Okay, I just installed the 17774NP (motor only) on Brahma and he started right up. Amazed? I am.
First, I took out the long screws on the OEM motor like
@Claviger stated from the starter assembly. I had to use a box end wrench as the open end wrench from Triumph was starting to strip the heads.
Then I disconnected this 12mm nut which secures the power cable to the motor.
Taking the OEM motor off was tougher than I thought as the exhaust brace was in the way. But, as the motor cover came apart, not a problem any more. I slipped the outer cover off by inserting a straight slot and twisting it to open the gap.
Here is the empty slot. Notice the corrosion on the power stud. Clean that off and apply some dielectric grease.
The new motor went on quite easy though.
I tightened the 12mm nut, recovered with the rubber cover and hit the starter button, all done.
Because I am slow, it took me about 25 minutes.