2003 WR450F Accelerator Pump Weak Stream.

I've been thru all the steps/mods of the bog issue and still have a weak stream out of the AP nozzle... I've done the o-ring mod put in a new diaphram and cleaned all the jets etc. I noticed there is fuel coming out this hole when the AP pump is triggered I just need to know if that is some sort of overflow (or normal)?... I thought it might be why the stream is weak, losing pressure here? Thanks for the help I'm a nooby with this style of carb but am not mechanically challenged just bear with me. THANKS IN ADVANCE!

1397334267184.jpg

You need to service the apump system

Clean the apump passages, and make sure the check ball-bearing is not stuck

       - better yet, upgrade to the 2008 crf450r version: there is a kit for this on crf'sonly.com

Diaphragm: must be pilable and have the short rivet

No corrosion anywhere

Leak jet: must have 50 or smaller to get a properly filled up cavity

Linkage spring: if it is stock, it will never squirt right. You need to wire it shut (mickey mouse version) or better yet replace the spring with a merge racing or tokyo mods spring.

You might also soak the brass nozzle in some solvent: I used a little cap over the nozzle and squirted PB blaster underneath. You can also try a piece of wire from a wound guitar string.

Looking at the picture again, you are showing squirt with the slide down.

That is not right.

I think you nozzle is clogged and it's having a hard time 'emptying' the apump reservoir. 

I'm positive all the AP passages are clean and clear. I really cant afford to buy an upgrade. I have considered grinding down the long rivet on the diaphram but wanted to see why the fuel was coming from that specific hole, or (if that was normal)? I can troubleshoot from there.

Oh and as for the timing with the slide down. I dont have the throttle cable hooked up so I just manually pushed the AP lever and it is both a short and weak stream.

Inspect/test the check valve in the float bowl.

 

You cannot fully operate the AP how you did. Rotate the throttle wheel quickly.

You need to service the apump system

Clean the apump passages, and make sure the check ball-bearing is not stuck

       - better yet, upgrade to the 2008 crf450r version: there is a kit for this on crf'sonly.com

Diaphragm: must be pilable and have the short rivet

No corrosion anywhere

Leak jet: must have 50 or smaller to get a properly filled up cavity

Linkage spring: if it is stock, it will never squirt right. You need to wire it shut (mickey mouse version) or better yet replace the spring with a merge racing or tokyo mods spring.

You might also soak the brass nozzle in some solvent: I used a little cap over the nozzle and squirted PB blaster underneath. You can also try a piece of wire from a wound guitar string.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now