So your carb was causing the bike to run bad, but you adjusted it now it runs ok but won't start hot, and it was leaking coolant into cylinder causing it to knock but now it doesn't, except at high rpm's....so what I'm hearing is your bikes motor knocks at high rpm and has a hot start problem.well if the knock is mechanical, and you'll find that out soon if the motor blows up, if it doesn't then it's probably ignition timing, causing it to ping, if the motor doesn't blow up, then you can fix the hot restart problem, which I would definitely start with ossagp's advice and check the float level, but also wouldn't be a bad idea to check the compression when the motor is hot.also check for a good coil spark when hot.
