need carb set-up advise from some pro's

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Oct 25, 2008
hi all once again need to pick your guys brain for pro advise on my carbs. putting on new amals 932's set-up with 230 main 106 n/v 3.5 slides cleaned and inspected all looks good set on middle groove for throttle needle.heres what i'm running 75 850 1.5 exhaust headers amigo dunstal aftermarket silencers electronic ing. no air box K/n air filters hose clamped to carbs .one advised up to 260 main need all you carb experts to advise .so much easier to set up with carbs off if i'm going to change any thing .any and all advise greatly apprecieted. thanks once again michael
Your main jets only come into play at full throttle. However, with the setup that you described, 260 or 270 mains might be more appropriate.

Your best bet is to put fresh plugs in it, pull it out on the highway, and do a full throttle plug chop (run it at full throttle for 5-10 seconds, hit the kill button, snap the throttle closed, and coast to the breakdown lane, remove and read the plugs).

Wouldn't blame you if you weren't comfortable with it. When I did it, it was nerve wracking - but I learned that my mains were too small (ash white plugs). I went from 3000 to 6000 rpms in 4th and did the ton - plus some. Good way to lose my license or get myself killed.
Carb set-up

Not to detract from this fine site and its priceless combined Norton knowledge, but, if you log onto click technical then click Commando then click carburettors, there is quite a long carb thread there complete with setting charts etc.. Although, the settings that you have listed are pretty much the standard for Commandos.
My Commando had the standard airbox setup and 240 mains in it when I got the bike. Seemed about right at 2500 feet elevation. Now running a single Mikuni caused I couldn't get the Amals to idle. I think most of the specs I have read call for 260 mains but modern fuels may require a slight reduction in main jet size. Have others heard this said about modern fuels? Any truth to it?
carb set-up thanks you

thanks guys for your replies that norton club site is really a good one.but i guess with carbs there no sure-fired set fix. guess i'll raise it a notch to the middle order some 260 mains and run it doing a chop test and if its lean put the larger mains in. thanks mike
Advice needed on dual mikuni vm 32 setup for 72 combat
the carbs came pre jetted and it will start up first kick but then idles erraticaly
eventually the bike quits I think from a too rich condition I think I need info on a good starting point for jetting
carb set up

hi all check out that norton club owners web site has carb settings for mik carbs too !
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