07 yz450 dirttrack carb mods


5 replies to this topic
  • jmik517

Posted August 05, 2010 - 04:51 PM

#1

I was wondering if anyone had any suggestions on carb mods to help increase mid-range power for dirttrack / iceracing? I have a suppertrapp exhaust system and a k&n air filter. I'm currently running a 50 pilot jet and a 168 main jet. I have a works connection fuel air screw adjustment I do a little tweaking on from time to time to help the rev off idle. Any ideas or suggestions would be appreciated!

  • Ron Hamp

Posted August 08, 2010 - 10:59 AM

#2

the stock carb is small and the bike responds very well to having the carb bored we also installed honda air boots on them also helping .

  • jmik517

Posted August 09, 2010 - 11:01 AM

#3

ron, I've been told that boring the carb without a flowed head, doesn't yeild much gain? And what is the reason that the honda air boot helps?
You've recently sold a head to a friend of mine, Corey Clare, The bike ran great at the Goshen 1/2 mille, he was very happy with the motor.
Thanks

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  • Ron Hamp

Posted August 10, 2010 - 04:44 AM

#4

I belive that tryce and me tryed putting one of my bored carbs on an early 450 yamaha that was stock with a pipe and it was over 2 hp gain.a couple of years ago i ported a head on one bored the carb and put a chm pipe on and the bike went from 46 hp to 54 hp with pump fuel i also installed a 13.5 piston

  • grayracer513

Posted August 10, 2010 - 02:53 PM

#5

I belive that tryce and me tryed putting one of my bored carbs on an early 450 yamaha that was stock with a pipe and it was over 2 hp gain.a couple of years ago i ported a head on one bored the carb and put a chm pipe on and the bike went from 46 hp to 54 hp with pump fuel i also installed a 13.5 piston

With the stock head, was it necessary to open the outside end of the main intake port to match the carb? If so, about how far in would you recommend "blending" it?

  • jmik517

Posted August 10, 2010 - 04:15 PM

#6

what about the james dean jet kit, would it be worth trying in a dirttrack application, or is it designed for just mx racing?





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