Keihin 38mm PWK Air Striker Carb
The KDX top end is originally designed for a 35mm carb, since we want top end grunt we went for a Keihin 38mm PWK Air Striker Carb
A = 46mm, B = 63mm, C = 91mm, D=171.6mm (from Keihin website
One issue that had to be resolved was throttle travel not allowing full throttle, as we now have a carb with a 14mm larger throat that the original PX. This was resolved by trimming back the throttle stop, so the cable travels further.
Another moditifcation is an angled top cable entry point. With the original (below), the cable will hit the side panel.
Jetting Notes
Needle Jet - B(taper) G(L1) N(diameter) : need richer throughout the range
taper richer: C D E ...
To try:
Main Jet - 165 (need richer)
From above - BGN 165... too lean
13/11/2012 - DEL 175...
Links
http://www.carbparts.com/keihin/needles_tuning/pj.htm
http://www.duncanracing.com/TechCenter/KeihinCarbJetting.pdf