There are far more people around here that are better qualified than me to speak on this topic, but I did the 1200 conversion to mine.
It was a kit with pistons and barrels. I think that an average garage mechanic can fit this, as you've said yourself, barrels off with stock pistons and 1200 pistons and barrels on. Quite straight forward really.
I did fit a mikuni to mine at the same time, and noticed a big difference!
A GMA caliper up front helps to offset this!!!!

TD

 

I agree. I did the same with the Hammer basic kit. It took an afternoon and was straight forward.

At the risk of being a bonehead, I still recommend reading all the info on the Hammer site. Even if you don't buy their kit, they describe the whole process in great detail. It's sockets and wrenches other than the c-clips on the wrist pins.

 

What about the clutch?

 

Toss the spring plate, replace it with two steel and one friction plate and you will be good for 90+ BHP.