Vacuum routing

If it's broken or just needs tweaked

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sprygurr
Posts: 5
Joined: Mon Dec 04, 2017 4:57 pm

Vacuum routing

Postby sprygurr » Tue Dec 05, 2017 6:02 pm

Looking for the answer to where the vacuum line from the accelerator pump ties in on my '81 CB650C.

I've not been able to find a service manual for this year on the site, if anyone can plug me in, many thanks.
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Folsoml
Posts: 1394
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Vacuum routing

Postby Folsoml » Tue Dec 05, 2017 6:54 pm

Welcome to the forum!

I do not understand what you are asking. There is no vacuum or any other kind of line that comes from the accelerator pump. Perhaps you mean the fuel shutoff? In the image below, the red arrow points to the fuel shutoff and the green arrow points to the accelerator pump (these ugly carbs are not mine, but are just a picture I pulled off the internet).

Image

If it is the fuel shutoff you are speaking of, the vacuum line connects to a brass nipple on carb 2 or 3. In the picture of the much nicer carbs below (which are mine :D ), the red arrow points to the nipple.

Image
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

sprygurr
Posts: 5
Joined: Mon Dec 04, 2017 4:57 pm

Re: Vacuum routing

Postby sprygurr » Tue Dec 05, 2017 7:26 pm

I must mean the fuel shutoff. The line that attaches to the nipple shown is what I need help with.
My compliments to the very shiny set of carbs.
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GeorgeSweety
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Location: UK.

Re: Vacuum routing

Postby GeorgeSweety » Wed Dec 06, 2017 3:06 am

sprygurr wrote:My compliments to the very shiny set of carbs.


I wouldn't expect anything less from Folsoml :lol:

cb650
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Re: Vacuum routing

Postby cb650 » Wed Dec 06, 2017 6:25 am

That one just vent to nothing. A hose hangs down to the drain tubes area.



In another note maybe Folsoml is willing to separate and clean a set of my carbs?
Did you clean the tank out?!?!?!?!

sprygurr
Posts: 5
Joined: Mon Dec 04, 2017 4:57 pm

Re: Vacuum routing

Postby sprygurr » Wed Dec 06, 2017 10:28 am

Great, thank you. :!:
I thought this might be the fuel starvation problem. Other posts suggest filling the bowls, which I drained and thought would fill on their own by stroking the throttle.
I had the carbs worked over by a professional and using a clean tank, it should be ready to run. How do I manually fill the bowls with fuel? :?:

Also thanks for the kind welcome, I appreciate this resource.

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Folsoml
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Location: North Florida

Re: Vacuum routing

Postby Folsoml » Wed Dec 06, 2017 11:35 am

You can completely remove the fuel shut off. It's only purpose is to keep the bowls from overflowing if one of the float needles sticks open. If will have to turn the petcock off when you park it. I've removed them on every bike I've had. Just run the fuel line straight from the petcock to the brass fuel intake between carbs 1 and 2.
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

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Folsoml
Posts: 1394
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Vacuum routing

Postby Folsoml » Wed Dec 06, 2017 11:43 am

Here is a set I am most proud of. :D I bought them off ebay for next to nothing because they came off a fire damaged bike. Replaced a few parts and cleaned them up ultrasonically, and by soda blasting them. Good as new!

Image
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,


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