My 300ex smokes bad on startup in the morning but goes away when the motor is warmed up. I think the problem happened a few days ago when i had my 300Ex stuck in the tree and it sat on the grab bar for 15 minunites. I got it stuck in the tree pulling a wheelie and I started to go backwards and i dont have any brakes so i let it coast on 2 wheels till it hit a tree. It took the a while to get it out so do you think that could be the problem?

 

check your air box for oil.the newer models breather vent goes into the air box

 

hmm........

after mine sat upside down for 20 minutes it smoked a little then stopped..It never does it now

sounds to me like a leaky valve seat or rings.

 

No it only smokes on start ups now but it goes away and there is no hint or burning oil, not even the smell its done it 3 times.

Oh yeah I also noticed this summer that there was a little bit of oil residue around that around black thing on the right side of the cycliner. Last week i cleaned it off with degreaser and i rode it all weekend and there was no oil coming out at all so i dunno if that has something to do with it or not. Carbs are more of my thing not motors.

 

i wouldn't worry aboutit

 

usually smoking by bad rings does stop when it warms up


because the ring expands and seats.

you don't really have to do anything, i doubt it is losing compression. But i'm sure after awhile it will start smoking more and all the time.

 

dont worry about the oil around that little black plug...every 300ex i have seen leaks a little right there

 

I don't how it would be on a quad. I'm more of an automobile person myself. When the valve seats get bad, they will leak a little oil in the motor over night, or after sitting for a while, when you first start it up it will smoke for a few seconds and not necesarrily until it warms up. The ring idea sounds ok, that could be a possibility. Might not even be oil at all, might be water in the gas thats settling to the bottom of the float bowl on the carb and gettin sucked through on start up or something.

 

did you mean valve seals? If the vavle seats were leaking you would loose compression and it would run pretty bad...

Leo

 

I dunno everyone i mean comeon its a 99 i always took care of it.