I think it actually works out to be 104 CCs for a displacement if you have what I have on my spare CT90 engine. The answer to your question is a big, sort of, "It Depends". I went with a carb for a CT110 engine and down jetted from there. You would be "up-jetting" a standard CT90 carb.

So . . . what carb are you using? The best course of action for you is to buy a range of main jets and idle jets. I would start with 40-42-44 in idle jets and maybe 76, 78, 80, 82 and 84 for main jets. These are about five bucks each. If I was you, I would install the richest jet in this range first and see if the plug burns "pig rich" - a very black plug. Then start backing down two numbers on jets until your plug runs clean. You will also know if you have gone too lean when adding just a little choke at wide open throttle makes the engine go a little faster.

You really want to stay on the rich side anyway during the break in period to limit combustion chamber temperatures and keep it from seizing the piston. Now might also be a good time to consider buying a non-contact infrared thermometer.

If you can wait a day or two, I will take my 110 carb apart and tell you exactly what I have in it . . . I really cannot remember what I settled on.

Rick