So far this little engine moves in our TRX90.
Took some small frame mods under the starter to make it fit but other than that was a drop in. The wiring harness was pinned all wrong, took a few hours to repin. You will need the rotation adapter for the intake manifold to place the carb to the rear. Use the heat spacer for the carb so you have room for the petcock to fit. You will need the TB parts TRX90 throttle cable.

I also installed the race cam kit, paired with the Empire exhaust, she is a ripper and sounds amazing.

So far it is running great and shifts well.

I will note the kicker shaft is NOT 14mm, it is 13mm.

I also got rid of the included start stop switch and used sealed units that are much smaller, they were plug n play as well.

For the kill switch, I removed the key, tied the red and green together and the black/black white wires are not hooked to the tethered kill switch that acts as a key but also safely kills the engine.

I plan on buying another kick start version when available for another 90 project.