The best thing to do is search the forum for scrambler 50... you'll get a lot of information that people have already posted.. with that said...
The Scrambler 50s do not usually have a wire to cut... to find out if you do, look above the carb, strapped to the frame with a big rubber band for a box (2x1x3/4 inches or so) with 5 or 6 wires coming out if it. This is your CDI. Pull that box off, and look for a (normally) green wire that comes out of the back of the box (not near the rest of the wires) and loops back in.. cut that wire and tape up the ends.. you're now able to rev wide open... if the box does not ahve that looped wire, buy a CDI off of Ebay that is made for an Eton like this one
http://cgi.ebay.com/ws/eBayISAPI.dll...category=11754. Cut the green wire and install it.
After that, get a pipe and a free breathing air filter (Uni, K&N).. then you'll need to rejet the carb (I'm using a 105main).. from there, work on transmission mods (Clutch, transmission gears, sprockets).
Our quad took a 2nd place win in Moto 2 at this months GMQA races.. a similarly set up quad took 1st in both motos that night.
Look at
APB-Racing.com and
GMQA.com for some video clips with these quads in them.
I've had our quad at 35mph on flat gound with 19T/27T sprockets on it.. there's lots of potential in these little quads.
Bryce