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keep fouling plugs

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2005 yz250f ...... starting procedure is gas on, choke, throttle 3 full times and kick, never had a problem until just lately where it seems to foul a plug (wet plug) everytime i go to ride. changed the air filter and it helped a little, fuel screw is out 2 1/2 turns, dynojet kit

could it be my valves ? or my carb ? any help or advice would be great

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Have you checked your valves? I have seen this happen before. The bike never had a problem, then one time it is a bit harder to start, next time it craps a plug, put a new plug in and it starts right up. next time same thing, pretty soon if you keep riding it it just won't kick start and you will have to pull start. I know this cause of a buddy, I kept telling him he needed to ajust valves and he was convinced that it was jetting.......after three or for rides and me getting fed up with him fart dinking around with jetting all the time, I popped his cover and did a valve adjust and re-jetted to what it should have been and there was no more problem. funny thing is I didnt tell him and the next time we rode, he was as giddy as a school girl about how well his jetting worked from the last time out and his bike never ran like that since he got it.....I didn't have the heart to tell him I fixed his bike while it was at my house....poor guy.

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The valves always need to be in spec. They should be checked every 10-15 hours of riding.

In your case I would think it is a jetting issue. With the hot and humid weather you are running rich. Start with your fuel screw a 1/4 turn at a time. Don't forget to document your findings. Temp vs settings. That way you will now what to do next year.

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the issue mkporn was having with his buddy sounds pretty bang on to my problem ...... but i will play with my jetteing abit too

thanks guys

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If your jetting was fine before and you still ride the same areas/elevations/temperatures then it is not a jetting issue. Jetting really never changes on its' own, other than a worn needle jet/emulsion tube or needle, and this occurs gradually and only affects mid range thorttle operation, not starting.

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If your jetting was fine before and you still ride the same areas/elevations/temperatures then it is not a jetting issue.

He lives in Canada. Riding in the summer is a 20-30 degree temp change the spring and fall.

I would bet his bike ran great in the spring.

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i played with my valves a bit and my jetting and i fouled another plug ( it ran for 2 seconds with no choke and then quit)

i just noticed my hot start cable is bunged up...... would that be my problem ???

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i played with my valves a bit and my jetting and i fouled another plug ( it ran for 2 seconds with no choke and then quit)

i just noticed my hot start cable is bunged up...... would that be my problem ???

That could be it, but you would be running lean.

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about ready to dump this pile and go back to 2 stroke

fired up this morning fine, ran for a couple minutes and as soon as i dumped the choke the bike died......... the plug was wet so i took the carb off looked it over, cleaned it and jetted my main down a size........ changed the plug and started kicking with no hope then noticed gas was leaking from the carb overflow

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definitly sounds carb related. If gas is leaking out at a good rate, your floats may be stuck open.

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about ready to dump this pile and go back to 2 stroke

fired up this morning fine, ran for a couple minutes and as soon as i dumped the choke the bike died......... the plug was wet so i took the carb off looked it over, cleaned it and jetted my main down a size........ changed the plug and started kicking with no hope then noticed gas was leaking from the carb overflow

define "cleaning" a plug. Always put a new one in once it's fouled. You're getting too much gas somewhere. As far as full throttle three times, that may add to your spark plug problem. You're dumping all that raw fuel in there along with an accelerater pump. When I start my bike, Turn gas on choke, and usually it fires in one kick. As soon as it fires I dump the choke. Usually when gas starts pouring out the overflows, that's a good sign that your floats may be set too high or stuck open.

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