All lights are changing intensity when you rev the engine?
(headlight, as well as the tach/speedo light?)
Are you having to jump start the bike to get it running?
Do you have a multimeter, or some way to read the voltage at the battery with the bike running?
(They're like $4 at Harbor Freight.)
There could be a loose connection at the battery terminals, bad cable...bad battery....bad ground......alternator sucks...voltage regulator sucks, etc.
Luckily, you can eliminate most of this crap by trouble shooting a bit....
Hey, you found the screwed up wire. You'll figure out this, better yet, let MR RATBIKE learn the intricacies of his new bike!