Airbox overflow

[iceman11]

Hi guys, i was hoping you'd be able to help me out.

I have a 1990 EX 500, the previous owners have not taking particularly good care of the bike, but other than that i have no idea how it was treated.

When i start up the bike, first of all i need to give it gas to stay alive, and then fluid (a lot!) start to come out of the air box and overflow tube. I would say its gas, however its dark (could just be dirt).

Any ideas? Is it a stuck float? perhaps it completely shut, and is making all the gas flow out the airbox?

Any help is appreciated, and any technical tips too.

[iceman11]

k i just looked at it again, and i was waiting to see if sediment would drop to the bottom of the tray i caught some of the fluid in, and nothing dropped, which means its definitely oil coming out of the air box overflow. and when it starts there is a burning smell, probably from the lack of oil? maybe?

Please guys, any help?

[skip]

alright. first off don't start the bike again right away until you figure it out. do a full oil change on the bike. it sounds like the oil is getting pushed up thought the crackcase breather and into the air box. see it the previous owner over filled the bike with oil....you would not believe how many times i have seen wantabe shady tree mechs fill the whole cranckcase with oil on an oil change.

[kneedragger88]

Likely a stuck float allowing raw gas to back into the airbox and in turn out the bottom. EX's are notorious for having the petcock leak even while sitting. So that with the float will eventually fill the crankcase with gas as well as the airbox. Check the oil for fuel contamination then try running the bike while tapping the float bowls and see if it stops. If not pull the carbs and clean them out and check the petcock while your at it. If you need someone to have a look I work cheap lighttwins@yahoo.com

[GVH]

You probably have 2 problems. Leaking petcock and stuck or holed float. If the float has craked from age it can fill with gas and never float. You can buy new ones.

Get the problem fixed and get the gas out of your crankcase. It stops lubrication and wrecks the motor.

[d00dz]

Also, I don't know if the EX500 has a crankcase breather tube (it should, right?), but check to see if it's full. If it isn't drained at least every ~15,000km and you ride it at full throttle often then it will get full and start spitting oil into your airbox.