Z400 valves

[fmftrx300ex]

i have an 03 z400 and its got quite a few hours on it and iv heard the stock valve train is alittle on the weak side would it be worth it to pull the head do valves a cam chains and rings or did i just hear wrong

[JBENSON]

I have not heard of the valve train being weak, but I have seen the timing chains stretch after many hours, they will become noisy. Put a new chain in it and check the valve clearance and then you should be good.

[Colby@C&DRacing]

If you aren't hearing any noise from the cam chain or if your valve clearance is good and they haven't needed any frequent adjustment then they are probably wearing normal. With that being said we have had to do a lot of topend maintence on the z400's.

[fmftrx300ex]

i was just curious if itd make sence to replace the valve if i had the head off

[Colby@C&DRacing]

If you have the head off I would replace the vavles and piston

[chronicsmoke]

Yah I've got an 04 thats hard to start sometimes.. I have to bum start it. But then it runs great..

I did some research a while back to find that the stock valves have a tendency to "cup" (cupped valves)

Not 100% on the technical terms but I know Im going to change the valves and cams in the spring. Ive got to wait till I'm finished my winter rebuilds on the 450r and 400ex. Or if i win the lottery I'll do it before :rolleyes:

[fmftrx300ex]

yea it sounds like ur valves may have "cupped" or worn enough to gize u like no valve clearance that causes the hard starts where it will just crank and only bumb cause its turning over faster longer check your valve lash its listed in the manual and yea my clearences still check out so my valves are prolly fine my dad rides it like its a harley so its not often reved out to hard:rolleyes: