CM91 vs C90

[hillbilly K]

I have a CM91 and a shop manual for a C90. What's the difference in the CM91 and C90?

 

[airblazer]

Different motors for starters. The CM91 has an OHC motor, where the C90 doesn’t. The CM91 was the replacement for the C90 in 1966.

 

[joel1234567]

Different motors for starters. The CM91 has an OHC motor, where the C90 doesn’t. The CM91 was the replacement for the C90 in 1966.

I think you might be confusing the C90 with the CM90.

 

[Blaine]

It is my understanding that the CM91 was the U.S. version of the C90. Same bike, but the CM91 does not have turn signals and it has a bobbed rear fender, and the C90 used a newer style front fork and the handlebars are also a different part because the speedometers have a slightly different shape, as well as the obvious mph/kph difference.

Both were the “new”(for 1966) 89cc overhead cam with aluminum head.

The CM91 still used the old style forks that were on the old 87cc iron head OHV pushrod CM90

If you’re referring to the manual in the attached picture, all of the specs and adjustments of the C90 will apply to your CM91.