My 2008 Kawasaki KX250F runs bad. It doesn’t want to start and it feels boggy down low. Everyone says that you guys know all the answers about motocross jetting. What should I do?
We changed everything and we mean everything in our 2008 KX250F’s carb. Here are MXA’s recommended 2008 KX250F jetting specs. The stock jetting is in parentheses.
Main: 175 (182 stock)
Pilot: 42 (40 stock)
Needle: NCYS (NCYU stock)
Leak jet: 50 (55 stock)
Clip position: 4th from top (2nd stock)
Fuel screw: 2-1/2 turns out (1-5/8 stock)
Notes: To help starting and the low-to-mid transition, we upped the pilot from a 40 to a 42. To help with starting the KX250F, we also added a $179 Boyesen QuickStart accelerator pump doo-hicky. It uses the hot start lever to close off the accelerator pump orifice. This stops excess fuel from squirting into the engine when it is hot. The QuickStart comes with a tunable leak jet, 25% more fuel capacity and a high-volume check valve for consistent fuel metering. It is a bolt-on. It worked like a charm. For more info go to www.boyesen.com.