snootfull

Hello, I could use a little help please. My bike seems to "miss" at high rpm and has done so since the day I boght it brand new. It is an '04 TTR 225. At first, I thought that it had something to do with the break in but it is long past that and has been tuned up but is still having the problem. A friend of a friend had the same bike with the same problem (since day one) and he solved it by clipping the wire for the rev limiter. Does anyone know anything about this and if so what color is the wire for the rev limiter??? Any help would be greatly appreciated.