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04 yfz450 popping and stalling
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Posted by: creed

Went to the track today and the quad was running great. Then as i was getting ready to jump a table top i gave it som gas and it cut right out pulled off checked gas cause it was getting low, it was about a quarter tank. got it running it started to back fire and pop when i'd rev it. I pt more gas in went back out and first little roller she stalled out again. I got her going again and didnt make it half a lap before it was doing it again. Im hearing some chatter in the top, is it my valves or something else? Please help...... and thanks!!

Posted by: DarkRider3

I had something very similar happen to me yesterday. Mine was a small crack by where my clutch cable meets the case. It caused me to loose compression. Check to see if you have any oil leaking from anywhere? Good luck man.

Posted by: leveldrummer

could be valves, could be alot of things, check around your intake boot and make sure there isnt a cut or air getting in, check the oil, check your valve clearance, check your header for cracks around where it bolts up. there is really no telling what is going on.

Posted by: creed

Ok this is what ive tried so far. Pulled the TPS plug saw on another site that this was ok just cause the motor to think its running wide open, ran a lot better then took it around the yard a few times then it started doing it again. Popping and breaking up when you give it gas and backfiring when you let off Next i checked the intake boot looked cracked pulled, pulled it off but it doesnt look as though it goes all the way through. While i had the carb off i pulled the bowl off looked clean nothing that stood out but i still sprayed her with carb cleaner. I have another boot so when i get it back together i will put that one on. Let ya know when i hae more.

Posted by: Dr89

check your oil. is it empty or lower than it was the last time you checked? you might have a leak somewhere thats not so obvious thats causing what you described. heck check to see if your oil plug at the bottom of your oil tank rattled out, that could do it too

Posted by: creed

Ok cleaned the air box and the tube tothe carb both were dirty. put in new plug, old one looked black. got her back together and it still doing the same thing at about quarter throttle and up its breaking up and popping. Checked oil at track that was one of my first fears and that was looked fine. Friend has a 04 raptor and was telling me that the switch on the clutch does something simalar on his could that be it? what does it do? be nice if i can fix it without taking it to the shop!! lol!

Posted by: creed

its called a clutch switch, but im not sure what it does yet.

Posted by: Dr89

haha i dont know about that but also check your parking brake if you still have it!! if it accidently got bumped on and your trying to ride with it on your quad will do exactly what your describing as well!!

Posted by: #17YFZRACER

id say your carb is dirty as all get out. see if your jets are plugged sounds like a strong possibility.

Posted by: creed

ok checked the clutch switch, i took it of held it in and out and still nothin. also cleaned the contacts on the on off OEM kill switch still the same crap

Posted by: leveldrummer

i gotta agree with #17, sounds like your jets might be plugged up, especially if your intake boot was filthy, you probably blew some trash through your head or it got hung up in your carb. pull the carb and clean it, clean the jets extra good. check your valve clearances.

Posted by: creed

pulled the carb and it looked really clean but i didnt pull the jets i will do this next . Also ran an ohm test on the stator the pick up was good at 298, but the charging side failed the continuity test, is this my problem? i know its probably not good but would it cause my issues?

Posted by: JJs450r

sounds like valves to me mind did it just rescently and valves were bad it would start go pop bog and sputter then stall

Posted by: Dr89

yea valves would definitely cause your problems as well, i just thought it seemed odd that it happened to you so suddenly

Posted by: creed

I went to check the valve clearence and looks like the flywheel jumped a tooth forward cause the cams both line up but the flywheel mark is forward of the notch in the crankcase cover

Posted by: creed

these 2 marks are supposed to line up right

Posted by: cosinostra

Not sure on your timing, but I had the same symptoms you described and it turned out to be the billet breather on the gas cap vent line was plugged..... Basically running the thing out of gas..... Good luck..

Posted by: leas450

clean the carb and jets and check the accelerator pump's rubber diaphram. a tear in it can cause some problems like that.