acceleration pump of Keihin

I have been thinking about disabling the acceleration pump to see if I can get better fuel economy. How would this effect performance and how would I go about disabling the pump?

Bill

if you have the early carb you should do the taff mod. to disable this all you need do is remove the diaphram from the chamber below tha carb. if you have the later mark 2 carb which has the pronounced downdraught, you will do the BK mod. with this you simply turn the screw in until there is no movement whatsoever. it isn't rocket science.

the desired squirt is recommended by myself as as short as the function of the pump will allow so that it can re-fill and not fluff and fart. on the mark one i set it by doing the taff mod and then making the gap to the model clamp = .24" or .6mm with the old feeler gauges.

same goes for the mark 2. minimum to work.

some people delay the start until the slide is up. this is wrong.

1) the downdraught of the air sends the fuel spray uinderneath
2) if it did hit the slide and smash the fuel into atoms we'd all be happy
3) the APJ is only wanted off a closed throttle and NEVER anywhere else

hope this helps.

look forward to you reporting back after back-to-back tests!

regards

Taffy

Got a `04 FE450 and I did look at the adjustment screw and turned it in a couple of turns, didn`t notice much differance. So next step turn screw right home. It will be xmas time before next out so I will report back then.

Bill