JD jetting and the two O-ring's ???

First thing I did was do a search and I couldn't find anything on the two o-rings that come with the JD jet kit. Used Indy's recipe chart and for my elevation (0 to 4000 feet and 60 to 75 degrees) I put in the 168 main. JD red #5, 48 pilot, 1.5 turns on the Zipty, 65 starter jet (gotta order up the 70) and a #50 leak jet (gotta order up the 40) Did the instructions in the JD kit word for word but there were two points that were kinda fuzzy....one was checking for the 2mm space on the pump and the two o-rings. Some help would be GREATLY appreciated

thanks guys :thumbsup:


Its amazing what you can find when you use the search function and its not 2:30 in the morning :thumbsup:

The two o-rings are for the accelerator pump and they increase the hit the carb makes. The small one a medium hit and the large one a pretty big hit. I think this is the large o-ring installed from JD's website: http://www.pbase.com/jdjetting1/image/57130413

Still studying on how this carb exactly works but with the huge wealth of info on this site it helps a lot.

I need to find out how to measure the AP clearance that JD recommends (2.5mm)


Man I got screwed! I didn't get the two o-rings in my jd kit.

You might have a different carb. From your sig you have a 426 right...shoot an email to JD and see if you can even do the mod for that carb. I'm still tinkering with mine but man what a difference from stock. Friggin front wheel can't stay down. Got an initial stutter that will probably clear up with the 70 starter jet and 40 leak.


Oh ok, what bike do you have? You never specified in your posts

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