Tons of fuel in the airbox..why??? GS500E '90

[D O G]

Well I bought a bike yesterday, as the title suggests, its a Goose, previously maintained by an illiterate muppet. I shouldn't have bought it, I now realise this. I am an idiot. It is going to need a full strip down to treat the rust on the frame. Meh, everyone buys a lemon at some points. I am digressing tho...

The immediate problem is that a fuel leak was discovered on the bike last night by my dad in law - it was leaking out of a hose coming from the bottom of the airbox, which had been blanked off with a rubber cap which has now split (suspect it split yesterday on the ride home).

So I have pulled it apart this morning and found that the airbox is about 1/3 full of petrol.

I presume this has accumulated over some time - spat back from the carbs maybe? I also presume that this blanked off hose should be a fuel return to somewhere. Annoyingly, the Goose service manual does not give a diagram of the airbox.

Can anyone answer the following questions...

1. Is my assumption that the pipe is a fuel return correct?
2. Whare the f*ck does it return to if fitted correctly?
3. If I'm wrong about it being a return, what should it do, and why the f*ck is my airbox 1/2 full of petrol??

Doesn't help that all my tools are on a boat in the middle of the Indian Ocean right now...

Thanks in advance!

[smegballs]

A goose??

Isnt a Goose a Suzuki 350 single???

Anyway more helpfully the same problem is on my friends GS400E.

We're running a K&N with twin manifold mounts and fuel pissed out the bottom of the K&N (it would fill the air box if one was fitted!).

Now we turned the petrol on with no filter fitted and the petrol was coming out the back of the little air passages on the carb bellmouths.

So this is more than likely an overfuelling float issue. We havent had the time to solve out GS400 at the moment but we are gonna try.....

Cleaning carb bowls

Making sure the floats actually float!!

Checking that theres no miniscule bit of crud in where the float valve seats....

If neccesary bending the tang on the float frame to get a bit more sealing pressure.

As the bike was running fine then suddenly started pissing out petrol I dont think its gonna be wear on the float needle and seat.

Heres a something to try:

1. Remove airbox.

2. Turn on fuel tap and see if petrol is pissing out two little holes on the back of each carb bellmouth.

3. Take carb bowls off in situ. (Fiddly but can be done).

4. Turn petrol tap on. Fuel should piss out the carb bowl.

5. Manually hold floats to top of their travel, cascade of petrol should stop!!

6. If it stops, then try bending the float tang a bit to give it a bit more sealing presure. Double check theres no crap on the fuel valve!!!



PS Try dropping the float bowl on one carb at a time!!


Let us know how you get on!

Rich


*edit* got any pics of the dodgey plumbing and I'l compare it to whats on our GS

[iooi]

Are you sure this is not just crap from the crankcase breather, as many bikes vent this to the air box...
And i know my divvy can puts loads of thin fuel like stuff in the air box.
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Just because my bike was A DIVVY, does not mean i am......

[D O G]

Well I think I fixed it....

The guy had his hoses mixed up - the vacuum hose from the carb to the fuel cock was venting to the air, and the air vent hose was attached to the vacuum 'bit' on the fuel cock.

Furthermore, the airbox rubbers were not correctly mounted on the carbs - huge gaps.

So I swapped the hoses, mounted the airbox correctly, clamped that drain tube where the accumulated fuel had been leaking from and it seemed to work ok. Apart from idling at 4k that is, just adjusted the throttle stop to sort that now.

Prior to all of this (i.e. yesterday), when slowing down the idle would stay at around 3k for 30-60sec or so, then fall back to correct idle.

I'm guessing the whole piece was just chucking fuel in to excess to counteract the giant gaps in the airbox, some of which was then ending up in the airbox and pooling.

Hey ho, one problem down, about 25 to go...

[Kickstart]

Hi

The carbs have got no way to lob a load of extra fuel in like that.

Most likely cause is that one of the needle valves isn't sealing correctly. Carb then overflows and a fair chance it will flow into the airbox. Tends to be an issue if you are leaving it on prime, and with the hoses the way round that you describe I presume you were using prime.

All the best

Keith
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