how to adjust accelerator pump?

If it's broken or just needs tweaked

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juntjoo
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Joined: Fri Nov 10, 2017 6:19 pm

how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 6:20 am

https://youtu.be/bvjx9-uleYY

as I state in the vid, two guides I've read simply state to bend the adjusting arm. Are we talking about taking it out and putting it in a vise and getting out some tools or use some pliars and bend a little something in there? and why didn't they just make it adjustable with a knob or something
82" cb650 Nighthawk

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Folsoml
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Re: how to adjust accelerator pump?

Postby Folsoml » Wed Jan 17, 2018 6:42 am

The accelerator pump works by works by allowing fuel into a chamber and then, when you turn the throttle, it pushes that fuel out and spritzes it into the carb bank--giving a temporary burst of fuel when accelerating. You mentioned that you were concerned that the condition of yours, being partially compressed, might be allowing too much fuel in. Quite the opposite actually. It you picture squeezing water out of a sponge, this is kind of how it works. If you squeeze the sponge, but only release it half way, it is not going to have as much water for the next squeeze as it would if you released it all the way. The pump does not work like a valve, where if it is partially opened, fuel will continue to flow through it.

That being said, the accelerator pump rod is cheap, readily available, and easy to replace; whereas the actuator arm on the carb can be expensive, hard to find, and a pain in the ass to try to replace. If it was me, I would take a grinding wheel and shave off that tiny portion of the end of the pump arm until it fits like it should.
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juntjoo
Posts: 182
Joined: Fri Nov 10, 2017 6:19 pm

Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 7:39 am

Folsoml wrote:The accelerator pump works by works by allowing fuel into a chamber and then, when you turn the throttle, it pushes that fuel out and spritzes it into the carb bank--giving a temporary burst of fuel when accelerating. You mentioned that you were concerned that the condition of yours, being partially compressed, might be allowing too much fuel in. Quite the opposite actually. It you picture squeezing water out of a sponge, this is kind of how it works. If you squeeze the sponge, but only release it half way, it is not going to have as much water for the next squeeze as it would if you released it all the way. The pump does not work like a valve, where if it is partially opened, fuel will continue to flow through it.

That being said, the accelerator pump rod is cheap, readily available, and easy to replace; whereas the actuator arm on the carb can be expensive, hard to find, and a pain in the ass to try to replace. If it was me, I would take a grinding wheel and shave off that tiny portion of the end of the pump arm until it fits like it should.


thanks. I was thinking the same about cutting it. I confused how it got this way though. it wasn't before I took it apart. I'll keep tinkering with it to see what I may have done
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GeorgeSweety
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Re: how to adjust accelerator pump?

Postby GeorgeSweety » Wed Jan 17, 2018 11:53 am

juntjoo wrote:thanks. I was thinking the same about cutting it. I confused how it got this way though. it wasn't before I took it apart. I'll keep tinkering with it to see what I may have done


Definitely tinker, as it should fit now if it did before.

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Folsoml
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Re: how to adjust accelerator pump?

Postby Folsoml » Wed Jan 17, 2018 1:18 pm

Twist the black throttle adjustment knob back out and see if that releases the pressure.
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juntjoo
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Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 1:31 pm

does anyone know what the spec is on the length of this rod? thay would tell me definitely if I need a new one
82" cb650 Nighthawk

juntjoo
Posts: 182
Joined: Fri Nov 10, 2017 6:19 pm

Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 1:36 pm

Folsoml wrote:Twist the black throttle adjustment knob back out and see if that releases the pressure.


well it would have to be a good 2 millimeters and it would throw the #2 choke off right?
82" cb650 Nighthawk

juntjoo
Posts: 182
Joined: Fri Nov 10, 2017 6:19 pm

Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 1:53 pm

or, can anyone get me the relationships between the rod, the adjusting arm, and the carb body in the back there. with the length of... my rod, it wants to go all the way but still leaving room for the adjusting arm. the way it's currently adjusted, we have like 3mm behind the adjusting arm to the carb body. it's in the middle of the pic:

https://imgur.com/a/L5DYo
82" cb650 Nighthawk

juntjoo
Posts: 182
Joined: Fri Nov 10, 2017 6:19 pm

Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 2:48 pm

I'm wondering if I may have put weight in the arm with the spring that links the throttle pulley to it all and bent it. Mine's 90°. Im wondering if it WAS like 95°

https://imgur.com/a/CaXkd

can anyone check the angle on that arm for me?
82" cb650 Nighthawk

juntjoo
Posts: 182
Joined: Fri Nov 10, 2017 6:19 pm

Re: how to adjust accelerator pump?

Postby juntjoo » Wed Jan 17, 2018 6:15 pm

F it. I just cut off 3 millimeters and it's perfect. hopefully no one responds telling me I messed up
82" cb650 Nighthawk


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