300ex motor building ?'s

[mxpimp2000]

I have quite a few questions for building a national leverl 300ex.
I dont have the dollars to send it to TC or i would. My little brother needs some more power desperately. Right now The mods are bigger carb/sparks exhaust/port n polish/bigger valves/cp piston/k&n filter no lid/webcam. Im wanting to know about making this bike rev alot faster and pull alot longer in the gears and have the power to pull longer. I know chainging the sprockets will change the gearing but just because we gear it taller dosent mean it will have the power to pull hills. Right now hes having problems with the rev limiter and we already went down on the rear sprocket but cant go bigger on the front because we want to run the case saver.

Will shaving the flywheel help much?

should we cut the air box down?

what kinda intake mods can we do?



This bike dosent seem fast at all and unless this local shop screwed us over with all the motor work we paid for then idk why its not as fast as it should be.

[838xcracer]

We run a Curtis sparks no rev cdi it will take care of the cdi problem. The intake was also ported and polished. What cam u running. We run a web stage 3 with 2mm over Kibble White valves and springs. What compression ratio piston are you using. We run a 12:1. Also for about 600 bucks webcam will stroke your crank.And that really helped. On the gearing we run stock gearing.This quad has a ton of torque and pulls like a train. It will holeshot piped z400's and 400ex's.

[838xcracer]

I don't understand what cutting the airbox will do for the engine. Here is the lid I made for his. It works great. Also I wouild get rid of the K&N filter. They let in to much dirt and are hard on the engine.Run a uni a much better filter. And cutting the flywheel does help,it will let it rev quicker, but it is alot harder to keep it running. It is easy to stull that way and harder to ride in the woods.

[mxpimp2000]

this is for motocross so woods riding isnt a problem