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1980 CX500C
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8 Posts
Discussion Starter · #1 ·
Hello all -

I was cleaning the carbs on my 1980 cx500c and the butterfly valves on the throttle side were completely closed. I adjusted the idle knob as far as it could go and the butterfly valves barely budged. And in full throttle, the valves only open about a quarter of the way. Is there a way to adjust this?

Thanks in advance!
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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11,450 Posts
The butterfly valves are normally closed. Check your throttle cable if it's not fully opening. How much free play do you have at the grip? Stock handlebar and throttle cable?
 

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1980 CX500C
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8 Posts
Discussion Starter · #3 ·
The butterfly valves are normally closed. Check your throttle cable if it's not fully opening. How much free play do you have at the grip? Stock handlebar and throttle cable?
carbs are off the bike...sorry forgot to mention that. Maybe this is a non-issue. I was just surprised the valves were hardly open at all (like, not even noticeable) when in idle position
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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11,450 Posts
If the cables aren't connected, they should be completely closed until you rotate the cam where the cable attaches. It should open 90 degrees.
 

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'84 CX650E that is evolving into a GL500
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17,736 Posts
The butterfly will have the least resistance to airflow when it is rotated to where the plate is parallel to the direction of flow. If it opened any more than that it would start to reduce the flow.
 

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1980 CX500C
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8 Posts
Discussion Starter · #6 ·
The butterfly will have the least resistance to airflow when it is rotated to where the plate is parallel to the direction of flow. If it opened any more than that it would start to reduce the flow.
Thank you! My concern was they weren't opening enough and still at a diagonal with the air flow. But I think this is something i won't know for certain until I put them back on the bike and test. Appreciate the help!
 
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