Ok, I'm turning to the experts again. I can't seem to keep the carbs on my 1971 xs1-b from "sweating" gas. I have completely rebuilt them, including setting float levels several times, and exchanging bowl gaskets at least three times. They also have new needles and seats. They seem to be "sweating" at the bowl/gasket seam. Any advice will be greatly appreciated. Thanks!
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
GAS LEAK
- Thread starter Roy
- Start date
Scottike
XS650 Member
I believe that the fuel level in your bowl should be below the top of the float bowl when the float is properly set, but it should still seal at the gasket seam regardless. I could understand a single cracked or corroded thru bowl, but two?
Edit - just how bad is the "sweat"? How is your bike running otherwise?
Edit - just how bad is the "sweat"? How is your bike running otherwise?
I would try Permatex
I may have an answer for you.
You aren't going to like it but I have a set with a same issue.
I like to think I know a little about XS carbs, but the new to me butterscotch (XS1B) carbs were doing the same thing and I couldn't win. About the third time in this is what I found.
A PO went gonzo trying to stop leaks (one screw hole stripped) and now the flanges are bent down at the ears.
These early carb flanges are thinner than the later model flanges. You can guess why they changed them.
I have a plan to correct them but I swapped in a different set of carbs "for now".
NO permatex "aviation gasket cement" It's fuel soluble and will create brand new set of problems.
You aren't going to like it but I have a set with a same issue.
I like to think I know a little about XS carbs, but the new to me butterscotch (XS1B) carbs were doing the same thing and I couldn't win. About the third time in this is what I found.
A PO went gonzo trying to stop leaks (one screw hole stripped) and now the flanges are bent down at the ears.
These early carb flanges are thinner than the later model flanges. You can guess why they changed them.
I have a plan to correct them but I swapped in a different set of carbs "for now".
NO permatex "aviation gasket cement" It's fuel soluble and will create brand new set of problems.
Last edited:
Those carb bodies are not the only ones that can be deformed with over tightening. I have heard of that issue with other carbs
They market is as
resistant to gasoline, oil and other chemicals
resists gasoline and oil
But I have not used that one so much i have an older type
black
resistant to gasoline, oil and other chemicals
resists gasoline and oil
But I have not used that one so much i have an older type
black
You go for it Jan.
I won't use that stuff near gasoline.
@Jim always has some, try and see if it'll dissolve in gas?
To be clear the issues I have seen were all from long ago. It might be different these daze?
If in fact your carb flanges are warped:
I successfully leveled the contact surfaces of my warped Yamaha DT-3 carbs using standard JB Weld. I applied, then sanded down, using a straight edge.
Four years later, they are still not leaking
.
I successfully leveled the contact surfaces of my warped Yamaha DT-3 carbs using standard JB Weld. I applied, then sanded down, using a straight edge.
Four years later, they are still not leaking
.
Last edited:
While I agree it's a poor choice for this application, Permatex AV is fuel resistant.
JB Weld application:
The carb body flanges are warped. (on mine) I guess a JB weld flattening is possible but it wouldn't be easy.
I have a different method in mind but needs a custom fixture and time to complete the job.
I can be skeptical about companies , Statements So feel free come with experiences
I have apparently smeared on more than others here more or less since the 70 ies
Everyone back then had it on like Toothpaste
And to much sometimes
Not saying it is good here But it is said to help when uneven spots and warped surfaces
Applying it On the gasket both sides
I believe that .. I have tried to reduce the use and getting leaks oil ..having to do it over again
The JB Weld can be better .. But maybe the Permatex also helps .
It is simpler apply than the JB Weld and if it is not working carbs come out
The black one i have Used is soluble in alcohol which can be a risk
2 gaskets .... ????
I have apparently smeared on more than others here more or less since the 70 ies
Everyone back then had it on like Toothpaste
And to much sometimes
Not saying it is good here But it is said to help when uneven spots and warped surfaces
Applying it On the gasket both sides
I believe that .. I have tried to reduce the use and getting leaks oil ..having to do it over again
The JB Weld can be better .. But maybe the Permatex also helps .
It is simpler apply than the JB Weld and if it is not working carbs come out
The black one i have Used is soluble in alcohol which can be a risk
2 gaskets .... ????
The JB Weld job I did on the warped carb was pretty straight-forward. Just like doing body work with Bondo.
It took about 3 applications, each sanded down.
.
I've used it in gas applications... no problems.
I first reported on my use of JB WEld in my DT-3 carb two years ago;
https://www.xs650.com/threads/repairing-pitted-fork-tubes.61159/#post-727084
.
https://www.xs650.com/threads/repairing-pitted-fork-tubes.61159/#post-727084
.
My bike runs great, couldn't get any better. The carbs build up a gas residue on the outside after a hundred miles or so. The bike stinks up the garage when I pull in and close the door. Nothing drips down onto the engine. I can't remember what the floats are set at, maybe 23mm?
Thank you Sir
I can suspect these things .. Especially since there are who knows what additives in gasoline these days.
That is why this forum have advantages ..
Reading the Sticker from the manufacturer can be Snake Oil or Gasket Cement Not always true
There is a buck to be made Truth may be secondary ... Happened Before ...
experience as gggGary He can be right ..
But it has worked for me.
Many use the center stand when parking for any amount of time. There's reasons that's so popular.
With "too many" motorcycles and lots of other gasoline powered equipment in the shed, I'm regularly wandering around following my nose and feeling under float bowls to find the "stinker". I know the lawn tractor has a fuel leak "somewhere" and spent time trying to find it recently, with no joy so far.
My back story on aviation gasket cement, grr: It has a somewhat distinctive dark brown appearance, I know of no other sealers with that look.
A gggGary barn bike wake-up turned into a brawl with seriously fuggled carb internals. A dark brown goo had plugged up all the jets passages etc., thought was typical old leaded gasoline varnish. Then when doing the rest of the fuel system found a PO had used what looked to me anyways like aviation gasket sealer in lavish amounts on the petcock to gas tank flange. My theory was the sealer dissolved and was carried to the bottom of the float bowls by slow fuel leaking over the years, and on into the jets etc. I've found similar problems from several brands of gas tank liners and the resin leached from unlined fiberglass gas tanks. Not fun and why I'm so "anti gasket sealer" in fuel systems. Like someone mentioned gasoline now contains more agressive solvents that used to be removed during distilation and sent to other industrial uses. With EPA banning a lot of those uses, those solvents need to go somewhere.
Distilation is complicated. https://www.epa.gov/sites/default/files/2020-09/documents/5.1_petroleum_refining.pdf
I don't think it would be that hard.
Apply the JB-Weld to the carb body flange. Then screw the float bowl on.
Obviously, you want to apply a mold release agent, such as Vaseline, to the float bowl first. Test the mold release first.
I'd probably remove the float bowl soon after the JB-Weld sets. I'd probably wait for the JB-Weld to fully cure before I cleaned up the excess, which I would probably do with a Dremel.
Similar threads
