Carb Rebuild: Accel Pump problems

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Carb Rebuild: Accel Pump problems

charlesd89
Hey guys. I'm rebuilding the carbs for my 81 cb750f and ran into an issue with the accel pump. I'm told that when testing the pump there should be a squirt of gas coming out of the brass diffuser. I tried that and nothing came out. The directions I'm using says to "troubleshoot" the problem but I don't know how to do that. Suggestions?
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Re: Carb Rebuild: Accel Pump problems

charlesd89
To bring more clarification to my problem, here are the directions I'm using. The process is on pgs. 26-27: http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revD.pdf
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Re: Carb Rebuild: Accel Pump problems

TOOLS1
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In reply to this post by charlesd89
Either your little ball valves are plugged, or the diffusers are plugged. You need to do more cleaning.
TOOLS
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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
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Re: Carb Rebuild: Accel Pump problems

seestheday
In reply to this post by charlesd89
You can soak it for longer, and if you have a access to an ultrasonic let it sit on it for hours.

If that doesn't work, soak for a bit in carb cleaner, and if that doesn't work you can take it apart. The brass or plastic square plug is pressed in. Behind it is a tiny ball and spring. Make sure you don't lose them if you do take it apart.
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals

My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.

My cb750 video site
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Re: Carb Rebuild: Accel Pump problems

seestheday
Oh, more details on this in the dohc carb cleaning thread on this forum. I believe it was lucky that wrote a detailed post on this specific issue.
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals

My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.

My cb750 video site
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Re: Carb Rebuild: Accel Pump problems

Lucky 1
In reply to this post by charlesd89
Forget about those instructions.
They are not showing enough details.

The bottom plate of the accelerator pump is critical.
If the check ball in the bottom of that plate is corroded with rust and pitting or the sealing surface you must replace that bottom plate and check ball.
There are two of these one way check valves and one is in the top edge of the float bowl.
That one keeps fuel from draining back down into the bottom of the accelerator pump.
Take a small plastic straw and test it. air should only go one direction.

The prass plug or plastic plug can be carefully removed pried out with a miniture screw driver and the spring and ball will come out.
If you roll the steel ball around on a piece sand paper you can clean it.
But look at the ball with a magnifying glass to see if it is pitted.

Test it after it is all put back together.
Look into the intake and (ENGINE OFF) and gas on and see that when you turn the throttle a couple times that gas should squirt out of the brass nozzle sticking up. Check all 4.


On a Roadstar Adventure.
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Re: Carb Rebuild: Accel Pump problems

seestheday
Link to the post Lucky wrote on a different forum with pics: http://forums.sohc4.net/index.php?topic=94278.50

He wrote it for the SOHC, but the accel pump didn't change (the rest of the carbs however - changed completely).
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals

My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.

My cb750 video site
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Re: Carb Rebuild: Accel Pump problems

robs750
In reply to this post by charlesd89
Also make sure the O-Ring is on the float bowl and is the correct one.