I have developed a new tool. It only costs $15, and makes the
throttle rotor conversion with slots a matter of seconds. It is made
of high pressure resistant PVC, and is intended for single use. It
can be re-used if you're careful. It can be used on either size
handlebars. It can be recycled.

The 'dealer grade' throttle rotor conversion tools (7/8 r 1") are made
of tool steel, hardened, with hard chrome plating; it can be re-used
many times.

All for your convenience.