Doing a rebuild on my '80 GS Nikki Carb, and while I was at it I thought I would see if there was anything I could gain from larger jets. Mine's a bone-stock 12A, considering trying out mechanical secondaries. Which jets should I change and to what size (I've got 93's and 160's) Thanks!

 

The .93mm primary jet translates to about .036 inches. You can purchase Holley Dominator airbleeds, or other jets, that have a 10-32 thread pitch. It's very close to the metric thread used in the carb.

I suggest going up no more than about .055 in the primaries, regardless of mech. sec. or vacuum operation.

Don't bother increasing the secondary jets. 1.6mm is about .063 SAE- a fairly large jet for the Nikki configuration.
And none of this will help you if you don't have a free flowing exhaust.

 

Thanks a lot Sterling, that's what I needed to know.