Hey, so I am looking to get my buddies yfz 450, Its a 2005 and it runs, but when you get past the 1st quarter throttle or so, it starts blowing smoke and bogs down. It doesn't die, but it has no power. Just wondering if anyone knows what's wrong and if it's a cheap fix or not. I think it may be the jetting on it or possible piston rings are bad and letting oil in to the combustion chamber. Anything helps. Thanks.