125 electrical is different - 125 has a keyed ignition and electric start.
90 electrical should be very close if not identical.
110 - 125 - 90 cc engines should all fit with minor or no mods.
You can use 185s, 200s, 200X, 250ES - 250SX front end - although anything but 200s and 185s would just be plain silly. They do fit though.
Any other questions welcomed.
BTW - what year 110 is it? 1982 110 and before are nearly identical to the ATC90. 1983 and after are different. pre 1983 110 and 90 are very similiar. Post 1983 and 125 are very similiar.
RIP - Yamahondaman!! You will never be forgotten!
RIP - Sam Brehm!! Gone but NEVER forgotten!
RIP - Sandpuppi101 - You will live on in my mind - I miss you friend!