I am doing the valves and piston on my 06 crf250 and just wanted to get other opinions on OEM valves or the kibblewhite valves and other aftermarket valves. what is the differnce,and which should i use? i was also wondering the same about the piston and rings? which do you guys recomend and what has worked best for others.

My opinion, use OEM piston, rings, gaskets and seals. For the valves I would use atftermarket steel valves.

Depends on how many hours you got from the OEM stuff and at what level you ride....

Personally I'd stick with all OEM stuff since with proper airbox maintenance I've gotten 150 hours out of my 2005 OEM head... (although I'm old and slow).

Some thing to consider would be a oem valve with a secoundary coating on the face im considering producing them .the oem valve is a good valve the harder coating applyed over the base coating would make the valve very reliable

redrooster65, on 14 June 2012 - 10:14 AM, said:

I agree with this

I like a couple of aftermarket pistons. I've seen and used CP and Vertex, and believe both are better than OEM

If your bike were a 10 or newer I would recommend OEM valves and most engine builders I've talked with seem to agree.
Since yours is a 06 I assume its no longer a cutting edge race bike, in which case I would recommend aftermarket SS.

OEM gaskets are the best by far. For valves, oem will last the longest for you and are relatively inexpensive. Once you move to titanium valves they are lighter but dont last as long so unless youre willing to dish out the extra coin and go all out they really are the best you can get. FYI most motor mod shops use OEM valves!

Ron Hamp, on 14 June 2012 - 04:52 PM, said:

I have tested this myself.. I had some OEM valves coated with chromium nitride CrN. Running on copper seats, they did 100hrs and never once shifted clearances... perfectly reliable..

The difficulty, is stripping the crappy OEM coating back to bare titanium.. Trying to chemically remove it, leaves the chances of pitting the surface.. some were useable, so not so.. I had to polish the stems with diamond polishing paste..

heres a pic

OEM piston and rings, OEM exhaust valves, aftermarket intake valves. Once the coating goes away on OEM intake valves your done.

kornreceiver28, on 17 June 2012 - 10:54 PM, said:

OEM valves (intake) are titanium. Generally aftermarket valves are stainless steel - which last longer but are heavier which require stiffer valve springs.