50 miles and now a leaking carb

[zookey]

Hi guys,
My husband finally got his 79 XS1100 Special on the road after replacing carb bodies, needles, seats and bowl gaskets. He just bought this bike in May (Mothers day) with leaking carbs, went to clean them and the float pin ears were broke in 2 bodies so we ebayed a different set of carbs, replaced the needles and seats and also the gaskets between the bowls and carb bodies.

So anyway we got all the kinks out -- the bike ran great (no leaks in the carbs) and he could do 90 mph in less than 1/4 mile until he saw the Highway patrol -- or so we thought.

Now the carbs don't leak when the petcocks are in prime or run UNTIL you ride about 6-8 miles away from the house then they start leaking into the air filter. If you ride within a mile or so in each direction from the house they won't leak.

Does anyone know what will cause a running engine to flood the carbs so that they will leak?

Oh, I also put new gaskets in the petcocks and the octi.

He will appreciate any advice.

[cruiser]

Did you install in-line filters?
Debris from tank may be working through lines and keeping needle/seat from sealing

[boyat68]

zookey:

Try rapping on the sides of the carburetors with the plastic handle of a large screwdriver to see if this stops the weeping of the carbs. If this stops the problem, then this is what is happening most likely.

The floats have a tendency to stick on the forward edge of the float bowl down in the bottom of the float bowl where the bowl transitions in a gradual curve as the sides of the bowls are thicker toward the sides for strength. When you are tooling around near home, you are barely using fuel and the floats only drop a smidgen and refill the bowl quickly. When you are on the highway, you are using fuel at a greater rate, therefore your floats drop lower, before you can refill the bowl to it's higher level, and the float probably wedges and no stopping of the fuel flow occurs. This also could mean that your fuel flow is also being restricted somewhat to allow the floats to drop lower at higher throttle. There is a small tang on the back of the float that can be bent toward the parallel plane to stop the floats from dropping too far. or you could bend the floats a little downward to clear the bottom sides. You may have to do a combination of both.

There is a bench method on the site that you can use to check the closing and opening of your floats through a series of filling and emptying the carbuerators. See: http://www.xs11.com/tips/maintenance/maint20.shtml

[zookey]

Thanks for the replies guys!

As for the fuel filters........... we had total intentions of adding them into the fuel lines but we couldn't find a place to put them. The designers of the XS 1100 didn't think they needed to leave any room anywhere that we could find for the filters we had gotten.......... maybe there are some smaller ones out there somewhere.......... i don't know.

We had already set the carbs according to Ken Talbots very helpful maintanance tip. The only thing is the carbs only leak when the bike is MOVING and running. I don't know how we could have the bike moving and running and be able to tap the float bowl.......... got ya stumped too???? When he gets it back home it has quit leaking (be it riden or trailored home). We thought it could be the higher RPMS so we put it on the middle stand and started it, while it was running he put it in gear and ran it up through the gears in front of a large exhaust fan to keep it cool and it won't leak.......... this bike litterally has to be moving on the road for the carbs to leak. I don't think weep is quite the word for what these are doing........ He tinkered again this afternoon, took it for a ride, and when he came back 15 minutes later he had gone through almost a half gallon of gas and the sponge thing he had put in the air cleaner was soaked with most of the gas. This sponge is something the local bike fixer uses in airfilter boxes so the gas won't go into the oil but has the same resistance as your actual airfilter -- I can't remember what it is called.


Well after his tinkering ect today he loaded his bike on a trailor and took it off to the fix it shop down the road. There it will sit for about a month...... the guy is backed up almost a full three weeks before he can even get to it. Well, he did acomplish getting just over 50 miles on the tires this year, we will have to see if it will get to ride the road agian this year or if by the time it is finished the riding time will be over. Meanwhile he can ride his XS 750 Special (1977)

Oh the fix-it guy says there were 2 different carbs on the 1979 XS1100 Specials? Were there two different carbs run in the same year models in any given year?? Any one heard of this??

[oldyam80sg]

When i put the carbs back on my bike and the rebuilt Pingel petcocks,everything started as usual.I let the bike sit for 5 minutes and the 2 carb bodies that i didn't replace the valve seats and needles in started to weep a little gas.I tapped the sides of the bowls with a screwdriver handle and that stopped the leak.I hope i don't have your same problem,but if i do i know that i have to replace the other 2 seats and needles.But for all the times i have taken the carbs apart that doesn't seem like a hassle anymore.Good luck. PS- At least you have a shop that will look at the bike- every shop i know wont look at a bike if its not 1995 or newer!

[egsols]

The float valves are either shot or the floats are sticking.

To test what boyat68 said about the leak only occuring when you are at the higher revs and dropping the fuel level you try running the bike at idle with the petcocks turned off until she runs out of fuel. Once the bike has quit turn the fuel back on. If one or more floats are hung up you will see the fuel spilling out of the carbs.

Just make sure you don't have any fuel in your oil before you run it again.

I am chasing a similar problem and I ordered new float valves and seats for a virago. I'm going to try and install them this weekend and see if they work better.

[zookey]

Originally posted by oldyam80sg
PS- At least you have a shop that will look at the bike- every shop i know wont look at a bike if its not 1995 or newer!

I wish you luck with your carbs! Today I had to take the old carbs down to the fix it guy. He claims that there were 2 different sets of carbs on the bikes every year they were produced...... is he full of s^%t? or did they use different needles ect in the carbs for each year?

I don't know....... I do know that I know more about bikes and carburators now than I had ever planned on learning in my life time. I have said before ....... my husband does the wrenching and I do the computing! I guess that is not so tru anymore.

We are lucky....... there are actually 2 shops within 20 miles of the house that will work on the older than new bikes. Yamaha is not one of them though! Now we just have to wait the 3+ weeks to get the bike back! I was hoping for a ride this 4th of July, well maybe for Labor Day.

Originally posted by egsols

I am chasing a similar problem and I ordered new float valves and seats for a virago. I'm going to try and install them this weekend and see if they work better.

Float valves = needles? Can you replace the needles and seats with those for a different bike?? We replaced all 4 needles and seats we ordered for the XS 1100, and we did the Halbot version of setting the carbs. We left them sit for 2 days to make sure they didn't leak before reinstalling them. We also tryed the "turn off the gas" trick to see if the floats are sticking but that didn't prove to be a problem either. We are all stumped. The fix it guy is not looking forward to diving into our "mess" as he put it. But he is a good guy and hopefully it is just sticky or maybe there was some dirt in the tank (we also rinsed that out with seafoam and cleaned it real well....... always hard to know what you are getting with a used bike) that got to the needles....... I don't know........ you can only tear them apart so many times before you need someone else to take a look and see where you went wrong I guess.

Hopefully we get good news in 3 weeks when Gary can get to tearing into it. Keep the fingers crossed for us!

Thanks guys for all of your help and insight. Hopefully we will be riding this bike for another 30+ years, and you guys will be around to answer all of the questions that come up from time to time.

[egsols]

originally posted by zookey

Can you replace the needles and seats with those for a different bike??

Yes.. see this thread for details...http://www.xs11.com/forum/showthread...s&pagenumber=1

I myself just replaced the float valves and seats and found the new ones leaking as well. I think its due to the quality, or lack thereof, of the after market valves.

Hopefully I can get the new viton tipped ones in this weekend and adjusted/tested.