2002 yz125 compression

[tyler_43]

hey, I was wondering if anybody out there knew the how many PSI my top-end should have... I've got quite a few hours on it and my shop has (for some weird reason) had a tough time getting me a manual.
-thanks

 

[whenfoxforks-ruled]

Try service honda for a manual. I would be guessing somewhere over 160 psi. This can be deceiving on ring and piston wear. Normally for a compression tool to be effective you should have a fresh top end, then record your reading and check every so often. When you see a drop, then you know its time. A leak down test is effective for checking your bottom end seals.

 

[KTA]

A cold 125 motor in good heath should be showing at least 160psi. It'll run with considerably lower pressure, but you risk causing damage. An optimal motor will have over 180psi.

 

[zaneyzrex]

150psi or more if in good shape
100psi and if its done

 

[CRazy250]

yeah i had to order a manual from yamaha for my 02 yz125, it cost like 50 bucks.