Honda PA50I or PA50M Performance (or lack thereof - and what you can (or can't) do about it)

From MopedWiki

Before you start the process of tuning your PA50I, you should consider the pros and cons. In the Honda PA50 section of the Wiki, the differences between a PA50I and a PA50II are listed. This list is longer than you think!

In summary though, here's my own two cents:

If you are going to "kit" your moped, meaning you are going to buy a cylinder and exhaust, it may not matter which motor you start with. The reason: the crank and block are essentially the same. The differences (motor wise) then boil down to the carb, reed, manifold, ramp plate and rollers. I bought a new ramp plate and new rollers from Honda. That leaves the carb, reed and manifold. If you can buy these three items for the price of a motor, or close to it, then I'd go for it! If you can't, then you decide.

NOTE: The PA50II variator will not "bolt-on" to a PA50I crank (the outer bearing has a different inside diameter). A PA50II ramp plate can be put on a PA50I variator - if the variator is modified first. Go here for more info: PA50I variator using PA50II ramp plate

If you are not going to "kit" your moped, then I'd say that you are clearly better off buying a PA50II motor, that is complete, including the variator, carb, etc. You'll be better off (assuming that the compression is good on the motor you get).