I trust my motor even more with the 904 than I did with the stock motor. I bought mine with 3400 miles and it burned oil and leaked at the head gasket. I installed the 904 at about 11000 miles, now have over 27000 of problem free riding. No leaks, no burning oil. Much power. And I'm the kind of guy that hits the rev limiter all the time and will do the ton almost every time I take the bike out.

Always remember to be yourself. Unless you suck. Then pretend to be someone else.