Hi guys,

writing from faraway Estonia (Europe, that is).
Today I noticed a problem with my Suzuki LS650P, from 2005 - as I pulled the bike from garage, pulled out choke and started the engine, I noticed a gas leak. It was clearly running along the fuel hose and then dripping below. It seemed to be coming from some place above the petcock. When I stopped the engine, the leak stopped. Then tried again and started the engine (then without the choke), the leak started again. Afterwards I went back to garage to check and there were no signs of gas leak, so it seems that it leaked only while running.

It's my first bike and I bought it this spring and haven't been able to ride it much (besides bringing it home with my brother and rolling a bit on the little street in front of the house) as I'm waiting for my driving license. So I'm a total newb in this, but already know that a gas leak like this is definitely not okay... The bike was brought from the US in 2007 and has some small rust marks that are waiting to be dealt with. Although I don't think that there's rust under the gas tank that causes the leak, because the bike doesn't seem to be leaking when standing still. And it has been standing still in my garage for about a month before today.
The tank is rather full and oil was changed this spring.

The fuel hose seems fine, not dry or cracked. The petcock is set to "on". It was really hard to tell where did the gas come from, "above the petcock" is my best guess for now.

Do you have any ideas what could be the cause? I see that the petcock is a problem on these bikes and I have a stock one, I guess. Could that be it? Or could there be a problem or jamming in the carb? Although there was no leak on the carb itself. Or is it still the tank, somehow?
I think the leak was definitely not there when we rode it home at the end of May. Then I also put the tank full.

I would appreciate any help.

Because it happens when the bike is on, most likely the leak will be either on the diaphragm or on the outlet hose.  the diaphragm is on the backside and is vacuum operated.  there's a valve in there and allows gas to it when on.  replacing the gasket isn't hard, just use a gas proof adhesive instead.

but we'd recommend just replacing the petcock anyway.  if it's over 5 years old, depending on your type of gas (we have ethanol) it's due to fail anyway.

As you may have read on this forum, the best replacement petcock is the Yamaha 660 Raptor type. Get the genuine one and don't get a cheaper or smaller version off EBAY or similar. I'm surprised Verslagen or one of the others haven't given you the Yamaha part number.

Thank you very much for the advice and the petcock number. Haven't been able to check for some possible loose screws under the tank as I unfortunately sprained my knee and need a mechanic myself at the moment  
But what's your experience - I guess it's necessary to remove the tank to check for the tank gaskets or screws..? Otherwise I wouldn't able to see what's exactly happening down there? Or could you check these joints without removing the tank?

justin_o_guy2 wrote on 07/10/17 at 11:56:38:


 You only need to take out the 2 screws holding it to the tank and replace with the new one.  Just drain the tank first of course.  Then cut the vacuum line to the carb, fold it over and hose-clamp it.

 All this can be done from a chair, nothing other than the stock petcock needs to come off.

I had a similar gas leak on my 2005 last summer. My wife kept complaining about the gas smell when I parked it in the garage (it's lived it's 8 years that I've had it in my garage so far without a problem) but I thought it might be the o-ring gasket to the Raptor petcock. Mine tended to have gas residue at the base where the seat meets the tank. I removed and examined the Raptor, not the problem. Rode it all last summer, thinking it was primarily the gas fumes from the vent in the cap.

Fast forward to this spring, I stripped the bike to repaint and when I put it back together fuel kept puking out the vent tubes. (See my post about that for more details) I ended up thoroughly cleaning the carb and replacing the needle/seat and it solved my problem. It seems my needle/seat was slightly leaking last year and ended up completely stuck this year.

Do not lose the washers under the two screws for the petcock. They aren't really washers. Suzuki calls them gaskets. A standard metal washer will allow fuel to leak out around the screw. Trust me.  

Yamaha dealership