Dangerous Dean,
I have spent a tremendous amount of time with the RM100 & RM125 as I used to race these in my younger days. The 100 is a 50 x 50 motor & the 125 is a 54 x 54 motor. They have alot in common with each other but do have their differences. If you want some more info PM me & will share what knowledge I still remember on these.
& I would also like one of those PDFs.
DoldGuy