Accel Pump

Need a little help on locating my accelerator pump on carb. Still waiting for my sevice manual to arrive. Heard this needs cleaning/checked often. Does this take much time?

Tige Lamb,

Hope this helps.

If the pic isnt too clear let me know and I will e-mail you the original. It looks better.



Darin from Missouri - 1999 WR 400F

Enduro Heaven

[This message has been edited by milkman2544 (edited 04-03-2001).]

Weird. Ofoto is not allowing their photo service to be used like it used to.

Send me your address Tige Lamb and I will send a good clear pic of what your aming at.


Darin from Missouri - 1999 WR 400F

Enduro Heaven

Thanks for the info Hick! Might have to tear into Blue tonight. Darin in heaven, pic will greatly be appreciated. BTW 99WR not as hot as Darins vintage yellow fellow.

MilkMann 2544 While I was writting a response your Pic came to life and its a winner in my book. This helps confirm my thoughts and brings hicks remarks to life. Thanks!!! ThumperHeads and ThumperTalk. Happy Thumpin............

Alright. Good deal. Im glad it worked.

Although Im not sure why the picture came up for you but not for me. Weird. Glad to help.


Darin from Missouri - 1999 WR 400F

Enduro Heaven

What year is your bike? The carb changed for ’00 and the pump linkage is different.

The area above the diaphragm will collect dirt and water that runs down the actuator rod when you wash your bike, sometimes the rod will also bind in its housing.

If you want to clean/check the pump for dirt drain the carb and remove the three little allen head fasteners on the bottom of the carb bowl, they hold a round and/or dish-shaped cup onto the bottom of the float bowl, the pump diaphragm is inside here (You don’t need to remove the large plug or main jet cover to drain the fuel bowl, there is a small, chrome allen-head bolt that, when loosened, will allow the bowl to drain out the lower-most vent hose; make sure you turn off your pet cock first).

Be careful, there are two tiny, tiny o-rings between the cup (or pump housing) and carb bowl, they are not the same size so note what, where, etc. and don’t drop them. Also inside the housing is a soft, short spring that sits under the diaphragm. To clarify, from the bottom of the carb up it goes housing, spring, diaphragm; the two o-rings sit on the edge of the housing in the fuel passages.

With the pump housing off you can squirt carb cleaner into the AP circuit.

Before you put the housing back on you may want to open the slide and operate the linkage/rod with your finger to check for smoooooth operation. If it is binding you will prob. need to remove the rod to clean it and the passage in the carb body that houses it. This is where the instructions will diverge from flat to slant.

If you need to know how to remove the rod or linkage reply with model year.

Hope this helps.

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