Atc 90 transmission same as atc 110?

[RawnLouver]

Have a spare 110 bottom end that i’m looking to steal a trans gear from.

My clutch let go in my 90 and locked up the trans, snapping a few teeth on a gear.

Ive ran the bike like this for a while with no issues but since i replaced the timing chain, valves, valve guides etc i’d like to replace that one trans gear while i’m at it.

Question is, are they the same or did they do any internal upgrades with the newer 110’s?

1975 atc90
1983 atc 110https://uploads.tapatalk-cdn.com/20210313/150952cb92a2acf508105cfca383aa50.jpghttps://uploads.tapatalk-cdn.com/20210313/7384f41bf6d1e57c3dde9bc8897bc235.jpg

[DAM shop]

Good question, you are just looking to replace the one gear correct? I would imagine you could go to Honda parts web site and cross check part #

[shortline10]

I believe all the points motors 1980 and older will swap , after 1981 CDI motors the cases changed and the transmission as well . Looks similar but definitely different .

[RawnLouver]

They are in fact slightly different. That being said, i believe if i were to swap the whole trans gear set from the 110 into the 90, it would work. However i Rather keep my 110 trans intact and just order a new 2nd gear online.

Here are some photos for anyone curious !

1983 atc 110 on the LEFT
1975 atc 90 on the RIGHT


https://uploads.tapatalk-cdn.com/20210315/29772200df404dd81928fac7cbd60d05.jpghttps://uploads.tapatalk-cdn.com/20210315/a134fcb05e7d288d487cd6d3ffc7aef8.jpghttps://uploads.tapatalk-cdn.com/20210315/09cf8c42f70cdcda7c33f44e207b6f3b.jpg