Are jet kits worth the money???

1 reply to this topic
  • 642MX

Posted June 28, 2005 - 04:25 PM


It seems there are a few jet kits on the market for my 426, but are they really worth the $60 they cost? The weather in southern Indiana is very hot and humid, and my bike doesn't start and run like it did when the weather was cooler. Should I bite the bullet and buy a jet kit, or grab a handfull of jets and start the trial and error process?

Does anybody have a jetting recommendation for sea level, 90 degree heat and 70-80% humidity?

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  • ovrrdrive

Posted June 28, 2005 - 05:49 PM


I've seen countless people rave and rave on the JD kit, but honestly, by using the right jets for my bike I don't need or want any more power and really I don't see how it could put out too much more anyways.

If you're a tinkerer and don't mind fiddling with the carb to get it right, buy a handfull of jets and do it yourself.

If you don't like to get your hands greasy, buy a kit and have someone else do the legwork for you.

The biggest part of the JD kit is the custom needle that you can't get anywhere else. The needle is what controls the fuel delievery during 1/4 to 3/4 throttle. If I think about my riding and what throttle position I use the most, I'm either idling through the tight corners or going WOT on the straight sections. I rarely ever even use the needle...

I'm going to say that I doubt a jet kit would do anything for me at all. I say do it yourself. :)

Oh and as for a recommendation...

Get yourself an adjustable fuel screw like a Zipty if you don't already have one and drop back one size on the pilot jet first, and of that doesn't clean it up drop back one on the main as well. By playing with your jetting you will learn what lean and rich feel like, and know what to do to solve them. Once you get it close, daily adjustments on the fuel screw will put it right where you need it.

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