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CyxRyan 11-08-2012 10:58 PM

2002 YZ250 a lot of smoke and smells burnt?
I'm new to riding and new to this site so please no hate! I was riding today down my dirt road and the bike sounded great! "no bogging". I stayed 3rd gear only because the road was freshly graveled and the day before my front tire kept slipping so I didn't want to go to fast and end up falling so I took it easy this time! =D On my way back I was in 3rd revving it and going full throttle for a couple seconds "3-4 seconds" at a time.

Once I got to my drive way I noticed the smell of something burning so I looked behind me and noticed a ton of white smoke "more then usual" coming out of my exhaust. I drove my bike up my drive way in 1st gear then shut it off. I noticed there was still a little smoke coming out of my exhaust. I looked around and didn't see any leaks so I figured it was nothing. After about 10 minutes I tried to start my bike and it would not start about 5-7 kicks I would say, usually starts up in 1-2 kicks.

I did noticed when I tried to start it would start up and die quickly after so I assumed it could be the plug? I started it while giving it a little gas and it stayed on so I got on it and rode it up and down my drive way a couple times and everything seemed fine "no heavy white smoke". After I was done I shut it off and it started right up no problem. I took the spark plug out and it was black and dry. <-- "good or bad?"

I am currently running 32:1 "Klotz" and Motul 10W-30 which I put in 2 weeks ago and has about an hour or 2 on it. If anyone knows what the problem could be or might know I would more then greatly appreciated.

lankydoug 11-08-2012 11:41 PM

It's possible to get carbon build up in the pipe over time and it will catch on fire and burn out all at once. If that is the case it should run better now. Another possibility is the crank seal on the clutch side is bad and it's sucking in gear oil and burning it. Check to see if you are missing some trans oil.

wFo250 11-09-2012 08:04 AM


Originally Posted by CyxRyan (Post 673107)
I'm new to riding and new to this site so please no hate!

Hey newb....


Ha ha :D just messing with you ;) how many times have you ridden the bike? How
long had it been sitting when you bought it? Is the ratio and oil type what the PO was using? Coolant level? Sounds like you heated it up and that will make em hard to start. Main thing is find out why it got hot so you don't do any damage next ride. Riding sure is FUN eh? Love the kick in the pants and spastic powerband of a two stroke 250! Dang I think ima go get some this weekend! Oh yeah Welcome to the forum :mx

stevo450 11-09-2012 08:12 AM

Your looking at a probably blown crankcase seal and your burning tranny oil. This is most likely the case, seeing that you were running it hard for a bit and only then it started smoking....
Causes range from worn crank bearings to just an old seal. Old worn seal is an easy fix however you need to check the main bearings too as this could be an early sign that they need changing.
Hard starting.....well think of the excess oil in the crankcase now.
You need to eliminate one factor at a time to get to the root cause.
Hope this helps :)

Checking coolant, tranny oil etc should be a routine thing!!!

arnego2 11-09-2012 09:39 AM

could well be just a soaked silencer. if I run the bike hard back home on street I get a smoking silencer when killing the engine, good indicator for a soaked silencer :)

If the bike smokes a lot when running specially with a fully warmed up engine (7 min at least) you looking at a blown crank seal or a blown head O ring depending on the color. Good idea is to run ATF as when burned off gives you a particular smell so you know its the seal.

coryR 11-09-2012 10:41 AM

im not sure of the exact situation but i know some times when i repack the silencer and run it wide open for a while after a fresh repack it will smell like somethings burning and a bit of smoke or steam will be coming out of the exhaust when i shut it down

stevo450 11-09-2012 10:43 AM


Originally Posted by coryR (Post 673161)
im not sure of the exact situation but i know some times when i repack the silencer and run it wide open for a while after a fresh repack it will smell like somethings burning and a bit of smoke or steam will be coming out of the exhaust when i shut it down

For everyone with a similar comment... This is quite normal:) imo

CyxRyan 11-09-2012 09:45 PM

The 2nd owner who I bought the bike off of bought it in July and took it out on trails through out July-September and in October is when I bought it from him because he wanted to get a snowmobile. I am running the same thing that he was on the bike besides he was running 30:1 but said that it was spitting up to much oil out of the back so I went to 32:1.

I use 93 Octane gas which is the best I can get around here and road it maybe 15 times which would be about maybe 2 hours of riding time. I may be new to dirt bikes but im not dumb! I did my research on everything to know about 2 strokes before I bought! I do check my radiator fluid every time I ride and do check my trans oil as well. I did drain my oil after that happen and it still looked like new and no signs of leaks anywhere. What I have noticed is that the exhaust still has a ton of oil that leaks out the end and in the middle where the rubber mount that connects to the silencer to the pipe. I also noticed that the rubber seal was loose and oil around the whole area.

---------- Post added at 11:45 PM ---------- Previous post was at 11:23 PM ----------

Also I know the engine will need to be rebuilt eventually and my plan is to rebuild before season starts because I know im not going to be able to ride the bike like its suppose to because im such a noob! but learning pretty fast I would say ^_^

CyxRyan 11-11-2012 03:47 AM

I will let you all know Monday about my bike once I get a few things from the shop because its not open on Sunday and the past 2 days I have worked doubles =/

CyxRyan 11-13-2012 07:17 AM

UPDATE!!! So I put new radiator fluid in, new tranny oil, new spark plug. Cold start took 2 kicks let it run for about a minute half with choke on only because after a minute I took it off and the bike was bogging a little bit. I let it warm up few minutes then took it for a spin. No smelly white smoke from the exhaust so hopefully it wasn't anything to bad that caused the white smoke. I chased my geese around which was hilarious but now my bike is all muddy ='/ sniff sniff!

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