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Mike's CB550 Project
Mike_Berkshire:
--- Quote from: DomP on March 16, 2025, 08:18:31 AM ---So is that why I have a hanging idle yet also symptoms of running rich like sooty plugs and strong fuel smell? Sounding like another carb off job
--- End quote ---
I have exact same symptoms Dom
McCabe-Thiele (Ted):
To save me trawling right through this thread are you both running on 087A carbs?
Is there any sign of wear on the main jets or needles?
Needles in the middle position(3).
My 069A carbs had needles with no middle poistion, all changed to original needles & jets courtesy of Ken.
Oddjob:
069a carbs are for a CB550F not a CB500K Ted, as I'm sure you know. a 500K made for the UK should be wearing 627B carbs. The 069a carbs have 4 slots on their needles and it runs at 2nd from top as standard IIRC, the problems here sound like flooding to me, if you can smell petrol there's something wrong. Flooding will cause it to run really rich, hence the black plugs, it's like the engine is running on fast idle setting on a car with auto choke.
As these bikes get older we don't know what's been done to them before we bought it, it may no longer have the same brassware it was made with, a lot of people tended to think they'd be better replacing it with stuff like Keysters etc thinking it was wearing etc, worst thing they could have done IMO. The next owner then has to suffer that mistake and a lot move the bike on because it's not running as it should and they don't know why.
DomP:
Mines an F Ken on 069a carbs with all original jets etc (some bits supplied by you to replace damaged items) I've adjusted the floats to the specified 21mm? from memory, it will definitely start happily with no choke whatsoever even in cooler weather.
McCabe-Thiele (Ted):
What needles & Jets are fitted to your 550F Dom?
Something sounds wrong if it starts without choke.
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