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Author Topic: cb550 low idle on start  (Read 1703 times)

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Offline jonclegg

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cb550 low idle on start
« on: September 18, 2012, 04:33:34 PM »
I have a 78' cb550. 9k original miles. It starts right up when cold, but it then idles really low, maybe 700 with the choke fully up. Is that normal, or should I adjust something?
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Offline TravisB

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Re: cb550 low idle on start
« Reply #1 on: September 18, 2012, 04:40:32 PM »
Mine does this too.  After about 2 or 3 blocks it warms up and the idle evens out.  If I put the choke down after about 5-10 seconds the idle will come up.
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Offline TwoTired

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Re: cb550 low idle on start
« Reply #2 on: September 18, 2012, 04:42:42 PM »
The 78 should have a choke knob and PD carbs.  There is a fast idle cam and a screw adjust for it.  Adjustment is described in Chapter 19 of the Honda shop manual.

Fast choke idle speed is 3000-4000 RPM
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline jonclegg

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Re: cb550 low idle on start
« Reply #3 on: September 18, 2012, 05:18:06 PM »
Is the "fast idle" adjustment different then the normal idle adjustment screw? If I adjust the normal idle screw it'll jus idle too fast once it's warm.
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Offline TwoTired

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Re: cb550 low idle on start
« Reply #4 on: September 18, 2012, 05:59:06 PM »
Quote from: jonclegg on September 18, 2012, 05:18:06 PM
Is the "fast idle" adjustment different then the normal idle adjustment screw?

Yes.

Fairly well explained in the Honda Shop Manual chapter 19.
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline killersoundz

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Re: cb550 low idle on start
« Reply #5 on: September 18, 2012, 06:38:15 PM »
I don't know about any of this fast idle screw witchcraftery, I just keep tweaking my idle screw until my bike warms up. it's a 750 though the idle screw is easy to get to on the left. heck I'm tweaking it at every other stop light.


even used it as cruise control on a long highway ride  8)
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Offline bjbuchanan

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Re: cb550 low idle on start
« Reply #6 on: September 18, 2012, 06:52:09 PM »
Quote from: killersoundz on September 18, 2012, 06:38:15 PM

 heck I'm tweaking it at every other stop light.



that's what she said
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The dirty girl-1976 cb750k, Ebay 836, Tracy bodykit
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