Topic: Carb problem on a '74 CB550

[Magmotor]

I just finished putting the bike back together after having a valve job done. All new everything went back on. I put new main jets on the carbs but didn't bother to do anything else to em. It now only runs on #3 &#4 cylin's. #1 & 2 aren't firing at all. They ain't ah gettten any gas. Good spark to all 4 plugs, timming is set with a light, all 4 bowls are plumb full of gas. Took the bowls back off and checked the float level adjustment, 22mm....checked valve adjustment on all intake & exhaust....re did the cam tensioner, set the dwel & adjusted the fuel air mixture. The bike fires right up before you even get your thrumb off the start button, but only on #3&4. You can grab the exhaust pipes, at the head, of #1&2 after it's been running for 3 mins, cool to the touch......pulled the two plugs and dry as a bone.....

CAn you rebuild the carbs while still on the bike?? Man I don't wannnna pull those completely off again...   what a pain...any ideas or help would be greatly appreciated. Thanks...!!

[pmpski_1]

All 4 bowls are filled with gas, but check the fuel lines\petcock for blockage anyway.

I had this problem before and after I rebuilt my carbs. After rebuilding the carbs I put those see-through inline fuel filters on the new fuel lines. I noticed that fuel wasn't going through the line to one set of carbs.  I drained the tank, took the petcock apart and cleaned the screen and blew air through all the passage ways. Put it together and it fired up on all 4 cylinders.

-Brian