CRF 80 - piston ring end gap

Can anyone verify the end gap on the piston rings for a 2004 CRF80?

My manual shows "1998-1999" XR 80, then shows "2000 and later" XR/CRF 100 so I want to be sure before I put it back together.

For the 1998-1999 XR 80 it shows:

Top and second ring is 0.006 to 0.018

Oil rings are 0.012 to 0.035

For the 2000 and later XR/CRF100 it shows:

Top and second ring is 0.002 to 0.008

Oil rings are 0.008 to 0.027

Which measurements should I go with?

Also, do you soak the rings in oil or anything before installation?


Where are all the Honda techs/service folks at?

Rule of thumb.....

Piston diameter in MM................................Min. ring end gap

44 to 50____________________________.004inch

50.25 to 68__________________________.007inch

68.10 to 79.35_______________________.010inch

79.35 to 102_________________________.013inch

Also rule of thumb, but...

Minimum gap

Top ring 0.007"

2nd ring 0.009"

Yes, oil your rings prior to installation; soaking them has no effect that I'm aware of (I've been wrong MANY times before). Also ensure a good coating of oil on all 'contact parts' of the piston; wrist pin, oil lands and ports etc. Take care to ensure none of your ring gaps overlap or are centered over the piston pin area.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now