help, carb or valves or what

I ride my '06 450 almost weekly and it recently started running like crap down low, it came on rather suddenly and is somewhat intermittent. It is very hard to start sometimes and when warm it wont idle at all. I replaced the pilot jet and cleaned the carb twice. Checked the valves and the exhaust looks good but 2 of the intake valves are on the tight side of spec but are in spec if Im doing it right. I have never had to adjust the valves but these are the tightest they have measured. My gut says it is carb but I am unsure. The choke has been bent for about a year but opens and closes good. Plug is black and new, should I adjust the valves to loosen then up a bit or try to clean the carb again or what?

Thanks in advance for any advice you can give, thank goodness my nieghbor has a yz125 I can ride because Im jonesing xhard.

I just read krannies reply to another post and will try to clean thecarb more thoughly .....

black plug means its running too rich - is the choke stuck on?

It may be, it has been bent for over a year but seems to close all the way. Im going to get a new one to be sure.

would tight valves cause a lean or rich conditiion? And are they too tight? I can fit a .102mm gauge no problemo bur not the .127mm

Im guessing the valves are not my problem , should I shim them to get closer to the middle of the spec?

thanks for the responcee

if they are in spec, leave them alone

tight valves don't make it run rich.

when the valve clearance becomes zero they become difficult to start when cold.


Bent choke puller not allowing the plunger to seat fully when pushed in causing  rich condition is my guess

Thanks Guy

FYI......It turns out that it was my kill switch, I replaced the bent choke lever to no avail, finally got it started and noticed it died when I turned the bars and it would turn off if I got anywhere near the kill switch.

Appently it was killing the engine so often that it gave me bad carb like symtoms, I pulled the guts out of tbe switch and all is good, runs like she used to and I cant wait to hit the trail tomorrow!

I am the happy camper,.........

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