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Leaking gas

  • Thread starter Thread starter Anonymous
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Anonymous

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I am to understand the little valve on my tank is no good. There is gas leaking from the air box and making a big mess. I am told there is somthing in the valve that is bad and that is why the gas is leaking but to be honest I cant find were it is coming from. I know it is leaking from the airbox "top compartment" to the bottom compartment and then driping to the gearbox. I dont know how it is geting in the airbox. I took the covers off and looked at the mouths on the carbs and they show no evedence of gas leaking. There is quite a bit of blowby in there when the bike is runing. Any ideas? If it is that little valve can anyone tell me were to get a replacment? The bike is a 79 GS850G. Thanks for the help.
 
Are you referring to the petcock (fuel control valve) on the tank? You really shouldn't be getting gas in your airbox. If gas was leaking from the carbs, it would most likely be leaking from around the area of the float bowls, at the bottom of the carbs. There is a rubber gasket between the gas tank & the petcock. Drain your tank & remove the petcock to check this gasket.
For a better diagnosis, try to pinpoint exactly where the gas is leaking from. You could have clogged carb jets, faulty fuel level floats in the carbs, a dirty fuel filter or any of a number of causes.
 
Check and see if your oil level is a lot higher than it should be. Here's my interpretation of what I think happened to me: Faulty petcock allowed gas to flow while the engine was off, carb float valves leaked a little, allowing gas into the cylinders, and then into the crankcase. I started the bike and the gas/oil mix in the crankcase came through the breather hose on top of the cam cover and into the air box. And all over the engine cases/driveway. Replacing the petcock fixed it. You didn't leave the petcock on 'prime' did you? If not, with the plenty of gas in the tank and the petcock set to 'run', disconnec the fuel and vacuum lines and see if gas leaks out.
 
First it sounds like you have two problems 1. The petcock is not working properly or you have it on prime---- Disconnect the fuel line, in the on position NO fuel should flow. If you apply vaccum to the petcock, small hose the fuel should flow. It should also flow all of the time on prime.
Even if you leave it on prime in theory it should not leak. But they do,
if the needle and seat assembly is dirty or worn it will allow fuel to flow overflowing the carbs and pouring fuel out of the carbs, and possibly into the crank case, so you need to check the oil..
Usually there are petcock repair kits on ebay also
http://www.cyclewareables.com/pages/carb_needle_seat_suzuki/suzuki_float_valves.htm
 
hmmm ok lets see. I use to keep the valve on "PRI" but latly I have kept it on "RES" when it is on "ON" or any other of the 3 options it dost leak from the tank still. Even on the "ON" position it comes out but only a drop at a time. When it is on "PRI" it also only comes out a drop at a time. When I put the valve on "RES" it flows like a bat out of hell. I can not find any fuel leakage between the tank and carbs nor is there any leakage coming from the bottom of the carbs. 100% of the leakage is coming from the air box. I took the covers off and the car "throughts" looked great. They were nice and dry with the exception of a little oil residew from the blow by. I was fully expecting them to be driping with fuel. This is why I am so stumped because the only was for it to get into the air box "from the inside" is from the blowby hose or the carb mouths. How do I tell if there is gas in the oil? I took off the oil fill cap and it smells like oil not gas. The oil level is a bit over full but nothing to call home about. Thanks for the help I look forward to geting some more suggestions.


P.S. I got this bike earlyer this year. Before I got it it sat outside sence 1996
 
It sounds like your petcock needs to be rebuilt. Gas should only flow when in the prime(pri) position. In the On or Reserve position fuel should only flow when there is vacuum applied to the vacuum hose. There should be no dripping of fuel when in the On or Reserve position without vacuum applied. The petcock should flow freely only in the Prime position (without vacuum).

Also, I would suggest only having it in the Reserve position when you need the reserve (eg: when you run out of gas when it is in the On position). That way you have a little fuel left in the bottom of the tank to get to the next gas station.
 
As usual, I got my petcock rebuild kit at a local Suzuki dealer.
 
SqDancerLynn1 said:
First it sounds like you have two problems 1. The petcock is not working properly or you have it on prime---- Disconnect the fuel line, in the on position NO fuel should flow. If you apply vaccum to the petcock, small hose the fuel should flow. It should also flow all of the time on prime.
Even if you leave it on prime in theory it should not leak. But they do,
if the needle and seat assembly is dirty or worn it will allow fuel to flow overflowing the carbs and pouring fuel out of the carbs, and possibly into the crank case, so you need to check the oil..
Usually there are petcock repair kits on ebay also
http://www.cyclewareables.com/pages/carb_needle_seat_suzuki/suzuki_float_valves.htm
Click to expand...

I had this happen to me this year guys. I had the tank flushed, screwed around with the petcock (which turned out to have nothing to do with it) and checked the in-tank fuel filter. We dropped the bottoms of the carbs and couldn't see any saturated floats or anything that looked wrong. Finally I took the carbs off and into my mechanic who went through them and found a small partical of dirt/paint/whatever that was floating around in there and would mess up the needle valve from being able to close. I 15 minute 20 dollar labor repair. I sunk hours and hours into it before we found it. It would pee gas tracks out on the road unless you were on the throttle real good and when it sat it would leak fuel out of my K&N filters.

Check for particles in the carbs!

Also, when this happened, my oil level rose a little too as mentioned and that made my worn clutch slip. Another give away. If your oil is a little full but wasn't before. Change it.
 
Jasonw24 said:
So were would you recomend I purchace a rebui;ld kit?
Click to expand...

I see them on ebay all the time. Do some seaches for GS850 and GS 850.
 
ok lets see. If the needle was stuck would iy not leak from the bowl overflow tubes? It dose not leak from them and I know they are not clogged as The y are only a week old. Also when I ride the bike there is not gas leak at all. It only leakes when it sits
 
Well I took the petcock out of the tank and tore it down. The inside looks like hell. I may just replace the whole petcock with a new one. I found one on Ebay for an 81gs850. Will it fit my 79 GS850G? Also they was 50 some od bucks for it. Is that worth it?
 
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