Fuel Tubes

[GS750GUY]

Hi Guys and Gals!
GS750 GUY here again.
I am in the process of rebuilding my carbs on my 78 GS750 and had to do a complete disassemble and seperation of the individual carbs. Because of a problem I discovered with the #4 carb and because these were exceptionally dirty I thought I should use the carb dip. (I know....against the advice of a lot of you I went ahead and seperated the carbs). I had no choice with the #4 carb because found it was not repairable.

However, now that I am ready to reassemble the carbs I am concerned about the quality of a tight fit of the fuel tubes between each carb. My good friend Paul from Portlad, Oregon (GS Member) told me some of you out there may have remedies for this situation. My tubes are the kind that do not use replaceable rubber "O" rings and I understand the tubes are no longer available. The tubes I have look pretty good. However I notice some very fine hairline scratching on the top of the raised ridges on a couple of the tubes. A possibility of a leak waiting to happen. Are there any tricks or things I can do to assure these will not leak when I reassemble. I thought about dabbing some kind of fuel resistant sealer of some kind between the raised rings so that the sealer is between each of the two rings on each side of the tube. I thought that since the fuel is not under any kind of pressure at all and just a gravity feed system it would have a tough time getting by both rings with some kind of fuel resistant sealer between the rings.

Have any of you had experience with this and do you have any recommendations? Is there a link or articles within the GS site that addresses this issue?

I appreciate your input and advice!
GS750Guy

[ptm]

Here's one thread with some ideas: http://www.thegsresources.com/_forum...el+carb+o-ring

It may be worth trying your existing seals as is. Mine weren't a real tight fit when I rebuilt my carbs, but they seal fine - 2 years and 10,000 mi later...

The best fix I've heard of, and the one I will try if I need to, is what Hoomgar recommends in that thread - take an exacto knife and cut out the raised ridges on the existing seals. Then put the o-rings from Robert Barr on the tube where the ridges were removed. The slots in the seal where the ridges were will hold the o-rings in place, and the o-rings themselves will seal the gas just like on the other type of fuel line connectors.

The other option is to chamfer (cut the corner off) the edge of the opening on each carb body. Then put an o-ring on the tube so it is squished against the carb body where the corner used to be. At least one person has had some success with that approach.

Good luck

[mark]

Did you have a problem before? If it ain't broke, don't fix it.

Hoomgar's fix and above ideas are good. But I'd make sure I had a problem first. Mine don't look that good, but work fine. Its your bike, of course. I've heard of others who have had success with plumbers thread tape.

[Pearson]

PTM and Mark have it right. I wouldn't over think the tube situation. I also have a '78 gs750. My fuel tubes were a little loose like ptm's were and haven't leaked a bit since my tear down and rebuild. If they weren't a problem before I say put 'em back together and move on to the next item on your list. If your 750 is anything like mine, there's still plenty more to do. :-D

[GS750GUY]

Fuel Tube Thanks

Thanks Paul, Mark, and Pearson for the great tips!!
I think I will take your advice and just put the darn thing together and stop fussing about it. If it leaks then I have a few good options. You're right I do tend to overthink things sometimes and yes I do have much to move on to. My goal is to be riding this bike by spring and I do have a whole legal pad list of items that need to be checked off first before that happens. Thanksgiving holiday is here soon and I plan on spending a good part of it at my work bench having fun.
Have a great Thanksgiving guys!!
Harold :-D