Accelerator Pump

how can I tell if my Accelerator Pump is working or not?

It works similar to any automotive accelerator pump. If you whack the throttle open while looking down the throats of the carburetors, you should see a stream of fuel shooting out of the carbs and headed to the intake port.

Good luck, Paul

This pertains to the VM24 carburetors & may be applicable to the bigger carbs.

If yours isn't working right, Z1Enterprises.com sells a K&L accel pump kit (K&L parts are made in Japan & oem quality IMHO).

Note hole in gasket for Accelerator pump nozzle fuel supply (top hole).
Also note the little spring clip. Each carb bowl should have a clip, weight, & ball: the 3 little parts act as a check valve to keep fuel in the pump circuit.


Note o-ring on Accelerator pump nozzle's base. The nozzles project into the carburetor bore.
Check the nozzles by supplying fuel to the carbs, then actuate the throttle pulley vigorously: fuel should squirt out straight back without hitting the carb bore walls. If it dribbles out or squirts crooked, the nozzles or pump circuit may be clogged or the accel pump diaphragm could be defective.