SOHC.co.uk Forums > CB500/550
idle jet differences , 069's
fogrider:
I've seen a few references to it on these forums which makes it appear as a known issue.
It does not bog down when it gets hot, it bogs badly from cold , choke eases it ( then gets too rich and I have to take choke off so it bogs again. ). Perhaps I explained that badly.
Get above 1/3 throttle even when cold and it flies. Runs much better once warmed through , but it takes a few miles. All brass wear is good, new float valves and main jets plus all O rings. No leaks. Fuel levels proved correct.
I've decide to fit my lambda sensor kit tomorrow, just after the 4 into 1 and see what the reader says , that should be interesting.
Bryanj:
There is smething ese wrong with it somewhere as that is not ormal and carb slides dont alter
deltarider:
Best advice I can give, is to start from as stock as possible. Consulting Honda docs can be a great help, but... not when there is an error. You may read about an error in the page that deals with the initial carb set up. A German discovered this not that long ago. The correction he made, has already helped others. http://forums.sohc4.net/index.php/topic,184299.msg2133957.html#msg2133957 Not saying it is the cause, but the position of the slides - and thus the cut outs - is involved, so it wouldn't hurt checking you have the correct initial set up. It's quickly done.
A further addition. Don't make the mistake in trying to achieve a highest rpm* at idle by turning the air screws out. It is possible and the engine will pur like a kitten, but you will have a rotten acceleration. These CB500/550s need an idle mixture that is on the rich side, which - strange as it may sound - could imply having the slides a bit higher.
*This may be the correct procedure for other carbs. Ours are very basic and lack acceleration jets.
fogrider:
As far as I know, it is all standard and the carb settings right, including the 49mm thing. Idle screws down to 1 and 1/4 turns out.
I only bought it last October and the wiring mess was the priority and this year I set to re-painting the tank and side panels
so hardly ridden 'till recently. When I stripped the carbs to check the internals it seemed strange that the carb slides looked as new. It was off the road a while after the last owner died and someone since has re-built the wheels and I wonder if it's also had new slides - the wrong ones ?
It's remains a mystery, whatever I've checked or done.
Before I go overboard with slide mods, I checked the voltage to the coils. It revs free in neutral but bogs (when cold) on the road. That is typical of ignition faults and sure enough, there is a loss of 1 volt with the ignition on (but with the coils disconnected). No lights on. Some drain somewhere ?
It's still got the old type of reg and rec , I might try new , Podtronics OK ?
deltarider:
--- Quote from: fogrider on May 29, 2021, 01:25:36 PM ---As far as I know, it is all standard and the carb settings right, including the 49mm thing. Idle screws down to 1 and 1/4 turns out.
--- End quote ---
Try 11/2, 13/4 and 2 turns out and see what it does.
--- Quote ---... it seemed strange that the carb slides looked as new...
--- End quote ---
So do mine and they are 45 years old.
--- Quote ---I checked the voltage to the coils. It revs free in neutral but bogs (when cold) on the road. That is typical of ignition faults
--- End quote ---
Really?
--- Quote ---... and sure enough, there is a loss of 1 volt with the ignition on (but with the coils disconnected).
--- End quote ---
I'm afraid I can't follow you here. If you mean onboard voltage drops 1V when - with IGN key ON - kill switch is switched from OFF to RUN, that's not abnormal.
--- Quote ---It's still got the old type of reg and rec
--- End quote ---
Good, keep them, they rarely fail. Recently on the German site someone proved his stock regulator is actually better than electronic as it compensates somewhat for temperature, which none of the electronic ones do, not as far I know.
--- Quote --- , I might try new , Podtronics OK ?
--- End quote ---
Don't.
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