The swap to a predator 212 is very easy and I was able to accomplish it within 2 days using a rotary tool and a drill. However I had aligned the motor incorrectly and had to go back in and correct this with my rotary tool. After I went on a ride and blew the OEM bearings on the back wheel.
I recommend changing those bearings as they are not great and left me with a 30 minute walk back. I used these bearings
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
I would still recommend using the adapter plate that PMR makes which is about 40 dollars plus shipping as the adapter is much more fool proof and allows for adjustment to alignment.
I opted to use a centrifugal clutch because I have had good experience with them and they can cost much under 100$. I found my clutch at a farm and fleet (they guessed what I was doing haha) the clutch was a Comet brand 12 tooth that is rated up to 8 hp and cost 50$. I was able to get by using the original chain by using a punch and hammer to shorten its length.
Also the throttle lever on the predator 212 will need to be modified by removing the friction washer that sits under the lever and by putting an extension spring onto the lever to another part of the motor to give better tension to the doodlebug throttle twister.
all this will give you a doodlebug that goes 35 mph with the stock 70 tooth sprocket the speed can be adjusted with a gearing change.
