So my problem is today the other day i went to start my 1996 gs500e and oil and gasoline started flowing from the airbox drain hose. quite a bit actually. So today i took it apart and the airbox had about an inch of oil/gas mixture in the bottom. It was entering through the hose connecting the airbox to the motor it appeared. Any help would be appreciated guys i havent been able to ride in a month =((.

Your needle valves have probably allowed gas to overflow into the airbox and the motor.  Then you have run the bike with gas in the crankcase.  This causes the pressure in the crankcase to throw blow-by of oil and gas through the breather tube that comes from the top of the motor.  You need to get new needle valves for your carbs and adjust and verify your float height with the clear tube from the carb drain method.  You also need to change your oil since you have gas in it.  Verify this by checking the dipstick for oil level being too high and with a gas smell.

Thank you that makes sense. However if that were the case would it allowed the bike to start on prime then die shortly after or if the fuel valve is moved to on or reserve?

Quote from: imbadnojoke on June 21, 2012, 08:56:18 AM
Thank you that makes sense. However if that were the case would it allowed the bike to start on prime then die shortly after or if the fuel valve is moved to on or reserve?

That sounds like a separate issue.  Either a bad petcock or a disconnected/leaky/kinked vacuum line to the petcock.  When you verify your float height, you should have it on prime to let the gas flow until the needles stop the flow.  Just don't leave it on prime because the needles might be too weak to stop fuel flow completely for a long period.

Okay, I'm going to check the float height and the needles in a few. I have just been at a standstill because everything is connected properly and all the hoses look to be kink free. But like i said the biggest concern is the oil/gas leaking from the airbox. I hope your needle recommendation is it. I appreciate the help tremendously.

Instructions for the float height check
http://www.gstwin.com/float_height_check.htm

Part number 33 on this fiche is the needle valve and seat.  (When I ordered mine, I ordered the more expensive one that superceded the part that's listed and it came with the o-ring #34 already on it)
carb fiche on ronayers

Float needle and tab that you need to bend slightly to adjust the float height

I cheked the float height with that technique and it appears that i need to adjust them here after dinner. We aren't getting anymore oil/gasoline in the airbox which is a plus. But the oil will be replaced this weekend as it smells like gasoline.

Again thank you very much for the help.

Ok I am about to replace my oil real quick. I checked the needles the other day buying a rebuild kit this week, its in the mail, just in case the needles looked ok. Also how would i check for a weak vacuum in the fuel lines? If its possible i should say.

Thanks so much for the help.

So the oil change was done and i checked my needles. One was perfect the other had a bit of build up on it. So we have a carb rebuild kit coming. However it starts up just fine now but randomly back fired a few times the other day, is that from maybe the needles allowing to much fuel in or what?

Backfire could be from rich or lean condition, more likely very rich due to the gas level being too high in the bowl.  I didn't have very good luck with the generic rebuild kit...had to order OEM ones.  Also, what condition are the O-rings on the needle valve seats?  If they are brittle, cracked or squared, try getting some new ones.  If that solves the problem it's cheaper than the whole needle valve set.