random gas leak, lil help?

[DeBenGuzzi]

ok so that silver thing that hangs down with a spout off it and looks almost like a petcock and the spout can swivel on it, well every once in awhile, twice now, its started leaking when I start the bike, I move the position of the spout and it stops and doesn't start up again for awhile, what could I have done or could I now do to fix this? it only seems to happen if I let it sit for awhile, few days or more and then it will do this, well twice in the last month. I'd rather not burn myself alive going down the freeway and she has me a lil worried.oh btw, it'll only leak with the bike running not sitting there or after I turn it off so its getting pumped out not dripping out through that spout, and not from the spout like all around it, I'm thinking the seal inside that swivel spout is fouled somehow.

[stormsedge]

Ben, I'm having trouble visualizing the part you describe. Do you mean the diaphram on the right underside of the tank or something elsewhere in the fuel system? k

[Tom M]

That's your fuel pressure regulator Ben. It screws on to a fitting that's screwed on to the bottom of your gas tank. It sounds like the thread sealant is leaking. The "spout" shouldn't turn. Take the tank off and drain it, unscrew the FPR, clean the threads, add some gas proof sealant, then screw the FPR back on and you should be all set.

[docc]

Tom's right. It shouldn't turn. Isn't there a locking nut you can tighten against the tank?

[DeBenGuzzi]

The Regulator doesn't move, the spout on the bottom of it does, I will look into it, but the spout shouldn't be able to turn at all? ohboy, this'll be fun taking the tank off is a pain in dabutt on the older models. Better that than a firey death, no messin around with a gas leak. Why is that spout there? there is no hose to it and gas doesn't come out of it.

I'll try and get a pic up if necessary

[stormsedge]

Ben, that's what I thought you were talking about...the "spout" shouldn't move. k

[DeBenGuzzi]

ok I fixed it, but honestly, I don't think its a fuel regulator, it looks more like a quick drain for the tank somehow, like maybe push it up and fuel pours out of the spout, I dunno, I think you guys are thinking of later models I have a 00' I took it apart and it was dirty as hell, cleaned it up real good and put a small amount of fuel resistant sealant on the rubber gaskets and put it back, let it sit for about an hour(takes 20min to setup) and the leak appears to be gone, as for NOT spinning, it looks like there is nothing there to stop it from turning its round and moves freely in its housing and ultimatly held in place by a ring clip. I really should have taken some pics huh.

 

what the hell is that thing for honeslty?

[Admin Jaap]

Have had the same problem. Just take it apart and clean it, you'll be fine.

 

My thread on it: http://www.v11lemans.com/forums/index.php?showtopic=10463

[Dan M]

ok I fixed it, but honestly, I don't think its a fuel regulator, it looks more like a quick drain for the tank somehow, like maybe push it up and fuel pours out of the spout, I dunno, I think you guys are thinking of later models I have a 00' I took it apart and it was dirty as hell, cleaned it up real good and put a small amount of fuel resistant sealant on the rubber gaskets and put it back, let it sit for about an hour(takes 20min to setup) and the leak appears to be gone, as for NOT spinning, it looks like there is nothing there to stop it from turning its round and moves freely in its housing and ultimatly held in place by a ring clip. I really should have taken some pics huh.

 

what the hell is that thing for honeslty?

 

It is a regulator and yes, it will turn. Only the friction of the o-ring is keeping it from turning. Don't make a habit of turning it though because you may cut the o-ring seal. Usually some muck from old gas will harden inbetween the o-ring and the housing causing it to leak. The best thing is clean it and just get a new o-ring. Sealant has a way getting where it shouldn't, like your injectors.

 

edit: Does any model year have manifold vacuum running to the port? It's function is to reduce pressure when not under load (closed throttle) - most reduce it by about 5 psi. Mine is just open to the atmosphere, but it would make more sense to connect it to vacuum. Anyone have a hose on theirs?

[Guest ratchethack]

edit: Does any model year have manifold vacuum running to the port? It's function is to reduce pressure when not under load (closed throttle) - most reduce it by about 5 psi. Mine is just open to the atmosphere, but it would make more sense to connect it to vacuum. Anyone have a hose on theirs?

FWIW, I ran mine for awhile connected to the manifold barbs just to see if it made any difference.

 

Absolutely none wotsoever as far as I could tell.

[DeBenGuzzi]

well I thought about not using the sealant and if I ever have this problem again it sure will be fun to clean out my mistake but I don't plan to ever take it apart again so hopefully the small amount of sealant I smeared(very small amount just a schmear) around the rings won't cause any problems. I assume this is about a bodge as I figuredyou don't want sealant in your fuel lines but I gave it almost triple its setup time so hopefully I'm fine, rode about 100mi yesterday afterwards with no ill effects. Next time I'll just clean and get new o-rings, 0-rings are easy enough to come by, if you can't find that small one at an autoparts store I suggest a hobby store, I'm sure many a RC carb uses that size who knows.

[Dan M]

FWIW, I ran mine for awhile connected to the manifold barbs just to see if it made any difference.

 

Absolutely none wotsoever as far as I could tell.

 

 

Next time I have my bike at work (maybe tomorrow) I'll hook it up to the 4 gas and see if there is less CO output with vacuum applied. My bike always seems too fat at idle even after setting mix & balancing Tbodys. I'll report what I find.

[raz]

edit: Does any model year have manifold vacuum running to the port? It's function is to reduce pressure when not under load (closed throttle) - most reduce it by about 5 psi. Mine is just open to the atmosphere, but it would make more sense to connect it to vacuum. Anyone have a hose on theirs?

The P8 manual says the port should be connected to the intake manifold. Maybe later ECUs just does the same in software, with input from the TPS.

 

I carefully turned my port to rear/inner (it was pointing front/outer) and put a 10 cm hose on it just to keep water and dirt away (right now all air here is bl**dy full of water )

[Dan M]

Next time I have my bike at work (maybe tomorrow) I'll hook it up to the 4 gas and see if there is less CO output with vacuum applied. My bike always seems too fat at idle even after setting mix & balancing Tbodys. I'll report what I find.

 

OK, here's the story. It's about 85 here today. My bike runs too rich at idle especially when the weather is hot. I have not tested the temp sensor yet.

With the regulator open to the atmosphere CO % @ idle was 5.7% (like I said, rich at idle)

With 15" of vacuum applied, CO % drops to 3.96% (more like it although I'd like to see 3.0)

So if nothing else, 1&3/4% less CO should convert using less fuel. Obviously it will only change things during closed throttle operation so the real world savings may be very small.

I do have one reservation about running manifold vacuum to it. On cars that control pressure in this manner, we often see these regulators leaking. The diaphram flexes every time the throttle is opened, and eventually tears. I'd hate to recommend this mod and have the long term effect be a leaky regulator that no one keeps in stock.