Crf 250 HELP!

[Trelex]

Hello TT, i have a 2005 Crf 250 that was hard to start and jump started fine. It wouldnt idle good either. I decided to check the valves.

I looked at the valves and got these measurements.

INTAKE (LEFT) .005 (which is perfect)

INTAKE (RIGHT) 0

EXHAUST (LEFT) .005

EXHAUST (RIGHT) .005

IN .005 +/-, EX .011+/- <--This Is what there suppose to be at

My shim sizes are the following:

INTAKE (LEFT) 1.81

INTAKE (RIGHT) 1.60

EXHAUST (LEFT) 2.50

EXHAUST (RIGHT) 2.42

How do i find the NEW shim size for my RIGHT INTAKE which is 0.

I tried the formula on the others and worked good. I know i will need new valves very soon but i am going to sell it when i fix it so please don't tell me to buy valves. Thank you in advance.

[Charlie C]

You just have to keep trying different shims until you get some sort of clearance out of the right intake then calculate the difference. There's no telling what it needs until you have some space to work with.

The intakes are suppose to be between .004" and .006".

The exhaust valves are suppose to be between .008" and .011".

Anywhere outside of the specs I gave you can make it next to impossible to kick start.

[Trelex]

Thanks I will start with a 1.48 shim then.

[manderson_712]

You could go ahead and shim it but will most likely only get a couple rides out of it before it dose it again. Your valve with 0 clearance is cupping and wearing into the seat of the head.

To solve your problem you are going to need take your head apart and have all the seats cut and replace with new valves. I would recommend a kibble white valve kit. This is a common problem with these bikes.

[Charlie C]

Do re-seal the air box. There's a bunch of posts that explain it step bu step. That's the leading cause to short valve life. You really shouldn't have to mess with the exhaust valves. When you do eventually replace the intakes, have the shop look at the exhaust guides. They do go bad and it will burn oil and the exhaust valves will not seal properly for optimum performance.