need your help with my quad

[cmaxx]

ok so i need your help with my 04 450r.it will rev to abotu half throttle and start popping and back firing.i cleaned the carb but i didnt help it.checked timing but it was good,what else could it be?

jetting? your sig says u have a exhaust

my 250ex did that also so then i changed the air filter(*bymyself*lol)and it ran great after that but make sure u use that foam filter spray(i prefer uni)

[fastredrider44]

Take your airbox lid off.

[UNBROKEN]

check the obvious .. do u have any air leaks ? also when was the last time u checked the valves

[fastredrider44]

Originally posted by UNBROKEN
check the obvious .. do u have any air leaks ? also when was the last time u checked the valves

Good one. Forgot about when my boot got a little crooked and ran funny. As far as valves, it would have probably been gradual. just make sure you have a clean airfiter, take the airbox lid off, and see if it gets better or worse.

[cmaxx]

ok so heres what happened when it stoped running right.i ran fine all day and then i jsut started popping all of a sudin.so i rode it back to the house really slow,and checked the timing,filter,adn my air box lid was already off.and it race fine befor so its not the jetting.it has a FCR carb if that matters.ive been trying to fix it for a few days now with no luck.

[SHIFTx450]

sounds like bad gas, like its contaminated with water or something. or a vacuum leak and/or restriction somewhere in the intake.. check your spark plug too.

[cmaxx]

well i changed the plug twice.and i dont think it could be bad gas becasue it ran fine for an hour on the same gas.im gonna pull the carb back off tomorow and check the intake and stuff for cracks and stuff.thanks for the help so far guys.

[SHIFTx450]

change the gas anyway. that way theres no IF's or BUT's or MAYBE's

[cmaxx]

i bought new vavles today they willbe in wednesday so ill put them in and see if it does the trick.

[UNBROKEN]

if u put new valves in without getting ure valve seats cut those new valves will wear FAST if i were u id have this place recut ure seats :

http://www.mxtime.com/Valve%20Seat%20Cutting.htm

[cmaxx]

yea i know im have my buddy that has a engine shop do them for me.but i borrowed a head with good valves and stuff off my buddy cause his bike broke a rod.and i didnt help my R at all.

so anything it could be?

[the predator]

check air box boot where it goes int to the box..and check where your mid pipe on your exhaust meets your head pipe.

[cmaxx]

what do i check it for?cracks?

[cmaxx]

ok i check both of them things and drained all my gas out and put in fresh gas,but still nothing.

[cmaxx]

ok so i orderd a wiring harness and cdi box and coil on ebay.

[cmaxx]

ok well guys i got it fixed,it turned out to be the stator.