Interested in putting a motor on my mountain bike

Hello and welcome to the forum. Feel free to ask questions. lots of folks willing to help.These guys make a shift kit that will let you keep the rear disk brake. Sick Bike Parts LLC - Performance parts for your motorized bicycle

Engine Template - Motorized Bicycle: Engine Kit Forum
Classic Instructions for Building and Repairing Motorized Bicycle Engine Kits - Motorized Bicycle: Engine Kit Forum

Prolly need to see a pict of the bike to give better opinions tho.

hi and welcome to the forums, goats right, i'm new here to and have already gotten lots of help. for performance sickbikeparts also has an expansion chamber iv'e been reading up on, i can't personally afford one atm but the general consensus is they do increase performance, the shift kit goat linked you to is also considered effective from what iv'e read around here, then theres porting which iv'e been reading up on which gives a smoother ride/operation.

a guide to it is right here, make sure you read it thoroughly if you decide to do it else you'll potentially ruin your motor.

http://motorbicycling.com/f52/basics-port-polish-port-matching-16646.html

enjoy and welcome