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!

[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.

[quad97]

I hate to say it but white smoke is generally associated with antifreeze burning, probably a head gasket.

[fmftrx300ex]

Originally posted by quad97
I hate to say it but white smoke is generally associated with antifreeze burning, probably a head gasket.

thats wht white smok is most often...unless this happened ... Sry but its a short story... one day i was mowing the lawn and was baging it so i leaned the mower back to get the grass to the back of the bag and help it like that a second and then wosh. thick white smoke duming out of the exhaustwent on until the engine finily died after i let go of the lever. then a lil flame lit up out of the muffler. went out then i tryed to start it and White smoke keeps comin out the exhaust until i give it a good yank to start it then it stoipped and ran fine... sounds like wht happened to u idk wht it is but i think i know wht u mean

[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?

[fmftrx300ex]

i woldn't ride it cuz if ur gettin more air thenyou should you could burn up your piston and that would suck

[Aceman]

Originally posted by 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?

Don't ride it, you're getting coolant in the cylinder. What is happening is you're burning it as you ride it but when you park it, it's slowly leaking into the cylinder, filling it up. That's why it wouldn't start and then when it would a bunch of white smoke bellows out. You can ruin an engine by trying to compress coolant. Trust me, I know it sucks not being able to ride but it's far better/cheaper to wait and fix it.

[f4istunna]

+1 i wouldnt ride it end up doing some damage if you do. Does it run hot?

[Dr89]

alright....looks like it'll sit for a while haha. so its the starting it thats actually hard on it? thats wht i couldnt figure out cause i was thinkin if its burning as it goes what damage could it REALLY do in the short term...but i didn't know it continued to trickle into the cylinder as it sat.

It might be running a little hot...but not off the wall...i dunno looks like im gonna have to drop it at a shop either way so it doesn't make a difference.

[chad502ex]

if you oil isn't a milky caramel with greenish tint color, then its not coolant..


by the sounds of it,... it sound like a ring seal issue... letting off the throttle after WOT will remove the pressure on the rings causing a bit less tension on them thus permitting oil to be pulled on top of the piston where it rapidly burns off as smoke...

a leak down test is an easy way of checking your ring/valve seal...


good luck

[IOWAracer]

Did you trade your KFX for this if so I would consolt the other person sounds like you got had!

Also if you keep riding it you can crack the head worse or put too much presure on the piston head and mess up the rod/crank assembly

Broc

[Dr89]

yea dude i traded straight up for it...other than all that ^^^ haha the quad is actually really solid, there aren't even any marks of it having been rolled or flipped or anything, really straight machine. im not disappointed that i traded, its still a yfz which is alot better base to build from than the kfx would ever have been.

i did talk to the guy though and he was really apologetic about it and said to bring it back down to em and they would fix it free of charge. just a pain in the a** that they're over 2hrs away :mad:

[IOWAracer]

Free is Free id push the thing there lol if i had to