Dynojet kit

I just received my dynojet kit and it does not contain a 5/32 inch drill bit nor does it make any mention of drilling the slide. Contains the new spring, washer, circlip, needle and 2 jets, 160 and 165. Should I drill the slide?

Use the search function, there are about a millon posts on this.

Most say the DJ kit sucks and you are better off not using it. I bought the DJ kit and it wasn't any better than stock.

Get a 58 pilot and a 158 main, shim the needle, and drill the slide. Night and day difference.

But it still is the stock carb, Edelbrock is the way to go.


there's nothing wrong with a DynaJet kit, except that it's way over-priced ... the idea of drilling the slide is to make the throttle more responsive (the weaker spring supplied with your kit does the same thing) ... the unusually shaped needle does the job of a larger low-speed jet ... I installed the weaker spring, and drilled the slide also .. works perfectly ... and my DynaJet mods made a significant improvement to my XR650L ... go with the larger mainjet, if you are running an aftermaket exhaust ... also, be aware when you see different-sized mainjets mentioned in posts, the DynaJet and Keihin jet sizes are different ... a 165 DJ is same as a Keihin 158, IF I remember right ... :applause:

The weaker spring doesn't make as much difference as drilling the slide.

The weaker spring MAY at steady-state (I'm coming to realize) open the slide more for a given throttle setting.


I just installed the Dynojet kit on my 03 650L and what a difference, maybe not perfect but a great improvement, the motor is stock and I have a Supertrapp Ids2 exhaust and a Uni filter so I went with the 165 jet and the new spring and needle, but no drilling of the slide. The bike is much smoother and has not yet died at idle like it was, also before the jet kit the bike seemed to take a long time to warm up I would keep the choke on for a long time now I just need the choke for starting and I shut it off within a block of driving it. I was ready to change the carb but the bike is much more drivable now and until I make some motor mods I think the DJ kit is a great improvement over stock. :thumbsup: And now the front tire really wants to come up in first gear :bonk:

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