Carb Jetting

Not open for further replies.
Dec 9, 2008
I am reworking the single 34mm Mikuni carb on my MK III. So far I have gotten two different jet settings. Which one would be the best to start with since I live in Southern California.

One theory is.
Needle Jet P2 159
Needle 6DH3
Pilot Jet 40
Main Jet 240

When you order a new carb from Sudco for the Norton, this is what you get.

Needle Jet P0-159,
Needle 6DH3,
Pilot Jet 35
Main Jet 250

Carb jetting is a bit new for me, so I'm not sure if there is actually much of a difference, or which way to go.
both are very close to being correct, I would start with the top one as it is slightly richer in the mid range,from this forum I have noticed most people use a#3 slide, the #2.5 seems to give a slightly rich low load cruise,about 60~70 mph you may notice a slight surging. When you get it correct the mid range will be good but you will run out of puff at about 100mph

my one is set like so
#3 slide
6dh4 needle
159 p2
230 main
3 air jet
Iam not sying my settings are perfect for your bike but you can see that both of the settings you have are very close
Not open for further replies.