'77 550 roaming idle, sounds like it's missing

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i'm thinking of buying a '77 CB550F, and it runs okay except sometimes it starts to die when i give it gas, then it'll completely stall. it'll restart fine and after a while it'll run fine again. the other thing is that when it's idling, every once in a while it'll kick air and gas out of one carb, and when i'm cruising on it, it feels like it's hitching along a little. also, the idle constantly creeps up. it'll go up to 3k RPM, and i'll set it back down to 1k. a couple minutes later it'll be back up to 3k. is the timing off, or do the carbs need to be tuned, or is it possibly a spark problem?

-- Amanda Itnyre (myrphy8@hotmail.com), March 23, 2002


Sorry, no answer, but I'd be interested to hear what someone who knows what this is has to say. My '76 550K does a very similar thing, and I'm starting to think it's a combination of things: misadjusted choke butterflies, clogged idle jets, failing/failed points capacitors, failing coil(s), bad wires... the list goes on and on. It needs some serious TLC, but with an '82 CX500 and a '79 CM400T already on the bench, I don't need more parts roaming around! Nick

-- Nick Lenarz (n9viw@yahoo.com), July 12, 2002.


I recently did a little more work on my CB550. After bringing the jet needles back to stock (center) position, it was popping and backfiring into the carbs. I found out that the points were badly pitted, I think because the condensers (what I called points capacitors above) are failing.

I ordered new points and condensers from http://www.crc2onlinecatalog.com, the Cycle Recyclers. They should be in sometime this week. Just cleaning and regapping the points made a huge difference for me, as it doesn't pop or backfire anymore, but the idle still floats a tad, even though it's much more steady.

Drain a little gas out of each carb and check it for sediment or debris. It could be that you're getting some intermittent jet or passage blocking that hitches up the flow of gas into the cylinders.


-- Nick Lenarz (n9viw@yahoo.com), September 16, 2002.

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