Glad to see that there are others like me.
 
I bought an engine kit on ebay, it came with the accessories, the cdi, the charger etc. that meant that the only voltage conversion I had to worry about was switching the light bulbs and the battery.
 
the engine will bolt in without a problem, but there are things to negotiate around. you may need to replace the chain, as the new engine is fitted with a larger 428 sprocket and I think the stock is a 420. I am using the 420 rear sprocket with the 428 chain, it doesnt seem to be a problem.
 
If you use the gears that come with it, think about starting in 2nd gear the 1st time you give it a shot.
 
you will also need to get a clutch cable that is specific for the engine. I was able to find one on ebay for about $20.
 
besure that you get an oil cooler too. I guess that without it, no oil gets to the top of the motor, meaning that it will burn out in a few hundred miles.
 
when you get to the exaust and carb alignment, you will have some problems. The stock exaust pipe goes right over the top of the oil cap. also, the intake paterns are alittle bit off making the air filter difficult to line up.
 
I had a local shop weld me a new exaust pipe, using parts from the old one (also the intake), so that it would line up. I told them to put the pipe below the engine. This caused a problem with the brake pedal since it wasnt designed to have an exaust going through it. so, I kinda screwed up by giving them instructions rather than just saying "make sure I can change the oil when you are done". A friend with a welder could probably do the whole thing for a 12 pack, I think I paid $150.
 
Also, since the displacment is larger, the exause may hold up some of the horse power. I got around this by removing the silencer on the muffler. It is loud, but not as bad as the harleys that go down the street, so I think it is all okay.

It worked out good though, I am very happy with my frankin bike.