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1982 CX500C (US)
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Discussion Starter · #1 ·
So I’m still getting a small misfire (firing back out the intake, not a pop) at stop lights on the right side after I’ve been driving for a bit.

Everything is perfect at idle, and if I feather the throttle for about 10-15 seconds for it to recover it’s good again.

I’ll need to verify the fuel level with a hose on that carb, but I was thinking of buying some new adjustable floats as I have the plastic non-adjustable ones. (At least not easily adjustable)


Would a low fuel level in the bowl cause something like this? 82 CX500C with the T-style fuel feed so when upright both carbs should be equal opportunity to get fuel when not on the side stand.

It’s totally rideable but a bit of a final annoyance I’d love to sort out!
 

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I have an '82 cx500, and I am having the same problem. I'm not sure, but I was going to check plugs and cables first. I only take out the carb if I must.
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #3 ·
Yeah I’ve had the carbs apart tons of times, and it works great at regular idle forever, it only happens to me after riding for a bit and then returning to idle like I said.

I’m considering ordering some adjustable floats as I mentioned but don’t want to if I don’t need them.
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #5 ·
On the side stand with a block under it for near level, running, drain open.

top blue mark is about where it goes if I make the bike completely level (I don’t have a center stand or Jack)

right carb.
8BD3AF55-B7BC-4C03-A3C8-EC600D781C92.jpeg
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #7 ·
The upper line is perfect.
Well that’s unfortunate! I’ll check the left one too,90% sure it’s the right one that’s misfiring though.

what are some other possible causes if not the float level?
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #9 ·
Small vacuum leaks maybe.
Boots are mint and sealed well, no leaks I can find in the driveway. It only happens after I’ve been riding for a bit and come to a stop, then it’s 10-15 seconds of feathering the throttle to keep it happy and then it settles again. Super odd.
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #11 · (Edited)
O rings correctly seated? Have you tried tightening the clamps while at engine temp to see if they take up more?
Orings on the intake headers? I can certainly try that. It’s just funny that it’s not a “while hot” situation but an”after riding” as it settles down after a few seconds.

Used OEM o-rings too ($$ - $12CDN each) but I’ll try tightening them when it’s warm and doing a carb cleaner spray check for a vacuum leak which I have done a few times.

I appreciate the suggestions!

pics from install, new ones on top.
208348

208349
 

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1982 CX500C (US)
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175 Posts
Discussion Starter · #14 ·
Here’s my other thread where I talked about the o-rings in a little more detail. The old ones were thick, gooped, etc.

.

The new OEM rings do clear the flange, but not by much and certainly don’t fill the space in the same way.

But again in the driveway I don’t think I have any vacuum leak from carb cleaner spray tests and the misfires don’t happen there although I’ll try some extended revs and see if I can recreate the problem without riding.
 
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