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Carb Boring... is never boring!

Some boring photos of a Yamaha WR200 carb. Normally this work should be done on a 4-jaw independent chuck. I've used shims and took the carb countless times out of the chuck as to achieve the smallest runout. Then I bored the carb from 29.2mm to 31mm. Normally, the carburetor should be offset as well, as to remove the smallest amount from the base that the carb slide fits.



  1. how do you bore the curved venturi part?

  2. Hi Craig.
    In the last photo you can notice the boring operation. You only need to bore to the diameter you need. As it's only one or a couple millimeters, then the transition still stays smooth with the radius section. If you need a smoother transition then some emery cloth will get the job done. For more radical changes, you need a "ball turning" attachment for the lathe...


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