what happens if this is to high or how can you tell from pulling it over should there be some resistance when the piston is coming down from tdc to when the transfer ports open?

 

Ok I don't know if this will help but I have put a vacumne\pressure gauge on my 250 and at cranking speed (this gauge records the min max pressures) I get a max of 4 psi before the transfer ports open. I can't say that I can feel the resistance of the 4 psi when pulling it over but I can just feel it turning the clutch by hand with the plug out I hope this is what your asking.

Jeff
2003 trailblazer 250
RcR stage 1 milled head
10-42 gearing
150 main
58g weights polaris pink pri. hpd plain secondary 2-2.

 

Jeff where are you putting the gauge some where on the crankcase it's self or in the spark plug hole?

 

Tweeker, buy a degree wheel and get the head off of that thing and degree it. The numbers will not lie to you. For all general purposes, keep blowdown around 32-34 degrees. A good degree wheel doesnt cost that much ($20), and it will tell you how to find top dead center and you can check everything in about 10min with the head off. Too much blowdown without enough transfer timing will be very doggy on the bottom end.

 

ok bubba I will do that lets say for instance there is to much then how do you cure the problem I have done some other things to the cylinder and if it doesn't work it's junk and have to find a new one.

 

well, the biggest thing you want to know right now is how much exhaust timing (duration) it has. With a race pipe you can go 202 to 204 degrees duration but that would be max. The other thing is that the transfer timing needs to be higher (raising the ports). The amount of degrees from when the exhaust opens to when the transfer ports open is the blowdown amount.

 

I'm putting the gauge in the crankcase drain. But I don't think you can tell anything from pressure too many things could affect that. Like Bubba said degree it.

Jeff