Crompression measure in PSI [Archive]

View Full Version : Crompression measure in PSI

emiliano22

01-08-2002, 08:26 PM

Does someboy know how many PSI have an stock 400ex?
I measure mine and give me 142 PSI, is it too low?

Ketch

01-08-2002, 11:48 PM

This what the Honda service manual says 100-128 psi

emiliano22

01-09-2002, 03:18 PM

is that the normal pressure? or the lower?

Glamis400ex

01-09-2002, 05:14 PM

anywhere between 100 and 128 psi is normal compression. What LOWER are you speaking of?

Glamis

emiliano22

01-09-2002, 06:01 PM

In somewhere say the lower presure you can have, I think it was about 110 PSI. If it is lower you have to move to the next bore size.

papaw

01-09-2002, 06:23 PM

that doesn't really mean you have to go to the next bore size it is merely a guideline to go by if you are low it could be valve seats,head gasket,rings and etc.you have good static comp.without having any major mods.you might have a little carbon build up on your piston but that is usually more of a deal on two strokes because of the oil mixed in.