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Guest mxrider426

BK mod jetting

3 posts in this topic

Do you have to richen the bike up after doing the BK mod? If so, how much?

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Not necessarily. The aim of the BK mod is to rid the engine of that annoying hesitation when the throttle is whacked open quickly. It appears that each machine responds differently to this mod. The BK mod, in a nutshell, shortens the duration of the fuel squirt delivered by the acceleration pump. To tune this fuel delivery, begin by adjusting the initial timing so that it just clears the bottom of the slide. It should not hit the slide. Then, it should only squirt for about .3 seconds. Yep, it's just a quick squirt. With an acclerator pump type of carb, this design is meant to deliver fuel quickly that would otherwise be dependent upon intake vacuum as in a CV(Constant Velocity) type of carb.

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This is the jetting that works the best in my 2000: 168 main EKP needle clip 5 42 pilot 1 turn out on fuel screw 92 pump gas 1600 ft elevation Didn't get best results from BK Mod until I raised the needle 1 clip. No bog, no hesitation, pulls strong all the way thru. Specifications subject to change- your results may vary.

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