crank down in that spot so it cant rotate & get off TDC.
Your only getting the trapped cylinder volume when your ccing like that & not a true head dome volume.
Head dome volume cc, is as detailed earlier with using a flat plate over the gasket surface of the head, sealed good with the spark plug in place & then inject the oil in & note the total cc amount.
Just by reading what your saying so far, that you've already ran that engine a few times & it was not a monster to kick over to start up, I would say the compression shouldnt be to high, nothing over normal that would kill the engine if left as is.
Now if it was a bugger to kick over to start up, hurt your foot with boots on, then I would say you better be ready to hang on when riding & be on your toes jetting that carb before you put a foot on that kicker, (every time) & use good quality race gas so you wont melt another piston down.
This is to any & every 250R owner.
It makes no difference who built a 2 stroke engine, being the highest quality it could be built, be it Allen @ CT Racing, Arlan @ LED or even BDT building it, that engine will run no better or last no longer, than how much that person knows that is tuning on that carb feeding it gas mix.
That carb is feeding it what keeps it alive, so when you skimp on that, your making its life shorter.
A 2 stroke is simple in design & simple to make it have a long life, so we shouldnt try to over comp things when dealing with them.
Compression ratios are like dyno readings, thats all they are to either list or brag about & when its all said & done, either your foot or your butt will give you the true reading of what that engine is doing before & after it is running.
Neil
