BAAAD Fuel Leak

[en12gine]

Maybe someone can help me out with this. Against the better wishes of my wife, I bought (what I thought to be) a steal. 1997 Katana 600 for next to nothing. It had been sitting in a garage for 2 years or so, and the guy didn't know anything about them. Well, since changing the tires and fuel lines from dryrot, I still seem to have a fuel leak problem. From other forums on here, I see that the petcock could be the culprit. Well, whoever put this together has some do-it-yourself work under the tank. I believe that my petcock is vacuum or pressure regulated or something like that. But the one I have on it now has three nipples, with one being capped off. Is that right??? So, I'm hoping a new petcock will solve the gas from leaking out of carbs 2 and 4, along with the little bit coming out of the pressure line into the air box. Any suggestions on this so my wife will quit telling me "I told you so"???

Craig in KY

[SweetJellyDount]

Suck, Flow and Blow...

I'm sure those more knowledgeable will chime in, but let me offer this up.

On my sabre, it uses vacuum pressure from the engine to open the fuel petcock and allow fuel into the carbs. It too has three openings: 1) The vacuum line. 2)The main fuel line and 3) The vent line. (Hence the title of my reply)

On mine, none of the nipples are capped off. I don't think it should be on yours either.

I'm thinking yours may operate similarly. Now the trick is to find out which one is which. Might I suggest you scour the internets and download a shop/maintenace manual for your bike. I'm sure it will have a picture of which line goes where.

Hope this helps.

[Zook]

Replace the fuel valve, AND fix the carb needles. You are risking hydrolocking the engine. Not good.

Seems to be a lot on this subject here lately...

[sdbuchert]

Definitely fix the carb needles. There shouldn't be fuel leaking from the carbs unless there is a stuck needle or a bad seal somewhere(most likely a stuck needle valve since the bike has sat). Did you rebuild the carbs? It doesn't take long for untreated gas to turn to varnish and gum up the carbs...as short a time as a few months in my experience. I'd order a rebuild kit for your petcock and fix that as well. I had a bad fuel leak on my GS1000 after a carb rebuild that was due to a stuck needle and a bad petcock diaphram. Fixing the needle stopped the leak and I rode it with a bad petcock until the new parts arrived to rebuild that too. Good luck.

[chuckycheese]

Leak

I think the first thing you need to do is figure out exactly where gas is leaking from. On a rack of carbs, there are several locations where the gas could exit and each would require a different fix. Take a really close look and let us know. Tell your wife you got a good deal and that you'll take her for a really fun ride.....if she's nice to you.

[en12gine]

Thanks for all the help. I'll start with the needles. I noticed that the line off the left side of the petcock splits into to different lines to the carbs, and the nipple on the right is blocked off...so I have to assume that the line in to the rear of the petcock is the vacuum pressure line. Can that still be a problem too? Thanks again for all the advice. I'll let you know what the wife says too!

Craig in KY

[Steve]

If the one line splits into two, it might be possible that the two lines originally went to the two fittings on the petcock. If the line on the back is a bit smaller than the others (1/4" vs 5/16") then yes, that is the vacuum line. If the Kat follows the pattern of the GS line, that hose should go to a fitting on the top of the tube leading from carb #2 to the engine. Yes, that line can be a problem, too. If the diaphragm in the petcock has a hole in it, fuel can bypass the petcock and come down the vacuum line, straight into intake tube #2, into the engine.

.

[Dave8338]

Take a look: http://www.bikebandit.com/houseofmot...m6176sch238717

"vacuum pressure"? That I have to see...

[RageZro]

Would appear this bike was only to have 2 lines from the petcock. One is a 12mm OD line the other is a bit more mysterious. The carbs have two feed lines so if the math is correct then there should be a "T" in the line from the petcock. If there is a 3rd port on the petcock and it is blocked it could be that this isn't the original petcock, in 11 years a lot can happen to a bike.

