Replacing just the fuel fuel lines

[Azul the Cat]

The T fitting is leaking on my 79 GS750 Mikuni carbs and I was wondering how far in the carb cleaning guide I need to go to replace the fuel T and the crossover fittings? The bike is running fine other than leaking fuel from the T fitting. Is just removing them from the rack, or do I also need to remove the throttle shaft from all 4 carbs? Thanks

[Big Block]

You have to separate them of course. There is a slight chance it would upset carb balance but it is a must do anyway so I would do it and if you have trouble with idle stumble afterwards balance the carbs. I don't think you will have an issue though.

[bonanzadave]

Take a look at Mr. bwringers carb tutorial. Lots of things you won't have to do but it will give you a feel of what you will need to do. My biggest obstacle the first time was the stiff forward boots. With new flexible boots it was much easier. I got a new OEM "T" from the Suzuki dealer.

Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf (bwringer.com)

[Nessism]

To get at the Tee and fuel tubes, you need to ungang the carbs. And to do that, you need to remove the throttle shaft. An easy job, you just need to get your mind around the task. And while you are that far in, you may as well replace all the carb O-rings. I've got kits.

Some 750's use a zinc fuel tee and transfer tubes that employ replaceable O-rings. Those are easy to fix up. Others, use rubber coated Tee's and transfer tubes, which are not so easy. You can get new seals from ebay. A guy in UK sells them. Or, replace the Tee and tubes with aftermarket brass or aluminum parts, what use separate O-rings. It's a bit expensive, but well worth the effort and cost.

BTW, you will need to use an impact to remove the screws on the carb joining bar. Vessel Impacta drivers are like magic! Get a #2 & #3. Very worthwhile tools to have in your box.

[Azul the Cat]

Thanks everyone. I've got aluminum T fittings, transfer tubes, and an impact driver on the way.

[1978GS750E]

Surprised it hasn't been mentioned already, but.........if the fuel tee has been sitting dry for a while it "may" stop leaking once it gets fuel in it as the o-rings will swell.

[Azul the Cat]

Looks like I was lucky. Leaving them with fuel in it for a week, and the problem fixed itself.

[rphillips]

My CB1100F does that nearly every spring, after sitting with carbs empty for a few months. Mine will stop dripping within an hr. of getting fuel back to the fittings.... Hopefully yours will, like mine, keep sealing for yrs. to come, but if you ever have the carbs off, for any reason, good time to remember to replace those "O" rings

[Nessism]

The gas swells up the rubber. If it happens each year, you are on the ragged edge, and it's time to replace the parts.

[rphillips]

Yep, I know... Procrastinate: Unnecessarily and voluntarily delaying or postponing something... It seems to worsen with age.