CRF intake valve question

W

wkbrdbm

Member
Feb 11, 2007
2
0
After trouble shooting why my 450R wouldn't start, I found that the intake valves needed to be replaced. I lapped the exhaust valves while it was apart and lapped the new intake valves as well. After putting it all back together, I read in the manual that the intake valves are NOT supposed to be lapped because they are titanium and there is a special coating to protect them. Lapping the valves removes this coating.

So my question is, is this a problem and is there something I should keep an eye out for? Or, don't sweat it and just ride it?

Thanks for any input.
 

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
6,958
45
It depends on how heavily you lapped the valves. I normally do a very light lap to insure a proper seat but, if you lap them too much you will wear the coating off and they will become soft. Then the valves will sink into the seats very quickly. If you have much time on the valves they should all be replaced since the ti valves can fatigue and break.

Using the stainless steel valves and spring kit will eliminate this. The stainless valves can be lapped and reused. Kibblewhite valve and spring kit is a good way to go IMO.
 
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