'78 XS11 - Carb issues...I think

[XS_CAFE_11]

Hello all - I bought a 78 XS11 out of guys shed who let it sit there for 10 years - I have tore down the carb on several occassions and the results are always the same - I clean the heck out of it with carb cleaner, replaced jets and when it is put back together it runs....for only about an hour or two.

I then let it sit for a few hours and when I come back gas is streaming out of the carbs. I have the petcocks on "res" when it sits --- I am all sorts of confused...I am new to the whole motorcycle thing ... so any help is appreciated!! Thanks!

[DGXSER]

You need to reclean the float valve. Did you replace the float needle and the seat? Also, check your fuel lines. I first starte dusing sutomotive type fuel line and that rubber would shred on the fuel T barbs and get into the seats making them leak like crazy! When the float bowl valve does not seal off, the cabr bowl just keeps filling wiht gas until it poors out the back of the carb, and possibly the front as well into the cylinders

So check your oil for gas in it. Open the fill and smell the oil for gas fumes and / or poke a small stick into the oil and pull it out and light the stick/oil. If it lights, it has gas in it and you need to replace the oil before you run the bike anymore. The gas will dilute the oil down to the point it does not protect the bearings and can ruin them and your day/week/month!

This will also cause the cylinders that are leaking to run VERY rich and foul the plugs badly.

BTW, running the bike on reserve will use up your reserve fuel, so when you run empty, your empty and now the proud owner of a VERY heavy and not so useful pushcart!! Use ON typically.

[XS_CAFE_11]

thanks for the help! The float valve and seat were replaced with the carb rebuild - the "T" on carbs three and four is pretty beat up - I bet that's where it is coming from - I will check that out tonight and see what I can do - how difficult is it to replace the "T" fitting for the fuel lines?

[CatatonicBug]

Is the fuel flowing out of all the carbs, or just one or two of them? What you might also try is just whapping the float bowl(s) with a screwdriver handle to try to loosen the float. It may have gotten stuck in the open position, and not floated up to seal off the valve. Be careful that the float bowl gaskets don't hang into the bowl at all, because the clearance between the float and the inside edge of the bowl is really tight. That gasket tends to catch the floats if not trimmed a bit.

[XS_CAFE_11]

I have had all scenario's - I think the floats may be the issue - so the proper setting is for the floats to be all the way at the bottom of the bowl? I know that may be a stupid question - but remember I am quite a virgin at this

[CatatonicBug]

No, the floats have an actual setting to hang at when there is fuel in the carbs. I've personally never adjusted mine, so I'm not sure what the measurement is. They float in the fuel, and when the fuel gets up to a certain level, it raisies the float. That raises the needle valve, and stops the flow of fuel. If the float is stuck in the "down" position for whatever reason, the fuel keeps flowing, and you get a flood out of the carbs. The floats should NEVER hang down far enough to touch the bottom of the bowls though.

[XS_CAFE_11]

Very good - i will search and see what the measurement is supposed to be - I also have pods in place of the air box - does anyone know what type of jet needs to be placed for this...i have been told that rejetting needs to occur.

[CatatonicBug]

Very good - i will search and see what the measurement is supposed to be - I also have pods in place of the air box - does anyone know what type of jet needs to be placed for this...i have been told that rejetting needs to occur.

I can't help you there, as I am all stock. However, I search will turn up lots of info on that topic.

[bikerphil]

78 carb float height is 25.7mm with carbs upside down, gasket removed, from carb body to highest point (top) of brass float. Check the measurement on both sides of each float, make sure they are the same. Also make sure brass floats are not hitting the bowl gaskets. Bend them in slightly if needed.

[boyat68]

XS_CAFE_11 :

You do not want your floats to drop all the way down in the bowl. The reason is that the bowl is rounded at the sides and bottom and the floats tend to wedge there. You only want the floats to drop a few millimeters, just enough to allow the needle to allow fuel to flow into the bowl. Also check that the inside of the gasket is not snagging the floats. The basic idea is to ensure that the floats are centered in the bowl and only drop just enough.