Compression psi rating for 125's

B

Big Daddy

~SPONSOR~

Dec 10, 2002

32

0

• Dec 10, 2002

• #1

What should be the compression psi range for an 98 CR125.
I have 115psi kicking it hard 10 times with gas open.
I bought the bike used early this year. Is it time for a rebuild?

 

G

Glitch

~SPONSOR~

Dec 3, 2001

630

0

• Dec 10, 2002

• #2

I think a healthy compression for a 125 is around 150-160. So yes, you should rebuild the top end.

 

1

125 rider

Sponsoring Member

Oct 1, 2000

408

1

• Dec 10, 2002

• #3

yea, its definatly time.

 

C

cr25096er

Member

Apr 16, 2002

707

0

• Dec 11, 2002

• #4

i wouldnt even run it at all w/ compression that low. my 91cr125 w/ a fresh top end had 180psi in just a few kicks.

 

M

MikeyG

Mod Ban

Nov 28, 2002

100

0

• Dec 11, 2002

• #5

It should, cr25096er. It can run with 110, but I think the compression tester may be faulty.

 

B

Big Daddy

~SPONSOR~

Dec 10, 2002

32

0

• Dec 13, 2002

• Thread starter
• #6

Update! I tore the topend apart, the cylinder mearsured 2.1251-2.1255. But the piston didn't fair very well. 2.1220 at the skirt and 2.114 right below the ring. :eek:
How much should the piston taper for top to bottom, about .0020?
The bike ran fairly well but lacked top end.
Getting a Pro-X piston set with .012 base gasket kit. (stock is .020)
Sounds like I should be in the 160-185 psi range.

 

A

A-RustyDemon

~SPONSOR~

Dec 9, 2002

152

0

• Dec 13, 2002

• #7

Well according to honda service tech. The 125 CR should have a reading of 135-145. When you get a reading of 118-120 time to replace.