mikuni RS36mm smoothbore with KN pod filters

[excess.11]

Just a thought on your problem and what you ve reported.........as well as checking needle /float etc..............you ve mentioned the "OFF" position on the fuel tap........
On a xs1100 standard model...the original fuel taps 3 positions are......."Prime"- (fuel flows without vac )........." Reserve "- (fuel flow needs vac)......and " On"( fuel flow needs vac..........and is also "Off".....when there is no vac ). Sorry for stating the obvious........but definately check and replace any leaking fuel tap diaphrams. When working correctly they should cut fuel flow when the motors is off , in the "On and Res " positions.I m not sure on how your reporting the "Off " position as being.... when you say it leaks..........just engine turned off ?.........or do you have a fuel tap that has a position labelled "Off" ? Once the engine vac is off..and the taps and diaphrams are in working order.........no fuel should flow........and no fuel flow means no leaks from overflowing fuel bowls.As you have reported , you may have 2 problems.........sticking carb as well as faulty fuel tap.
The kits for the taps are available on ebay.

[steptoe]

I'll back melb as well mate,, along with his advice, when you are checking the float bowls and such, if it comes to that,, if the carbs aren't brand new and they may have been "messed" with by PO,, check the float pin for straightness,, {very easily bent} roll it on  glass, you soon find out if it's bent,,
a light tap will put it right

obviously if the float has a pin hole, it will have fuel sloshing inside

and when you can, get the tap sorted,,, any adjustments made around the carbs won't affect fuel flow, that's taps, floats, needles and seats

[Jonesy]

yep, I'll 2nd melbs diagnosis

[melbxs]

Sounds like the float in the iffy carb is stuck in the open position.

It's also possible that the float has a hole in it and isn't floating.

The floats pivot on a pin and if they have been completely dry (as new carbs would) it is possible that the float has got stuck in the down position. This means the fuel keeps flowing.

First thing I would do is give the carb a couple of thumps (rubber mallet?), just to see if it frees up the float. (Don't thump it enough to break anything)

Next would be to take the float bowl off and inspect the float to see that it moves freely and that the valve closes properly when the float is up.

[matman]

My new XS had a lot of trouble with the carbs that came on it. The bloke I got it from was in the process of fixing the bike up, but told me he had trouble with the carbs and had intended to change them.

After some fooling around, I got a set of Mikuni RS36 smoothbores ($800). They come spaced for a suzuki, but have pre drilled slots and slides and guides so you can loosen the nuts and push it together to the spacing for the XS11 (or XJ too, I guess). They come with a recommendation to run K&N pods, so I jumped on ebay and got some from the US ($120) rather than a local ($400) source -I'm all for local business, but I'm not made of cash.

To tune the carbs, the K&N guide says to increase main jet size by 10%, drop the needle clip down one notch and richen the idle mix. I started the bike without adjusting the tune, and sure enough it was way too lean. So I put the needle clip down one slot, which smoothed out the mid range. The RS36 comes with a  120, 125 and 130 main jet. The 130 was installed, so I left that (I didn't have a larger jet to hand), but it seems to run fine. I turned out the idle mix by another 1.5 turns and it all seems quite nice and backfire free (I'll take it to a dyna tune or colortune next).

I took it for a bit of a ride, about 15km around town to see how it was feeling. Well, to my surprise, when I stopped the bike, the 4th carb was overflowing fuel like no one's business. I started the bike again and it overflowed more! I rode it home, and stopped the bike and it seemed to not be overflowing, but I get out of bed this morning and there is a puddle of fuel under the overflow hose.

So, perhaps some advice here from the XS pros?

I know that one of my fuel taps is dicky, and the "off" doesn't work real well - the tap that feeds the 3rd and 4th carbs. Could this cause carb overflow? Or could the richer idle mix cause carb overflow?

If you have an insight, I'd appreciate it. Otherwise, the new carbs are doing quite nicely...