Carb. Sizes?

Jon Betts · Posted: Wed Aug 01, 2001 5:48 am Post subject: Carb. Sizes?

We run a local class for new racers where the specs are

400lbs min weight
Stock 125cc motor
max 38mm carb

My son is running in this class with a stock CR125 and a 36.5mm carb as per S3 he seems to lose a lot of ground on the long straights. does this extra 1.5mm of diameter really make that much difference in performance?

Tim Pappas · Joined: 25 Jul 2001 Posts: 791 Location: Burkina Faso,

Andy Szyszkowski · Joined: 01 Aug 2001 Posts: 149

Jon,

There are likely to be other reasons for the loss of long straight speed. The larger carb all by itself is probably not your solution. You might look first at the jetting, the gearing, and the pipe, because if those aren't working well together, they still won't work together if you simply threw on the larger carb.

Andy