compression PSI

[baker250r]

running a 310 esr and after i pulled the compression test on a pump gas dome I got 160 PSI with a warm angine and WOT. is that a little low, or is that normal compression with a pump dome? I guess I always ran race gas domes and was always in the 220 range, I have never dealt with a straight pump dome. I think it is low but i dont want to re ring it if im wrong. thanks in advance for the help

[deathman53]

if you did it right, its really low. Did you test the compression w/ the throttle WOT?

[baker250r]

Yep. Its also a pv motor. not sure if that affects compression at all. I just rebuilt the engine and ran one race yesterday and just didn't seem to have very firm kicks at the end of the day. Had a clean filter and klotz oil at 40:1. Only ran 2 motos. Everything is air tight and the motor was actually running rich according to the plug. I also replaced crank, bearings and seals in the rebuild

[JackBrown1988]

Been told 160 is 2 low. my wifes oem motor on pump gas kicks 180 psi. same piston for past 7 years. always kicked 180/185 psi

[number5]

I have had different readings on 4 different gauges. Ended up borrowing a calibrated ashcroft gauge. Three of the compression testers were more than 8psi low. The other one was high. So do you trust your gauge?

[Honda 250r 001]

Ive always checked my compression with a cold motor. Id try that and see what your reading is.

[zedicus00]

160lbs psi is what esr considers pump gas compression.

when you get a dome from them tell them the cc you want, not the fuel type. they err on the safe side.

actually you need to know the cc of your dome before we can tell you if 160lbs is low.