Gas coming out of exhaust

[Erich Z]

How normal is this? Gasoline literally was dripping from the crossover pipe this morning as I let the bike warm after a few days of sitting. medium choke, about 2k rpms. I tightened the crossover pipe collar and it seems to have stopped, but of course it has me worried. I've been getting about 55 mpg, so I don't think this is happening all the time.

Also, one of the bolts that supports the rear of the exhaust has worked its way loose. Anybody know what size bolts those are? I would just take the other in to the hardware store but I'm carless at the moment and would rather ride the bike in, but then the exhaust is too hot to mess with.

[Nessism]

Are you sure it’s gas dripping out or just condensation? If it’s the later, it’s normal. Most mufflers have a drain hole for just that purpose. Running your bike over short trips, where the condensation doesn’t have a chance to evaporate, is one common reason mufflers rot out over time.

[Dogma]

How normal is this? Gasoline literally was dripping from the crossover pipe this morning as I let the bike warm after a few days of sitting. medium choke, about 2k rpms. I tightened the crossover pipe collar and it seems to have stopped, but of course it has me worried. I've been getting about 55 mpg, so I don't think this is happening all the time.

Also, one of the bolts that supports the rear of the exhaust has worked its way loose. Anybody know what size bolts those are? I would just take the other in to the hardware store but I'm carless at the moment and would rather ride the bike in, but then the exhaust is too hot to mess with.

Um, I don't think it's ever normal to dump gas on the ground, even if you held the bike upside down and shook it. Interesting problem.

That much gas in liquid form shouldn't exist outside the tank and carb bowls. I'm thinking you have leaky petcock and at least one needle valve, just to release that much liquid.

How it got all the way to the exhaust could be a freak thing. I dunno how much overlap there is between exhaust closing and intake opening, but there will be some. If they were both open at least a little, gas could have flowed from the leaky carb, into the cylinder, and out the exhaust into the header.

Check the petcock and needle valves for proper function, and see if there is gas in your oil.

If that's not it, then one of your carbs must dumping way too much fuel when the choke is on. I don't know if that's even possible.

[Erich Z]

Petcock seems ok, had the tank off bike for a few months and nary a drop. Oil smells a bit like gasoline. How do I check the needle valve for proper function?

I just cleaned the carbs, and it has been running well, at least to me.

[Dave8338]

Check your petcock again...remove the vacuum line from the carb and let it hang off the left side of thebike, overnight. If in the morning you see a spot where it has allowed fuel to pass through the diaphragm, you in need of a new one. Some have had success rebuild them, though I'm not one of the lucky few.

[Giblet]

First, are you certain it is gas? I'm also betting on condensation.

Second, I also tried to rebuild my petcock and finally dumped it in favor of a Pingle. Don't rely on the needle valves to prevent fuel flow. It only takes a small bit of trash to cause one to stick open and the gas will invariably find its way into your crank case. They should be replaced when you clean the carbs as the o-rings get hard and eventually refuse to seal. How do you check them? I just assume if there is no gas dripping out of the carbs and plugs aren't fowling, all is well.

Third, and most importantly if you are sure you have gas in your oil DON'T ride it until you fix it. The gas will scrub the oil from the cylinder walls. This is a very common thing with GS's.

Petcock seems ok, had the tank off bike for a few months and nary a drop. Oil smells a bit like gasoline. How do I check the needle valve for proper function?

I just cleaned the carbs, and it has been running well, at least to me.

[Erich Z]

What/ where do I need to go for a Petcock if need be? I'm relatively certain it was gas not condensation, unless it was condensation that smelled an AWFUL lot like gas.

So you replace the needle valves when you clean the carbs? I'm certain I didn't do that. What do you mean by "no gas is dripping out of the carbs," where would it drip?

I'll do an oil change and see if I don't see any gas in the oil.

[Giblet]

I ordered my Pingle valve directly from Pingle. If it smells like gas, it must be gas. I've often seen kits on EBay that have needle & seat valves in them that are almost as cheap needle & seat valves by themselves. If a needle valve sticks open, gas runs out the vent tubes and will inevitably find its way into the crankcase.

However, I am totally baffled by raw gas coming out of the exhaust pipe/cross over pipe. Even if needle & seat were leaking, I can't imagine how it would get into the exhaust pipe.

What/ where do I need to go for a Petcock if need be? I'm relatively certain it was gas not condensation, unless it was condensation that smelled an AWFUL lot like gas.

So you replace the needle valves when you clean the carbs? I'm certain I didn't do that. What do you mean by "no gas is dripping out of the carbs," where would it drip?

I'll do an oil change and see if I don't see any gas in the oil.

[SqDancerLynn1]

You don't have to replace the needle if still usable. If it has a grouve in the point end ? Replace needle & seat together. When cleaning one thing you must do is replace the O ring on the needle seat -- You can get a universal replacement petcock from www.z1enterprises.com around $45-50 OEM is about $80.
If you were pouring gas out the ex pipe, would suspect it is actually from the carbs not the ex. If it was pouring that much your poor little 450 would only be running on one cylinder

[DimitriT]

The condensation that drips out on my bikes does have a smell like has or oil.

But, if its really gas, maybe its not coming from the exhaust but from the airbox
and dripping down?

[Erich Z]

But, if its really gas, maybe its not coming from the exhaust but from the airbox
and dripping down?

That's possible.

When I looked at the needle valves upon rebuild, they looked fine, but I'm no expert. The advice I always get is "replace if worn." Well, they didn't look scratched, pitted, or worn, so back in they went. I didn't set float levels since I couldn't find any info on how exactly to do it, and the Clymer's manual is absolutely awful on it, shows a black-on-black photo of a guy measuring float height somehow. I wasn't having this problem before the rebuild that i know, but I didn't really check for gas in the oil, so who knows.

I'll start with the petcock and see if that's problematic, and change the oil. If gas is still getting into the oil, I'll look into the carbs. That's the last thing I wanna do while it's still nice out though.

[Dogma]

What/ where do I need to go for a Petcock if need be?

I've had good results with stock replacement units from Z1. A lot of people like to switch to the Pingle manual shut-off, but I didn't find it necessary.

[Dave_17954]

I had the same issue with mine. My petcock diapragm was shot. I replaced the whole petcock as an assembly with a brand new one. I posted a pic in my album of my old diaphragm. look close you can see the hole in it.

[Giblet]

I've had good results with stock replacement units from Z1. A lot of people like to switch to the Pingle manual shut-off, but I didn't find it necessary.

When I cleaned my carbs I had needle/seat/o-ring in hand so I figured might as well replace the set while things were apart. You can just do the o-ring but I just figured I might as well replace the whole deal since I had them in hand. I also find the Clymer manual very confusing on the float level pictorial and the factory manual for my GK wasn't much better. It might be nice to have a picture on here somewhere with a pointer showing exactly which two surfaces to take measurements from. I just took my best guess and apparently its close enough. The Pingle is really expensive but, for me, its another one of those "you get what you pay for" things. After gas in the crankcase with two different vacuum petcocks (one a new OEM replacement), I don't trust them no matter who made them so I sleep better at night knowing the Pingle will hold. 3 years now and no gasoline leaks however, YOU have to remember to turn it off. Gets to be force of habit if you ride daily like I do.