Only running on cylinders 2 & 3

[Anonymous]

Just cleaned the carbs on the 83 1100E. It was running pretty well but breaking up a bit at 8000 rpm. I tried to take care of it by running some Gumout through but then it appeared one of the needle valves wasn't sealing all the time. Had a bit of leakage on carb 1. Guess the Gumout broke some goop free.
So when I fired it up it's only running on cylinders 2 and 3. Pipes for 1 and 4 are cool as could be.
I figured unlucky coincidence and the coil for 1 and 4 went out. Checked spark by pulling the boot and lying a sparkplug across the head while cranking. Has spark. Did the same with 2 and 3 and they appear, at least visually, to have the same quality spark. Just to be sure I ohmed out the coil, it's fine. Then swapped a spare coil in and then a spare igniter. Still not running on 1 and 4.
I didn't dip the carbs (they're black and kind of wanted them to stay that way). But I did do a good cleaning on them. I'm pretty sure there wasn't any glob of silt or varnish left in there that broke loose and clogged something. Especially on two carbs at once :? .
There is fuel in the bowls on 1 and 4. I pulled the tops on carbs 1 & 4 and the slides slide freely, the linkage is working, and I double-checked that the air mixture screws are turned out two turns.
This is driving me crazy (which isn't such a long trip anyway ).
It seems it should be a fire problem, but it's getting fire. Is it possible the ignition pickup is producing spark but at the wrong time?
But my diagnostic sense tells me it's a fuel problem, that's the thing that was worked on. (You know if something breaks, what's the last thing that got changed).
Anyone seen this before, any thoughts what to look at next?
Thanks.

[Hap Call]

I know this may be a far out coincidence but could the needle valves be stuck closed, or the floats may be sticking.

Hap

[cbxchris]

Sometimes its the simple things. You did try a new set of plugs? Recently seen a very experienced mechanic thrash himself to death over a set of plugs. Being its 1&4 it does seem coil related doesn`t it?

[Anonymous]

I know this may be a far out coincidence but could the needle valves be stuck closed, or the floats may be sticking.

Hap

The bowls on 1 & 4 have fuel in them.
But I did pop carbs 1 & 4 with a hammer handle couple of times thinking there could be something stuck. Didn't help.
Thought about turning the hammer around and using the head on them but I was pretty sure that wouldn't help either in the long run .

[Anonymous]

You did try a new set of plugs?

Actually no . When I checked for fire I just grabbed an extra plug I had laying around and left the other in place.
I did at some point pull the plug on 1 and looked at it. Looked fine but was dry as a bone. I'll definately try switching plugs around though.

[bybowtie]

do you have any vaccuum on these carbs? could be a diaphram problem.. not producing enough suck to flow the gas through the carbs.....If you have gas in the float bowls its likely to be internal

[Jay B]

It doesnt matter that there is gas in the bowls. Check the floats anyhow and reset all of them. To check for vaccum pull the air box and look into each carb. Crank the motor and if the plungers are moving you have vaccum. I would bet that either you have a stuck needle or float or both.

[Anonymous]

Try swapping the coils between plug sets. Swap the low tension connectors and the plugs so the 1/4 coil is now firing to 2/3, and vice versa.

This will tell you if you are looking at coil or carby.

You could also check the pickup coils behind the right hand motor cover.

Kim

[skip]

If you can get the bike running on the two cyl that work spray some starter fluid in the carb thats dead, if that cylinder comes to life than you know its the carb. You may have to remove air box,or boots im not familar with that bike.

[Anonymous]

Looks like it was caused by me trying to get by with cleaning the carbs and not replacing the 20 year old o-rings. (They didn't look that bad, really ).
I'm guessing the original problem was caused by carbs 2 & 3 leaking so bad around the needle valve seat that 1 & 4 couldn't get enough fuel to fire.
Pulled the carbs, didn't really do anything, just checked the float height and made sure the fuel passages between carbs was clear. Put em back on and it fired up fine! Hitting on all four. Synched em and headed out for a quick spin.
5 minutes later I'm stashing it behind the van at one of the local daycares (the one my son attends actually) and calling neighbor to come and get me.
Gas was just pouring out it. So much for shortcuts.
Fortunatley the 82's carbs are sitting around freshly rebuild (with new o-rings!) so I'll put those on until I get the originals rebuild, correctly.

They say you learn from your mistakes, so I figure I'll be a frickin genius soon .