help! White smoke!!

hey guys,

i recently bought an '05 crf250r and its been great to me. I've only put maybe 5-6 hours on it since I've had it.

however, I just started it today, for the 1st time in about a week, and in no more than 20 seconds, honestly, quite a bit of white smoke was coming from the where the muffler bolts on to the exhaust pipe. The exhaust is still blowing good out the muffler, but the smoke isn't noticeable out of the back.

also, a bit of white smoke is coming from what I believe is the decompression valve? (little hole on the right side of the head)

Could running it too rich cause these areas to smoke? If so, Would turning the fuel screw underneath the carb clockwise help me?

Thanks for any info.

White smoke from the exhaust after everything has warmed up is probably steam/coolant. Maybe from a blown head gasket or something else... Loosing coolant? If you open the cap up when it's cold and start it do you see any bubbles? Any milky oil?

What "hole" on the right side of the head do you mean?

check your coolant. He means the hole on the right side of the head. Most likely time for a rebuild if the smoking does not stop.

coolant level is good. bike runs pretty good too, no significant loss of power that i can tell.

it really smells like something is melting between the muffler and exhaust pipe connection, so i pulled it all off and checked to see if everything was ok there and didnt see any sign of it.

time for a rebuild huh? I was really hoping I wasnt going to get that response.

The smoke is either coolant or oil. If it's coolant smoke, eventaully you'll have to add some to the radiator on a regular basis. If it's engine oil smoke, it could be overfilled, rings, valve guides and or vavle guide seals. Also check the "appendix hose" (with a cap on the end of it)that hangs down from the vent hose that runs from the valve cover to the air cleaner box. Over time it will fill up with oil (normal) and has to be drained. If it's full, then raw oil will migrate to the air cleaner. Don't know what your problem is, but it sounds like valve guides and or seals. If the seals are worn and the bike sets, a small amount of oil will ease past the seals and into the cumbustion chamber. Then when you start it, it will burn the small amout of oil and smoke for a few seconds and make smoke. In the meantime, check you oil very very often. You don't won't to seize an engine on the face of a jump.

If it's engine coolant, it will have kind of a sweet smell to it.

If it's engine oil, it won't smell like wood or paper or plastic burning, it will have a smooth smell to it.

i went ahead and leaned out the fuel screw about a full turn. and there it was, no more smoke!! i guess it was just runnning to rich.

man i love an easy fix!!!

but it sure did have me scared for a few days

you said smoke was coming out of the little hole in the head? (spark plug drain hole in case moisture in there) check your plug and make sure it isnt loose.. also your gas may have water in it

my plug was really loose, It amazes me that the bike was even running. i pulled the plug to check for carbon build up, and realized it. tightening it back down solved the issue there too. Thanks for looking out though, you're 100% right.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now