yfz engine help! smoke!

[Dr89]

so i was out riding today after repacking my exhaust, everythings great for like 3hrs, then i start to see a little white smoke coming out of the exaust at times and it gets me worried. I take it back to the garage and start it up and on DECEL only white smoke pours out of the exhaust....being optimistic i thought maybe it was the rubberbands i used to hold the packing together burning up so i take the silencer off and start it again....same thing.

when idling it wont smoke, and when i rev it up it looks normal, but as soon as i let off (decel) it starts smoking like crazy again. i put it back together and rode it around the yard a bit and i thought it stopped, but once it was parked and idling again (i guess allowing time for some kind of build up??) i revved it up again and it started smoking like crazy again.

i dont wanna say its the top end because it was supposedly just rebuilt, and there is ZERO loss in power/compression. the smoke smells like gas, but when the silencer was off black liquid was kind of sparying/misting out the header like oil.

hoping for an easy fix guys help me out! i thought maybe the rings but....the symptoms are kinda funny for that and the smoke is pure white...then i thought maybe a gasket? please help!

run it a little longer. might just be the packing. I think a blown headgasket might cause it to smoke a little to. It might just be on acceleration it blows out to fast for you to notice it and on idel its not a strong enough smoke for you to see. I bet its just something in the exhaust or the packing.

The rings might be install wrong to. But i dought it. run it a few more times then worry.

[Dr89]

yea actually its been sitting a while now (engine was cool) and i go out and take it off the charger, because i'be been having problems with the battery/lighting also, and starts right up, i run it around for a while, everything seems to be perfect, no smoke at all...park it in the garage again and let it idle, still no smoke, but then i rev it up and it starts pouring out again!?? i shut it off and try to start it, it doesn't wanna start (as if its flooded) and as its trying to turn over white smoke bellows out...im not saying the smoke and the batter are related, maybe two seperate issues, but its been going that way.

i checked the voltage everywhere for the headlight problem and its all there but to much, going to order a new regulator because my bulbs blew...but anyways is there ANY possible way the electrical is some how associated with the smoking? when it starts good (full battery) no smoke....when it doesnt want to start...i get lots of smoke...weird.

[woodsrider4ever]

it doesnt smell like antifreeze does it all of your fluid levels ar efine?

[Dr89]

i cant tell what it smells like really, i thought gas but im not positive. anti freeze would smell sort of sweet am i right? and now that you say that i thought it looked lower than it did just recently....wht could the problem with that be?

[James_yfz17]

if it is burning coolant then it is probably the head gasket.

the battery problem though, did you take the lights off your bike? On the 04-05 they have a problem with that, since there is no demand for the battery(lights turned on) the stator will not recharge the battery. Lookk for a resistor kit online, they are about $60 and take 5min to install.

[PAUL TURNER]

it sounds like to me you have a bad head gasket. keep checking coolant , it should be right above the sensor. if not it is a bad head gasket.

most cases with a head gasket youl have antifreeze being pushed out of the overflow. and bike running really hot. If your antifreeze levels dont change then dont worry about that. seems like something is in the exhaust burning. Not so much motor wise. if it was motor i think it would smoke right away.

[Dr89]

the more i've researched and compared symptoms im really thinking its probably the head gasket, but still hoping it might be somethin in the exhaust....what MAJOR issues can come from me continuing riding it for a few more hours to make sure its not somethin in the exhaust before i take the head off to check the gasket??? if i keep an eye on the coolant and ride it a while longer will i be alright?


it sounds like to me you have a bad head gasket. keep checking coolant , it should be right above the sensor. if not it is a bad head gasket.

what did you mean my it should be right above the sensor? where at exactly are you talking about? thanks for the info guys keep it comin

walsh, hey would i be able to see the anti freeze like slowing trickling out of the overflow if i have it idling? if so that'd be easy to check tomorrow

[Dr89]

yea im almost positive now its the head gasket, if i dont get one until next weekend and continue to ride it like it is and keep an eye on the coolant level whats the worst that can happen?

[PAUL TURNER]

i would not ,it could blow up. about the coolant if you look in the rad. there is a senser there the coolant should not below it.