The carbs are dirty, maybe have other issues, but are for sure dirty. The big thing here is to not damage the diaphragm (#5), these are the money parts. Remove the cover (#28) very carefully, making sure that the diaphragm isn't stuck to the cover. Remember it's 11 year old rubber. You will need new bowl gaskets (#13) and o-rings (maybe). Don't freak about the o-rings, there's Grainger in Lexington at 1351 Georgetown Rd., Lexington, KY 40511
Phone: (859) 252-2302 Branch Hours: 7:30 AM - 5:00 PM (Monday - Friday)

They have metric o-ring kits in various durometers but go with the 70 durometer buna. The viton might work but viton tends to have an uncontrollable shrink rate when molded so they tend to be on the low side of the size tolerance. here is a link to metric o-ring page:

http://www.grainger.com/Grainger/wwg...gs&L1=Seals%2C

I'd drain the carbs into a some clean container that I could see what is in the bowl. To do this put some tubing on the drain outlet on the bottom of the carb bowl, turn the drain screw (#18). You can use aquarium tubing for this if that is all you have. (note: cold engine when doing this!) Look for rust, if you see rust then you need to address the tank or no amount of carb parts or seals is going to help for long if at all.

Good luck and don't feel rushed or force anything, come here and ask first, these guys are a pretty good bunch to have advise you through this process.

Take photos from all angles before breaking the rack down, work taking it down so you can pull one carb off and take this one apart by itself. Clean and rebuild it before starting the next one. Doing it this way gives you a reference if you forget where something went or in what order plus you don't mix like parts from carb to carb and keep them in order to go back into the rack the same way they were.

[KnightRider]

Would appear this bike was only to have 2 lines from the petcock. One is a 12mm OD line the other is a bit more mysterious. The carbs have two feed lines so if the math is correct then there should be a "T" in the line from the petcock. If there is a 3rd port on the petcock and it is blocked it could be that this isn't the original petcock, in 11 years a lot can happen to a bike.

The carbs are dirty, maybe have other issues, but are for sure dirty. The big thing here is to not damage the diaphragm (#5), these are the money parts. Remove the cover (#28) very carefully, making sure that the diaphragm isn't stuck to the cover. Remember it's 11 year old rubber. You will need new bowl gaskets (#13) and o-rings (maybe). Don't freak about the o-rings, there's Grainger in Lexington at 1351 Georgetown Rd., Lexington, KY 40511
Phone: (859) 252-2302 Branch Hours: 7:30 AM - 5:00 PM (Monday - Friday)

They have metric o-ring kits in various durometers but go with the 70 durometer buna. The viton might work but viton tends to have an uncontrollable shrink rate when molded so they tend to be on the low side of the size tolerance. here is a link to metric o-ring page:

http://www.grainger.com/Grainger/wwg...gs&L1=Seals%2C

I'd drain the carbs into a some clean container that I could see what is in the bowl. To do this put some tubing on the drain outlet on the bottom of the carb bowl, turn the drain screw (#18). You can use aquarium tubing for this if that is all you have. (note: cold engine when doing this!) Look for rust, if you see rust then you need to address the tank or no amount of carb parts or seals is going to help for long if at all.

Good luck and don't feel rushed or force anything, come here and ask first, these guys are a pretty good bunch to have advise you through this process.

Take photos from all angles before breaking the rack down, work taking it down so you can pull one carb off and take this one apart by itself. Clean and rebuild it before starting the next one. Doing it this way gives you a reference if you forget where something went or in what order plus you don't mix like parts from carb to carb and keep them in order to go back into the rack the same way they were.

One Is Not Hooked up on Mine, Think its a Pressure Relief. 2 Smaller one is Return . the other goes to bottom of the carbs as feed.The Hook ups in between the carbs mid range are overflow. If someone Knows what the 3rd one goes or should be hooked too Please Let Us Know > I would get Carb Kit about $140 where I live and Clean .Shouldnt have to resync if YOU do it on the rail and no Mess with sync adjust . Just a Sugesstion but Its Your BABY and Should allwasy Treat Your BABY Right =) Hope This Helps a Lil