Took my bike to the dyno guy and he did a preasure test on my cylinders to check compression came back real low, ? I was wondering if anyone else has done this and what was your results, I guess I have about the same cylinder preasure as a stocker,

 

How big is your cam? Big cams can show lower static compression ratios than smaller ones due to the valve timing.

It might not be an issue...or it might.

You should do a leakdown test as well to make sure everything is mechanically ok.

 

my cams are t-mann 600 lift, and the leak down test showed fine, I was wondering if a big overlap would cause low cylinder preasure

 

What do you mean by "low"?

 

140 psi my cam and head guy said it should be a minimunof 170

 

Personally I don't think 140 is terrible, but I'm just my own mechanic. Was the engine warmed up completely? That could cause a low reading.

 

If you mean he did cranking compression results can be affected by many things.1 th power of bettery slow revolutions lower reading.Big cam w/lots duration same thing.where the plugs both out was bike in neutral or clutch pulled usualy turns faster in neutral.
Most important are cylinders the same or close if they are probaly just bad readings.Also is valve in his gauge working properly Ive had this problem spent half dsy redegreeing cam because the readis where off and had certain are re ran the cams at and checked this way.

 

I am running Woods .650 lift cams, 10.5:1 and compression is good. These cams only have a .244 duration. If you are runing a long duration cam with a lot of overlap, that may be the issue as usually the longer the duration, the higher the static compression needs to be to compensate to gain max power and flow rates.

 

The longer cam duration will cause lower cranking pressure 140 is not bad .. How does it run ? Mark..

 

my cam spec's areopen close Lift duration overlap
intake2139 600 240 40
exhaust 43 19- 242
I wish I understood all I know, my builder things the problem is the screaming eagle cyllinders and pistons