Topic: #1 cylinder not firing

[Indy72]

#1 Cylinder not firing on a cb350f. Header pipe is cold. It appears to be getting spark and I've swapped plugs. I had the same problem a while back after it had sat for a week. I checked the bowl has fuel. I noticed one float was cracked so I ordered new float. I set the height to 21mm. I'm not sure where the others are set at, probably need to make a nipple for doing the clear tube fuel check. After replacing the float on #1 it still doesn't fire. Any recommendations what to check?

[spammasher]

Well if you are getting good spark it shouldn't be your coils, maybe your slow jet is blocked so that carb isn't getting fuel. It must be something simple so that is the good news.

[db22]

+1 on what spammasher said.  I have the same problem on my 550 project bike -- #1 won't fire for love or money.  It's down to removing the carbs for the 5th or 6th time and chasing all the fuel passages with a guitar string and a can of carb cleaner.  Ain't this fun?

[triple]

you may also have a worn slide to carb body ....
excess clearance... the air runs around the slide NOT under it to pick up the fuel
some times you MAY hear the slides rattling at idle.
Start the motor and then spray a product like " start you bastard " or similar into the bad carb and see if you can get it to fire. Next see if you can get the carb to idle by spraying some more product ( as above ).  I have a set of 750 carbs on a racer which display this issue. Not a problem for me as it doesn't need to idle but for a road bike it is a different matter...

good luck..

[db22]

aHA!!  I tried spraying Start You Bastard into the intake of #1 . . . sure enough, it fired.  That set of carbs ran well for years on another 550, but maybe the wear is finally showing.  Another fine mess to get sorted.  Thanks, Triple.

[Indy72]

Just as a follow up, I disassembled the #1 carb and cleaned all the little holes I could find. The tube with the tiny holes in the sides was a little plugged.(sorry don't have time to look the correct names). The #1 plug though sparking was fowled and not providing good spark. I bought four new plugs, reassembled carbs and it fired right up! Thanks for all the input.