Exhaust Valve's

[calum17]

Hi. I have just put my bike, ZZR 600 E11, in for a service at 8,100 miles. As far as i know eveyrthing is fine so far, well - they took it monday to do tuesday (so it was cold and so on - start early) except they phoned me this afternoon to say they started late and it wont be done today...not pleased - but cant change that.

anyway, all 8 of my inlet valves are ok and within the Kawasaki tolerances. but 7 out of 8 of my exhaust valves are out of spec. one was quite a lot out too. i told them to just sort it as the bike was in bits for the service and as i dont have it i can keep not having it for now. and i can sort the money just about ( i hope. lol )

what i wanted to know though, what causes the exhaust valves to get so out of spec so soon, or cn it be normal? i understand wear and tear does it but it just seems rather soon into the engines life. would high revving or back fires cause it (im guessing yes to the back fires .... but dont do them loads and wont do them often from now on anyway) so just wondering, so i can go see them with a bit more information and knowledge behind me.

thanks
calum.