Reamer will enlarge bore to .615 for stock and larger for stock appearing/modified classes

Tapered reamers enlarge the carburetor bore without grabbing and trying to lock-up that is typically experienced with a straight diameter reamer.

Please Note; Photos are shown machining internal parts on Go Kart Racing Engines, listing is for the Tapered Reamer ONLY and does NOT INCLUDE any additional tools or equipment shown in photos.

A couple things to think about, on the Clone Box Stock carburetors, most average around a .610 diameter,meaning there really is only .004 material that can be removed. If the carburetor is taken out to the maximum diameter (.615) eventually the venturi opening will change from racing or removing and re-installing the carburetor. The venturi opening can go egg shaped and the bore diameter possibly would not pass tech with a no-go.

With a tapered reamer the reamer tip is a smaller diameter than the middle of the reamer. This gradual taper is very hard to determine in a post-race tech inspection with a 100% certainty. The taper only takes place in approximately 1/8” to 3/16” overall length. If you are discussing how and what you are using to machine the bores then that could present a problem, because a known stock part would have been reamed/cut with a straight diameter tool.

Visually as you are working the carburetor from the flange side, you can see the material being removed from the carburetor body, but the venturi opening remains the same diameter. As you continue cutting eventually material will be removed from the venturi area. This whole operation is performed by hand and goes very quickly. Extreme care should be used as you are removing material from the venturi area as this diameter will change quickly once the reamer reaches that opening.