fuel leak between t stem and carb body and choke issue

[charbot]

hi everyone,

Im a new member, and id like to say that this site has been a huge help over the last month as ive been fixing up an abandoned '77 gs 400. I had to track down one dude to get the key, and another for the title, but with a little tlc, Ive got it running great (almost)

main problem is that I have a minor fuel leak (more of a weap, really) at the base of the carb t-stem, right where it meets the carb body. It has mikuni bs34 carbs and the tee fitting is on the right carb. Im pretty sure that this is not a removable part and there is a tiny crack where the stem is mounted into the carb body. How should I go about fixing this? JB seems an obvious quick-fix, but is there something a little nicer? Can aluminum be soldered or would it have to be welded?

Another problem: While the bike seems to idle well ( around 900- 1000)and starts with the first kick, it doesnt like having the choke "on". When I apply the choke, there is an initial surge in RPMs but after a few seconds it will die unless I give it a little throttle. turn off the choke- it idles fine again. Any ideas?

I think that Im safe in assuming that this is a carb/ fuel related issue.
I should also mention that this was someone else's "custom" job - 2 to one exhaust and 1 into 2 (?) pod air filter. not sure if it was ever properly adjusted, may or may not be relevant.

Thanks in advance

[robertbarr]

Flatout has an exploded diagram of your carbs, and plenty of replacement parts that seem to be in stock, although I don't see a fuel Tee. Your carbs should 'ungang' with little trouble, and you'll be able to get in there and see what gives.

The carbs look identical to the 80-82 450's, by the way. So there's hope out there...

That doesn't answer your question, though. I just think that unganging the carbs would make it easier to determine for sure what the source of the leak is.

[charbot]

I've had the carbs apart for cleaning. All the carb diagrams/ parts lists, including the one in my Clymer manual, show nothing about the t-stem or about it being removable. I think that the actual fitting is a seperate piece but permanently attached, like the brass float bowl drain nipples. Just the short length of fuel hose that connects the two carbs.

[pete]

Welcome to the forums!

Just had a quick look at the fiche and those carbs definitely look different to my '82 450E's.

I had the same problem as yourself, but in my case there's a T piece where the fuel host connects and it plugs into both carbs. The left carb was leaking fuel quite drastically from where the T piece slid in, so I replaced it and now there's no leak.

Maybe post a pic so we can see what you're talking about?

[charbot]

here's a image of the bike after I cleaned it up a bit. I repaired the dents and painted the gas tank, made a new cafe seat (the old one was a misshapen amateur fiberglass job, literally duct taped together) and did a basic tune up.


gs400x by charleswesleyhobbs, on Flickr


And here's the leaky t-stem. The view is looking up at the carb from below and the air intake is at the top. the main fuel line (with the tiny hose clamp) comes in from the top of the pic and is attached to the tee stem. While there is gas all over the right carb, I am 99% sure that the fuel is leaking from the seam between t-stem and carb body, and not from a bad gasket, or loose fuel hose. When I clean it all off, the leak appears first on the top of the seam, above the gaskets. It doesnt really drip, just weeps a thin film of fuel,eventually spreading across and down the float bowl. what you see is about a week's worth of leak.


carb by charleswesleyhobbs, on Flickr

[charbot]

and here's a schematic of the carb. Note that it only shows the short length of hose(part #39) between the carbs as being a separate part. The fuel tee stem is not even shown as it is on the back side of the carb body.

[BassCliff]

Greetings and Salutations!!

Hi Mr. charbot,

I know Z1Enterprises.com has a selection of fuel "T's" for different carburetors (just do a search for "fuel t" on their website). If you don't see what you're looking for, just give them a call. They are very helpful people.

Anyway, let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

[pete]

Ok I see what you're talking about!

The vacuum line on my carbs attaches to a nozzle on the left carb that is actually separate to the carb body and can be removed, yet isn't on the parts fiche as a separate item.

I suspect your T piece is a similar issue.

So, my suggestion at the moment would be to remove and ungang the carbs as suggested and see if you can remove it, and then hopefully you can see what's going on.

Try Z1 as BassCliff said as this might be something they've been asked for before.

I think you'll probably end up needing to put some sort of sealant in there and/or getting that crack repaired.

[charbot]

Bingo! you guys were dead on. it is, in fact, a separate piece. Seemed like it was in there pretty good. I was trying to be gentle and just as I was about to put it down, not wanting to damage it further, the tee slipped out. The tee is aluminum, but it has a smaller brass tip that fits into a cavity in the carb. Just a tension fitting, no sign of gasket or o-ring. I couldnt find any cracks or damage, i guess it was just loose enough to weep a few molecules of fuel. Im am applying some instant gasket compound now. When I get it all back together, probably tomorrow, Ill let you know how it works.

Any thoughts on the choke? Ive found lots of info for "runs only with choke" but not much for "runs only without choke." Fuel delivery? My petcock has some issues. BassCliff's list said "replace the petcock"- is that replace the petcock entirely, with a new " universal petcock? The stock one that bad?

Thanks for all the help so far!

[pete]

Good stuff, hopefully the gasket stuff sorts that out for you.

As to the choke, it sounds like it might be running a bit rich as the choke is actually a fuel enrichment device, meaning it adds more fuel when it's on. If this causes your bike to stall I suspect it's too rich already.

Given what you say about the PO's modifications, I'd definitely be doing plug chops and working out what the go is.

You definitely want to determine what jets are in your carbs now and how they compare to stock etc.