Motorcycle Repair: honda jetting, air fuel mixture, ama pro racing

Question
I HAVE A XR650R 2001 AND I WAS WONDERING WHAT THE BEST SIZE OF JETS TO USE IN A STOCK CARB. IT A HAS AN EXAUST SYSTEM, AND BETTER AIR FLOW BY TAKING A FEW PARTS OUT OF THE AIR BOX, AND CHANGING THE INTAKE MANIFOLD TO A FULL OPEN ONE.

Answer
Hi Daniel,

Jetting is done by reading the spark plugs. It's a skill that is learned by experience. You often have to make several jet changes before getting the correct air-fuel mixture. That's how it is done, pal. Even with my factory roadrace MC's in AMA Pro racing.

Repsectfully,
Mark Shively