Fuel Leaking

[CodyLHen]

I bought a 1977 gs750 about 4 months ago. I have been riding it all the time and enjoying the heck out of it. About a month ago I started noticing a fuel smell when I parked it. I never notice the smell when I ride. It only seems to leak a little bit and than stops. I know this because if it sits for more than a day without use the smell goes away. The fuel gathers under the carbs on top of the gear box. I have been putting a rag where it leaks to keep the fuel of the block. I have been reading on the site and it seems that carbs probably need to be rebuilt. I have also found some things about the petcock causing problems. I was just wondering if any one could weigh it on my situation. The bike runs fairly well despite the carb leak but there is a little hesitation at lower rpms.

[Nessism]

I bought a 1977 gs750 about 4 months ago. I have been riding it all the time and enjoying the heck out of it. About a month ago I started noticing a fuel smell when I parked it. I never notice the smell when I ride. It only seems to leak a little bit and than stops. I know this because if it sits for more than a day without use the smell goes away. The fuel gathers under the carbs on top of the gear box. I have been putting a rag where it leaks to keep the fuel of the block. I have been reading on the site and it seems that carbs probably need to be rebuilt. I have also found some things about the petcock causing problems. I was just wondering if any one could weigh it on my situation. The bike runs fairly well despite the carb leak but there is a little hesitation at lower rpms.

Good job of reading the archives. Sounds like time to get busy.

O-ring kit from cycleorings.com along with the large O-rings for the intake boots (assuming your boots have them).

Good luck and let us know if you have any troubles during the rebuild.

[SqDancerLynn1]

What they said, also a possibility is that the fuel T may be leaking. I had a 77GS do that. You need to take a good look at it to see where the fuel is coming from. Or we can start a barbecue - not good!!!

[CodyLHen]

Thanks for the quick replies. It seems that its going to be the hardest tracking down some of these parts. The site you provided seems to be an awsome source for rings at a good price. It doesent look like float bowl gaskets are in his kits and I was wondering where I can just get the gasket. Will I be able to order it from a OEM parts supplier with out buying a whole rebuild kit. I was also wondering what the fuel T is. I'm guessing its in the carb clean guide but I wanted some insite in to how to fix it if its the problem. Will I require another part or will this just be a O-ring in the kit. Thanks again for the info.

[Nessism]

Check Z1 Enterprises for floatbowl gaskets.

The fuel inlet to the carbs feeds through a "T" shaped tube. Unfortunately, these T fittings sometimes fail if your bike has the rubber encased version. The kind with O-rings are easy to fix so hopefully yours has that.

[chef1366]

You're lucky you didn't become a rolling molotov cocktail with that gas soaked rag on your engine.

[CodyLHen]

Thanks for the web site. It's a very good resource. As soon as I save up some money to buy parts I will keep you posted on the progress.
I use the rag when its not in use. As I said before it does not leak when its running.

[SqDancerLynn1]

If your fuel T is leaking ? just remove it & put an O ring on each end & reassemble & it will squish together & seal

[CodyLHen]

I finely found time to start my project. Carbs are off and Im starting the cleaning process. I'll be ordering new O-rings as well as the rings for the intake boots.
How should the boots on the airbox be connected? Mine are loose and slide back and forward on a inner boot.

Also when i took the tank off it did not leak fuel. I put it on a piece of cardboard and it started leaking. I bumped it a few times taking it off but not to hard. Should I just replace the petcock? The bike has 31000 miles and I have no idea how old the current one is. There 42 bucks at Z1. If anyone knows of a better deal let me know.

[SqDancerLynn1]

It would probably be a good idea to replace the petcock if it is leaking. I would also get the intake O rings & replace them. Be aware some of the early 750's did not have O rings between the boot & head & you will need to make some gaskets or replace the boots. I would also order replacement needles for the carbs (short one's). Leaking fuel is not something to mess with. Tires get very slippery when drenched in fuel along with the fire hazard. Get a cam cover gasket & Check the valve clearances while it is apart.

[CodyLHen]

I finely found time to start my project. Carbs are off and Im starting the cleaning process. I'll be ordering new O-rings as well as the rings for the intake boots.
How should the boots on the airbox be connected? Mine are loose and slide back and forward on a inner boot.

Also when i took the tank off it did not leak fuel. I put it on a piece of cardboard and it started leaking. I bumped it a few times taking it off but not to hard. Should I just replace the petcock? The bike has 31000 miles and I have no idea how old the current one is. There 42 bucks at Z1. If anyone knows of a better deal let me know.

[bwringer]

The Z1 petcock is probably about the best deal you'll find. Pretty standard to need to replace this every 20 years or so.

The boots between the carbs and airbox should be soft and pliable. Yours are old and shrunken, so order new ones from your favorite source for OEM Suzuki parts. You'll be amazed at the difference. And, of course, if the boots between the carbs and the engine haven't been replaced or are old and hardened, get some new ones.

What I've seen happen is that an old petcock accumulates some internal grunge that gets knocked loose and makes its way down into the carbs. A bit of this grunge then props open the float valves a bit, and allows the carbs to overflow.

Your petcock may also have some internal grunge that's not allowing it to seal. Replace it and ride happy.

[CodyLHen]

Yeah, I took a good look at the airbox and understand whats going on. So you can probably guess my next question. Does anyone have any suggestions on getting the old boots off? They are rock hard.

The boots between the engine and carbs are still pretty soft. The carbs came right off. I dont think they will need replacing. I will be taking them off to see if an o ring is required.

On a side note I finnaly got a look at my frame seriel number and found that it was gs750 12351. Couldent see before due to a fairing. This is different from the engine which is gs750 11169.
These are both early numbers in the run and I thought this was kinda neat. I assume that a PO must have replaced the engine at some time. Do the numbers always match?

[Nessism]

Numbers never match so don't worry about that.