Motorcycle Repair: CBX CARBS: Your thoughts please..., stock pipes, open pipes

Question
Jan,I am on the CBX forums with you and Mike Checchini. Jack from "Old School Carbs' has my CBX carbs on his bench right now, restoring them.

We would like your input on setup and jetting. The aftermarket additions on my bike are: Tim's K&N filters, stock motor, stock pipes cut at the first weld, back the collector. Pipes are gutted / OPEN. Pipes have Kerker end-caps only, no baffles.

Jack advised that my Carbs have a Dynojet kit installed: drilled slides and Dynojet lift-springs, adjustable needles, and jets at 72 on the pilot and 100 on the mains. Jack routinely sets up his finished product at 70 and 105 on mains. Mike sets his up at 68 and 120 mains. Mike lives less than 100 miles from me and we are both at + 25 feet above sea level, located on the east coast, mid atlantic region, in VA.

Any help you can offer would be great. Thanks!
Bert

Answer
Hi Bert,
The jetting details and the needle position are very sensitive to air inlet and exhaust, and of course altitude.  There is no substitute to a dyno near you to get this right, any other tuning is guessing...  The suggestion to put in a dynojet kit will enrich the mixture earlier, so will solve a flat spot mid range, if you have one.  The jet choice you suggest sounds like a sensible start, but may need more refinement when you get to a dyno.  Good luck, and please let us know your findings,

Jan