Gas running out of airbox

[Ebenezer]

Looking for some help. Planned on taking the XS to the Black Hills this weekend. Was riding home from work today (keep in mind it was 95 degrees out today) drove 10 miles, filled up with gas (maybe my mistake), and road the remaining 5 miles home. Went in the house, came out and gas was running out of the airbox. Shut off the petcocks and it quit running. Opened the gas tank and let everything cool off. Just turned the petcocks back on, took off the airbox and some gas was still coming out, hopefully just what was sitting in there from earlier. Put the airbox back on, took it for a quick spin, almost smoked a deer, and am now letting it sit in the garage to see if the gas stopped leaking.

I read a few threads on this already. Hopefully it was just the combination of the hot weather and a full tank of gas. Maybe this is sign to not take the bike?

[bikerphil]

Shut your petcocks off after riding the bike till you can fix your float valves properly. Your cap vent may be plugged too. Remember gas expands in hot weather, don't top off unless you keep riding.

[DGXSER]

Try adding a good dose of seafoam to your gas. Depending how low you let it get before you filled up, you might have gotten a little crap form the bottom of the tank into the carbs and the seafoam and some miles may...just may...clear it out.

Otherwise, yes, your float valves need attention.

[Ebenezer]

Gas is still leaking. I've never tore into carbs on a bike before, and I don't want to screw anything up. Is it a major tear down to work on the float valves? And if it is, am I better off going through all of them head to toe?

[bikerphil]

Not that big of a deal to work on the carbs, just a bit intimidating. In your case, there are probably some bad O-rings in your float valve seats or a stuck float. Try tapping the float bowls with a screwdriver handle, see if the leak stops. If it leaks with the petcocks in off position, those need fixing too. Don't forget to check for fuel contamination in the engine oil just in case.

[Ebenezer]

For clarification, does each petcock supply all four carbs, or just two? In my case, if either petcock is "on" gas starts to leak. If each only supplies two carbs, and you are right about the float being stuck, that would reason that more than one float is stuck. If each petcock supplies all four carbs then I might only have one float to "unstick?"

[rombat]

I have had this happen a couple of times. It seems something(rust flakes,dirt, rubber particles from inside fuel line) is lodged in the float seat. In both cases I closed the fuel shut off, and then drained all four carbs. This allows the floats to slide down and not pinch the debris in the seat. At this point I turn the fuel line to prime and leave the carb drains open. The fuel flows freely through the float seat and rinses the debris away. This worked both times for me. A lot less work than pulling the carbs apart! I installed in-line fuel filters after the first time but the small black specks in the fuel drained the second time make me suspect the original fuel line is failing after the filter.

[DGXSER]

Hey Ryan,

As to your question of how many carbs the petcocks feed, well, it depends. If you still have the OCTY (vacuum fuel valve, which sits on top of carb #2 and has four fuel lines and a vacuum line coming out of it), then the answer is one petcock can feed all four carbs in ON position. But they should not feed any when the bike is not running if that valve is working correctly.

If you do NOT have the OCTY (lots of owners scrap that thing), then one petcock would feed two carbs.

Look at THIS thread, it shows the process of dismantelling the carbs and cleaning them. Good info in there. Should make things a little less intimidating.

I would definitely lok at your oil level and see if it is higher than usual, or just change it anyway. Gas in the oil can ruin the bearings, and oil is still not so expensive I would rather rebuild the engine.

[natemoen]

Keep in mind that if you do pull the carbs and do any work on them then you will need to sync and reset the idle mixture after you re-install them.

[Lbrown311]

I like the idea of draining the bowls and running fuel thru to clean out your valve seats. If that doesn't fix it THEN you can take off your carbs. It's not difficult, just a little nerve racking the first time. Take your time and be gentle with screws and jets. If you read Carb Cleaning 101 you should be fine. Definately try to drain the bowls and run clean fuel thru them. Pay attention to the fuel to see if you have dirt or flakes in it. If so I would for sure get filters and check out your tank for rust or a peeling sealer.

[jetmechmarty]

I think you have a sticking float. The stuck float will correspond with a wet spark plug. My bike does this if the bowl goes empty. A whack with a dead blow hammer makes things right again. (It's on my long to-do list) The needle could be hanging up, or the float could be catching on something like the bowl gasket.

Mine developed a serious problem like this some time ago. The PO had broken the float post and repaired it with adhesive. When the repair failed, the carburetor leaked into the airbox. When I tried to start it, it backfired and caught fire. Not a good thing! I had the post welded.

Marty (in Seattle)

[fredintoon]

Hi Ryan,
if the in-place flow washing, whacking the carbs, feeding it seafoam and other magic tricks don't work for you, it's new needles & seats time.
Go slowly and methodically and do one carb at a time so you'll know how the carb you are working on goes back together.
Be careful to not lose the little balls & springs that click into detents in the choke pullrod.
Note there's a little bulge on the diaphragm's edge that fits in a cut-out in the body to orient it properly.
To minimise the risk of little parts getting lost, work on the carbs in a cafeteria tray.

[Ebenezer]

Thanks guys. Float in carb #2 was stuck. By the grace of God I was able to get the bowls off without taking the carbs off. Cleaned them up, put the bowls back on and no leaks!!! Hopefully it makes it through the summer and I'll have to go through the carbs this winter. Thanks again, your help is priceless.

Since the gas was running out with the bike off, does that mean my octy is bad? The way I understand it is that if the bike is off, the octy should stop the gas from running, correct?

[tcoop]

Since the gas was running out with the bike off, does that mean my octy is bad? The way I understand it is that if the bike is off, the octy should stop the gas from running, correct?

That is correct. Unless the the petcocks are set to prim then it keeps running.

[edgo]

Didn't some XS11's come with an automatic, self-cleaning air filter?