ive got a 95 CBR600 F3. Im looking into building up a motor for street/track use. I want something that will have a good powerband forroad racing and still be reliable to last a while. When its all apart i was planning on doing cams, port and pollish, cam gears, new valves, springs, retainers guides, and a 5 angle valve job. What id like to know is if what i have planned already is a good idea, and id like to know some good ideas for the bottom end.

 

It depends on what kind of track use you have planned for it. If you think that you're going to end up racing, you need to get the rule book for your race organization and decide what class you want to race in.

You can go with a Supersport build - the engine will have to remain at, pretty much, stock bore. You can clean up the heads and get a Supersport cam which will have a slightly longer duration for some extra top end.

If you go to a middleweight class build, depending on your organization, you might be able to take the engine up to 636cc by going to a 2mm overbore. At that point you can go to higher compression pistons to recapture some of the lost low-end and midrange from the more aggressive cams. That will require the extra expense of sleeving the engine, but you get more power and more torque - good for those tracks that are considered tight, technical venues.

For the bottom end of the engine, if you go with slightly lighter rods, like Carillo, or a lot lighter rods, like Ti Pankl's, then you can send the rotating mass (crank, rods, pistons, pins, etc) and get the crank lightened and balanced. It won't give you more hp, but it will allow the engine to spin up faster, which will feel like more hp. A cheaper way, for starters, is to go with a total loss electrical system that gets rid of the generator stator. Or you can do both and really spin the engine up quickly.