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Author Topic: Cb550 high idle  (Read 2927 times)

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Offline Deltarider

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Re: Cb550 high idle
« Reply #25 on: November 15, 2018, 12:19:01 PM »
Quote from: terrorshark on November 15, 2018, 11:44:32 AM
Needle is in center position.
Main jets are #85
Pilot jets #48
Enricher screw is backed out 2 turns.
Not sure what type of PD carbs they are.
Terrorshark, the position of the PD carbnumber is shown in the pics below. Also I added a scheme that lists the jetting of various carbs (specs.html). I must underline that I usually refrain from reposting data that I don't know the source of, in other words: I cannot stand for the integrity. I make an exception here, maybe it can help you.
« Last Edit: November 15, 2018, 12:43:41 PM by Deltarider »
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Offline TwoTired

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Re: Cb550 high idle
« Reply #26 on: November 15, 2018, 08:54:09 PM »
I suggest you raise the slide needle one notch.
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Offline BomberMann650

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Re: Cb550 high idle
« Reply #27 on: November 18, 2018, 07:33:48 PM »
Two Tired and StringBean both brought up the timing advancer.

I'd +1 that. 

Easy to confirm with a timing light.
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Offline terrorshark

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Re: Cb550 high idle
« Reply #28 on: November 28, 2018, 12:42:56 PM »
Advance is perfect. Hitting advance marks when running a timing light.
Checked for air leaks. None.

Still hanging up in idle. Above 3k will hang at around 3-3.5k. Above 5k. Will hang and slowly drop to 4K. Hang. Then drop to 2.5.

Plugs are reading rich. Fairly sooty.
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Offline flybox1

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Re: Cb550 high idle
« Reply #29 on: November 28, 2018, 02:25:34 PM »
at what throttle position are they running rich?
if they are sooty just from general riding...it does not tell you WHAT fuel supply circuit needs adjustment.

Start with an idle plug chop with new plugs, and adjust IMS based on your results.
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Offline uksparky

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Re: Cb550 high idle
« Reply #30 on: November 28, 2018, 02:54:52 PM »
Messing around with the jets can cause this problem....if the carbs are PD46s then they should be 90 main ..pilot 42....here my guess..on the highway the main jet does its thing...coming down to idle pilot jet takes over.....i could be wrong guys but...coming down to idle the main jet is still feeding the fuel flow....not the pilot???...eg wrong jet size....or blockage pilot jets..how about past the pilot jets could be blockage there...
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