#2 cylinder is cold

[Flying Scotsman]

On my FJ1100 #2 headpipe is cold when I start the bike when #1 #3 and #4 get hot right away.I only ran it in the garage for a few seconds and it seemed to run fine if I opened the throttle a bit.
What would cause this ?
Carbs
Low comp
Valves
I do have spark so its not that though I will try another plug just to be sure.
I have pulled the carbs and found some junk in the filter at the N/S none of the jets are blocked but there could be more junk in #2 I did not blow it out with compressed air yet.
#2 pipe is cold anyone have any idea what to look for ?

[Bozo]

If the compression are ok, don't bypass the plug, they work differently under pressure. Also the spark plug lead could be a suspect.

All above is assuming the compressions are good, and the carbs are ok.

Some others mention the exhaust inner pipe breaking as well on the FJ1100 (I think)

What colour (or color for the yanks) is your bad cylinder plug??, when compared to others

[RichBaker]

1st thing that comes to mind is a clogged pilot jet.... does it get hot if you open the throttle a bit, get it off the idle circuit?

[Flying Scotsman]

Going to test comp next after i swap out some plugs.
I removed all the jets and they were clear.
When I give it gas 3000 rpm or so the pipe is still cold.
Plug colour is the same as #1.
I have an aftermarket pipe with single walled pipes.
Going to pull the engine to go 1200 cc soon so if its internall I can deal with it at the same time.

[RichBaker]

Yep, bad plug or plug wire, hopefully....

[Flying Scotsman]

I hope so cant afford major repairs.

[pdxfj]

Clogged "choke" circuit.

Make sure the small hole in the bottom of the bowl is clear as this is the pickup for the choke.  Also the brass tube that comes out of the carb has a small hole near the carb body.  If that becomes blocked it will also mess up the choke circuit and not allow any fuel to be picked up.

[Flying Scotsman]

Choke circuit looks good i did blow through the brass pick up tube and the top port is clear.There was a lot of crud in the filter N/S.I have extra carb parts inc carb bodies.I only have 3 bodies not sure if I have #2 would have to check.Would need to make sure there plumbed the same too.Can I swap coil wire #2 with #3 to see if #3 goes cold instead of #2 they are both on the same coil are they not.I can test the coil and plug wire and plug and if there all goodI will go back into the carbs.Thanks for any and all ideas im still learning.

[andyb]

Sure, swap the 2 and 3 plug wires and see if that moves the cold pipe around.  Easy and fast test.  You may wanna pop the plug and make sure that's okay too, just because you'll be already that far in.

From what you describe in cleaning #2 could have a plugged pilot jet, though on three cylinders it doesn't really run fine.  That or you're going to get one hell of a shock when it really does run well

[pdxfj]

You say that you ran the engine for a few seconds and I'm going to assume that was with the choke on.  ??

If you were running it with the choke on, let the bike run for a few minutes then turn the choke off and see if the #2 pipe gets hot.

One thing to keep in mind is that the choke pulls from the bottom of the float bowl.  The hole is very, very small and plugs easily.  Was there any curd in the bottom of the bowls?  Even some dried fuel can plug it.  Take your can of carb cleaner, stick the straw in the hole and spray away.  When it's clear you'll see the stream of cleaner come out where the brass tube fits in.

I'm just trying to make sure you have checked and double checked everything.  I have been in the same situation as you when bringing a 1100 back to life after it sat for almost 20 years.  One pipe was cold on start up and it wasn't plugs, wires, valves, etc.  It was the choke circuit.  Look at the pics in the middle of the page to see what we had to work with.  http://www.fjrally.com/picgallery/gallery.asp?action=browse&categoryid=15&whichpage=2

Your bike runs, and you have spark.  You're not getting fuel.  The 1100 that we brought back to life ran but not well because it has less than 100psi per cylinder.

If you're in the states, go to Harbor Freight and get their large heated ultrasonic cleaner.  Find an Amway person and buy some LOC.  Mix a gallon of cleaning solution (use distilled water), fill the ultrasonic cleaner, turn it on and run several heating cycles to get the solution really hot.  Completely disassemble the carb and put everything in the cleaner.  Run 3-4 cleaning cycles.  Rinse the carb and parts off in hot water and put it back together.

[Flying Scotsman]

Wow those carb pics are something.Its been colder so I did not go pull the carbs again or swap plugs etc.I will pull the carbs get some carb cleaner and spray through the  brass tube to see if its clear I have only used comp air in the tube.I have not measured the float hieght either but it looks good eyballing it.It will be a little warmer in a few days then I will get back out to the garage.Just knowing a blocked tube can cause a cylinder to run cold at low rpm makes it a prime suspect to look at.I just fixed a headlight/dashlight problem so I need to fix this so I can ride her when it warms up in a few days. As soon as it warms up a little I will get back out there and figure this out.

[Flying Scotsman]

Was out in the garage and its cold as hell.Just had to.Plugs,plug wires and comp are good carbs come off for a good cleaning next.Changed all the plugs and swaped #2 and #3 with no change at all.#2 pipe still cold.It should be warmer tomorrow and I am off so I will pull the carbs and see what I can figure out.
My 1200 cylinders came today and I am looking forward to upsizing to 1202 cc from 1197 cc.I am convinced my problem is #2 carb 

[Flying Scotsman]

Fixed.Carb #2 had a bad float.I set all 4 the same and voila we have 4 hot pipes  .I might go out tonight  for a quick spin just to be sure were good.

[Flying Scotsman]

Bike is running good