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1980 CX500D
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Discussion Starter · #1 ·
Hi All-

Tried to start my bike with fresh gas after never having it running. No go.

Compression is about 160 each cylinder cold, and spark is good, Rinsed out the tank. So now I am removing and going to overhaul the carbs. The bike came with a second set. It is a 1980 CX Deluxe. The carb numbers are VB 36A OH which was mounted to the bike (no accelerator pump). The second set with accelerator pump has a number VB 28B R1. Not sure which set is the original (if any), although I read that the 80' had the accelerator pump. I downloaded a shop and parts manual but can't find anything there unless I overlooked a page?

Just want to mount the correct set with new seals. Any help would be appreciated.
Cheers
 

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According to my Haynes the VB28 (VB28A-B) are correct for your bike. I do not know what the difference is between a B-R1 and an A-B version.
 

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Discussion Starter · #3 ·
According to my Haynes the VB28 (VB28A-B) are correct for your bike. I do not know what the difference is between a B-R1 and an A-B version.
Thanks Mike, I thought as much. Going to order the parts now- will remove the wood screws previous owner used to hold one of the bowls on. Yikes!

Cheers
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Not sure which set is the original (if any), although I read that the 80' had the accelerator pump. I downloaded a shop and parts manual but can't find anything there unless I overlooked a page?
Look at the spec page in the 1980 Addendum at the back of the Factory Service Manual.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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According to my Haynes the VB28 (VB28A-B) are correct for your bike. I do not know what the difference is between a B-R1 and an A-B version.
The 1980 Deluxe has VB28A (p. 23-3 or 23-7 in the FSM.) Page 24-7 shows VB28B as a variant for the 1981 Deluxe. I don't know what the differences will be.
Any carb from a CX500 Standard or Custom will also fit your Deluxe, though the fuel line routing is different on the Custom.
 

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Your bike will go better with the VB36 as it has a larger venturi than the pump equipped VB28.

Depends how much time you spend at WOT where this actually matters I guess.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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I can't find the VB36 in the FSM. Is it from a non-North American variant? VB26A is on the '78 CX500.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Depends how much time you spend at WOT where this actually matters I guess.
Just long enough to increase the airflow to draw some fuel into the venturi.
 

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VB36 is what was fitted to all Australian twin shock CXs as we never got the accel pump models.

The accel pump is fitted to compensate for the decrease in venturi size.

My 500C was noticably 'gentler' in operation when fitted with the D models VB28s which are now fitted to the Ozdeluxe. There's more power to be had from the VB36s.
 

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Discussion Starter · #11 ·
VB36 is what was fitted to all Australian twin shock CXs as we never got the accel pump models.

The accel pump is fitted to compensate for the decrease in venturi size.

My 500C was noticably 'gentler' in operation when fitted with the D models VB28s which are now fitted to the Ozdeluxe. There's more power to be had from the VB36s.
The 28B variant is shown as an 81 Canadian equipped. My bike was manufactured 9/79, and says 80' on the I.D. sticker. Funny how an Australian carb set ended up here. The only thing I can be sure of on this bike is what is stamped on it. I may just go with the 36 for a little extra power - a little extra is always good when needed!
 

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I'm not sure on this but the US 78 may have been fitted with the VB36s. A US member could tell you better. We just kept getting the same carb through to 82 though later ones fitted with screw in idle jets rather than the early pressed in.

The 78 manual shows no pump but I'm only ASSuming that the pic is correct for the US market.

 

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1980 CX500D
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Discussion Starter · #13 ·
I'm not sure on this but the US 78 may have been fitted with the VB36s. A US member could tell you better. We just kept getting the same carb through to 82 though later ones fitted with screw in idle jets rather than the early pressed in.

The 78 manual shows no pump but I'm only ASSuming that the pic is correct for the US market.

I will go with the 36 and have the 28 for a back-up and spare parts. I just finished my 76 Bonneville which was in worse shape than this one, and arguably worse to work on (underslung rear brake caliper etc.) so its nice to be able to easily get at things.
 

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I'm not sure on this but the US 78 may have been fitted with the VB36s.
VB26, according to the FSM. I'll have a look at the Grub next time I'm in the garage.
 
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