Re: water in the cdi and clutch wear issues
i change out the plug wire for a better one (7mm copper core, non-resistance) and slide a piece of heat shrink tubing over it when i install it. it's just screwed into the CDI, so you can unscrew it to take it out.
when i'm wiring up a bike, i take out the rubber grommet at the magneto, slide another piece of heatshrink over the white cloth bundle all the way up to the mag, then put the grommet back in. makes it look cleaner, too, not having the wires showing.
another old moto-x trick is to get a rubber boot and put it over the throttle cable and the top of the carb so water can't trickle down into your carb.
my advice, is make sure a part is bad before you replace it. i wish i had all the CDI's and Magnetos that people keep replacing for no reason, then i could sell them back to them when they think the next one went bad.