Should I be worried?

[vr4king]

Well after a recent top end i went to check the valve clearances and noticed this scuffing on the bearing cap and on the bearing not 100% sure if it was like this before the top end or not any advice?

[unstuck]

Surely that would of been noticed during rebuild. Looks like it never got cleaned out properly, scoring on the cam does not look too bad in the pic.

[flyingcr250]

New bearing! For the love of god new bearing.....

[vr4king]

New bearing it is then I know these are machined as a whole unit so hope its not rooted otherwise its a new head grrrrrrr i have just poured about 500 into this one

[ktm84mxc]

Take it to a reputed Engine builder and get it checked be very through it may be salvageable but only a expert can tell you.
A few you just put it together and sell it letting the next owner carry the cost, not nice but does happen.

[Dave89]

It looks like the bearing has spun in the head and cap, was the cap done up properly?
The roller bearing should not spin in the cap, perhaps fit a new bearing and use a small amount of loctite bearing retainer to compensate for cap damage.

[vr4king]

Thanks guys as it happens i work with 2 very good engine builders,they told me to put it back in without the cam chain on it and torque it up to spec and see if it spins freely if so no need to worry

They also gently cleaned up the caps with some 1200 wet and dry very very gently

So hopefully its all good

[Jinxycat]

New bearing! For the love of god new bearing.....


:innocent:

[Dave89]

The cam will spin freely if you put it back together, there will be nothing wrong with the inner of the bearing. The damage you are showing is betwen the outside of the roller bearing and the cap. these do not spin against each other. They are supposed to be stationary,The cap is to hold the bearing in place,
you need to know why the bearing outer race has spun in the cap/head to cause that damage.

[CRF119]

To me it looks like it has spun. Unsure if it was that bearing or the previous owner may have had a bearing lock up and spin and just replaced the bearing. Or the previous owner forgot to tighten the bolts and then it spun. Its hard work to make that bearing spin in there!!! A friend of mine ran his CRF250 with no oil by mistake. He ran it for over 30 min before the power had reduced. The top bearing had still not spun like that but that cam was blue!

So my guess is once upon a time it wasn't talked up right and spun.


If the bearing feels good assemble with a small amount of green loctite. If your worried then replace the bearing.

[vr4king]

Yeah the local crf guru tells me its normal to sometimes see some very light scuffing there.

In she goes............stay tuned for a very cheap crf :facepalm:

[Dave89]

To me it looks like it has spun. Unsure if it was that bearing or the previous owner may have had a bearing lock up and spin and just replaced the bearing. Or the previous owner forgot to tighten the bolts and then it spun. Its hard work to make that bearing spin in there!!! A friend of mine ran his CRF250 with no oil by mistake. He ran it for over 30 min before the power had reduced. The top bearing had still not spun like that but that cam was blue!

So my guess is once upon a time it wasn't talked up right and spun.


If the bearing feels good assemble with a small amount of green loctite. If your worried then replace the bearing.

Agreed.....

[Paul in NZ]

If you are worried invest in a little loctite bearing location stuff.