Hey i was just wondering if anyone had done a rebuild on a 2010 or 11-12 for that matter with aftermarket gear. What valves and piston.. standard comp/Hi comp and any feedback you have on it. I have rebuild my 2010 twice now all with genuine parts... First motor i got 60 hrs... second im on 34 hrs and im down the the smallest shim on one of my intake valves. I use Motual 7100 full syn and change it every 2 rides without fail. I have 3 air filters... twin air and no toil and i use the bio no toil and change it after every ride. I know im taking all the steps to keeping my motor maintained as i check my valves every 5 - 10 hrs. I can only narrow it down to being on the limiter to much which on a 250 i cannot stop. One more rebuild before i move up to a 450. I am thinking about putting a forged hi comp piston in along with some high quality titianium valves. Just wondering if anyone had any input on the situation.

Branso_10, on 28 May 2012 - 09:56 PM, said:

im actually kind of surprised you have already eaten the valves, the newer RMZ's are known for having a good valvetrain. whatever you do, make sure you get the valve seats cut for the new valves or they will rapidly deteriorate again. i personally have kept to OEM spec parts and the bikes seem to hold up the best with them. are you after more power?

Thats why i am surprised aswell. I had the valve seats cut on my last rebuild and had oem valves put back in it. I keep going back to the fact im running top notch oil every 2 rides and keeping my airfilter clean. I always use premium high octane fuel.. Ive been told by a few dealers that the oem valves are only titianiun coated and once that coating wears the valve will stretch/not seat properly. Im not really aiming for big power gains with using a hi comp piston. I more or less want high quality titianium valves because i believe they will last longer than oem. And for the hi comp piston im not going for big power gains but more grunt in the low to mid range... Which will keep me off the limiter a bit less.

Thats why i am surprised aswell. I had the valve seats cut on my last rebuild and had oem valves put back in it. I keep going back to the fact im running top notch oil every 2 rides and keeping my airfilter clean. I always use premium high octane fuel.. Ive been told by a few dealers that the oem valves are only titianiun coated and once that coating wears the valve will stretch/not seat properly. Im not really aiming for big power gains with using a hi comp piston. I more or less want high quality titianium valves because i believe they will last longer than oem. And for the hi comp piston im not going for big power gains but more grunt in the low to mid range... Which will keep me off the limiter a bit less.

Ti valves are hard on their surface, once they wear through the surface the material underneath is softer so it wears more rapidly. back in my Honda days, stainless valves were the cure for the problematic Ti intake valves. Stainless valves have a nearly homogenous hardness throughout their volume (they wear consistently as opposed to rapidly). some have complained of a loss in power with these replacements but i didn't feel any power loss with mine. kibble-white makes a very good steel replacement valve kit. but im still not convinced the RMZ's oem valves would deteriorate that quickly, check the valve guides, your air boot to box seal, and are you positive they cut your seats (just wondering since you only got half the life out of the replacements) which coupler have you been using?