I've put on this head on my mx a month ago and (maybe it's just in my head)I think it knoks on idle!Maybe it's because I havent heard the engine 4 a while but!!!!!!!!What do you guys think?The engine as only 1500miles on.How do you guys like the head?Well in about 6 months it's gonna be time againe.Thanks in advance Tommy.
I cant say enough about mine. This thing rocks. You might want to drain the tank and put 92 or 93 octane in and see if that fixes it, sounds like an octane ping maybe. cross your fingers nothing came loose inside. I have had many combos with this head and havent had any problems so far.
Doubt if its ping at idle, probably piston slap, let it idle and than turn it off listen to see if the knock continues until motor stops dead. Piston slap if excessive will result in a hooked ring or piston skirt failure.
Bonzi, you are absolutely correct about the noise at idle not being octane related, but that is an easy place to start and maybe blk800 might get lucky and not have to tear it down. Also blk800 you might want to have your timming checked at the dealer, this would be the second place i would look, if the gas change and the timming check doesnt fix the problem you will have no choice but to open it up. Just my 2 sense. good luck and let us know what happens.
You have nothing to worry about. *The head does make a little more noise than the stock head at idle. *There are reasons for this. *The biggest culprit is the lack of support on the piston with only one ring. *We go through this with most every 800. *You should here the racket it makes when you replace just the rings. *You would swear the rod is coming through the case. *The reason for that is the new rings don't seat on the old piston. *After about 300 miles all is good. *Gotta love these new series III engines, they are famous for piston slap IE (knocking in the engine).
Hey blk 800, did you measure the squish band when all assembled,like with a piece of solder wire. probably is the bad gas from 3 moths ago,espesially if it's low test gas.
