BS34SS Needle Jets

[KEITH KRAUSE]

Did you try checking/re-synching the carbs? A small error WILL make 1 cylinder run rich. If the carbs pass this test, then swap the needle jet with #4 and see if the problem follows. Seems like less trouble than looking for used carbs,parts,etc. If I understand these carbs correctly, a very small crack in a diaphragm or a diaphragm not perfectly seated will cause the piston/valve to not rise correctly resulting in a too rich mixture.
In carb troubleshooting, it's very easy to overlook a small detail. Sometimes a person can make a mistake even if he's done a particular job a hundred times. If you are relying on a mechanics experience and believe him, I understand. If you did the work yourself, I understand. I also trust my abilities but I'm open to suggestions. You may be right about the needle jet but you have'nt prooved it.

[Anonymous]

You're right Keith I haven't proved it. I checked synchronisation a couple of weeks ago 1,3,4 were the same with 2 being a minute fraction different. (Valve clearances are fine). My understanding is also the same as yours regarding the diaphragms.

I also understand what you are saying and my preference is to check the diagnosis given by my mechanic. Your thoughts are appreciated.

I have not as yet swapped needle jet locations, but my first task now is to actually confirm any wear on the needle jet and perform a full inspection. Probably a job for next weekend since this weekend is a trip to Hokitika (http://www.hokitika.net/)

Cheers

[KEITH KRAUSE]

Enjoy your trip! Let us know what happens with the bike.