Number One Cylinder Not Firing

[Spiderman11]

Ken, the plug currently in #1 was formerly in #4. The #4 plug came from #1. Number four pipe now gets hot and number one pipe is still cold.

[Spiderman11]

Skids, thanks for giving me some more things to consider. The visual of the carbs did not find anything obviously out of place. And, to partially answer one of your questions, I have run the bike both with and without the airbox and hoses connected, with no different results. I can tell you that the previous owner apparently "lost" the little balls that hold the choke mechanism in the full and mid-range positions. So, one must hold the choke lever manually until the bike is warm enough to idle. I'm no carb expert so is there a chance this missing ball has in any way caused the #1 carb to give me a cold pipe?

[CMA1]

Spiderman,
This thread is getting so long, I forget what all has been tried
You need 3 things for combustion...
1. Fuel/Air mixture
2. A spark from ignition source
3. Compression
If this is still a problem, your #1 cylinder.... I suggest going back to the beginning......
Test the Compression on all cylinders, wet & dry
Test the spark (sounds like you got that covered)
Test the fuel .. fuel getting to carb bowl?
.. pilot system ok ?
.. slide working ok? Diaphram in good shape?
.. idle mixture screw ok? (not broken tip!)
Finally this has been suggested but I haven't seen your confirmation of test.... I know you switched plugs around BUT, have you switched #1 & #4 plug WIRES ? If you have a good spark now it probably won't make a difference...... My money is on Compression. ( Make sure the nipple is plugged well on the intake collar )Good luck
CMA1

[skids]

No, it should make no difference if you manually hold the choke open or if the detent ball does it for you. Just make sure that the set screws are also in their detents that are located on the slider bar. One more thing comes to mind. If someone has dunked the carbs in cleaning solution, the throttle plate shafts can get sticky. Because there is linkage from No. 1 to No. 2 to No. three, twisting the throttle will forcable open the throttle to the No. 1 carb, but is it returning all the way to the idle position? I brought up the point about the baffles because I have been-there-done that. The symptoms that I had were very similar and I did just about everything that you did to try and fix it until I finally replaced the exhaust system. A colortune device would hep you see where in the rpms it is running rich. If you have the pilot screw nearly all the way in clockwise, I wonder if the carb has non-stock pilot jets?

Originally posted by Spiderman11
I'm no carb expert so is there a chance this missing ball has in any way caused the #1 carb to give me a cold pipe?

[Bobxs11]

another cylinder prob

I also have a 1980 xs 11 special with the #1 cylinder having a cold pipe, so I am reading this thread with much interest.
I also have swapped plugs and plug wires, and boots with no avail. The only things that appears to be different are. My bikes pipe warms on initial start-up, once warm it stops firing. If the bike cools throughout the day then started again then the pipe stays cool. If I am riding I can here the cylinder kick in sometimes when the tach is reading over 4000rpm.
Also, there was a recent 80 degree day, I went riding and the battery went dead. Dry battery. Battery was a month old. This was the second time this season. I filled the battery and charged it. The cylinder fired, and kept firing the whole day. Figuring it was overcharging I replaced the rectifier/regulator, and battery. After all this, doesn't appear that my theory was correct. Hoping you find a cure that I can use as well.
Sorry for the lenght of reply
Bob

[TopCatGr58]

Originally posted by Spiderman11
Ken, the plug currently in #1 was formerly in #4. The #4 plug came from #1. Number four pipe now gets hot and number one pipe is still cold.

Okay, 'Spidey',

Now, swap the wires, put #1 wire on #4 cylinder and vice versa, and see if #1 gets warm and #4 stays cold. If so, then the wiring fix is not right....you can see a spark on the outside when it's not under compression, but inside the engine, under compression, there may not be enough power getting thru for it to work in the cylinder!?

But, if #1 still stays cold, then you know it's a fuel problem as the most likely culprit, providing your compression values are decent, that you don't have a blown cylinder!!

For Bob,
Well, your charging system prior to repair was apparently putting out too many amps/volts, maybe overdriving the coils, but after the repair you still have a lame #1, and both the CDI and the coils and pickups will control 1 coil and 2 spark plug wires at the same time, so hard to say why #1 was firing before the repair!? But you say that it will/can kick in over 4k rpm, which sounds like your pilot circuit is clogged, and it's not getting any fuel until you get into the higher rpms, start using the main jets!! Sounds like you need to get back into the carb and check your jets and circuits and floats and such, provided you've eliminated any vacuum leaks for that carb. Good luck to you both.
T.C.

[Spiderman11]

Guys, I agree this thread has gotten incredibly long and I apologize for monopolizing so much time and space. The first of these beasts that I owed was a brand new '79 model, right off the showroom floor. So, I never had to worry about these problems !!! Now, for nostalgia sake, I just had to go out and buy another one. Sounds like I need a better hobby, doesn't it? Anyway, I'll continue to dicker with it, including moving the #1 wire to #4, and vice versa. And......I'll shutup for a while.

[Spiderman11]

One more thing before I really shutup. I just swapped the #1 and #4 plug wires. The #1 pipe remained cold and #4 was hot as usual. Guess I'm back to looking at that #1 carb. Thanks again.

[TopCatGr58]

What monopoly?

Alright Spidey,

You're one step closer to getting it done!! And don't worry about bandwidth here, that's what this forum is all about, helping folks get their machine running, and the more information you can provide, the better we can analyze and suggest other ideas of attack. Besides, I rather talk about a problem than another oil or tire thread!!!

T.C. ....ducking for cover!

[Spiderman11]

Thanks TopCat. Am I crazy to think that I DON'T have a blown cylinder on a bike that has pretty good power and idles reasonably well (once warm) and has 13k on the odometer? No, I haven't actually checked the compression yet.

[schpiff]

Just for the h*** of it try giving the #1 cylinder a little dribble of fuel thru the vacuum nipple when its idling. I had about the same symptoms on mine when i first bought it after it had sat for a few years. Cept i had 2 cylinders staying cold...all the same symptoms..plug has fuel on it but no fire.......In my case it was extremely lean, and when I gave the dead cylinders a bit more fuel they would fire. That in turn led to getting REAL good at removing and cleaning carbs...

[Spiderman11]

Thanks for suggesting that because I had been thinking of doing that very thing. It couldn't hurt to try !!!

[uk1.1s]

Not sure if it's been suggested

Spider - anyone mention cylinder pressure??

Could it be you have a bent valve or something and the cylinder is not compressing enough on one pot....

Not sure if this would cause your trouble - but if you have access to a compression tester may be worth a look.

[Spiderman11]

Today I used a syringe to inject a little fuel through the vacuum port on #1 cylinder and the #1 pipe seemed to warm up considerably.

[Spiderman11]

I have now tested the compression and each cylinder is showing approximately 140 psi, with negligible differences between the cylinders. Does anyone disagree that I am now back to the #1 carb being the root cause of this problem?