Motorcycle Repair: Carb jetting, air fuel mixture, jet needles

Question
I am in the middle of a build up of a 1980 CB750F, I have installed a header and K+N air filters, and changed the main jets from 100's to 110's but the needles are non adjustable, does this mean they are self compensating or do I need to change them too?

Keith

Answer
Hi Keith,

You may have to tune the needles (midrange). If so, shim the jet needles, or replace the needle jet/jet needle to the necessary size.

Make carburetion changes one step at a time. Perform a spark plug chop (read plugs). Make additional changes as necessary to air-fuel mixture. Continue process until properly adjusted/tuned.

Making too many changes at once leads to un-necessary corrective work. You cannot tell which change had which effect.

Respectfully,
Mark Shively