Carbs

[Fourthegoodtimes]

 
I have just finished putting together my 1976 US import CB 550 K, but I have a carb problem. First time of starting I got nothing on number 2 cylinder,followed shortly by petrol overflow from number 2 carb. No problem remove the carbs that took me three hours to fit, take float bowl off to find floats stuck and LOADS of gunge. Spend next two nights cleaning everything in sight with carb cleaner, took floats and all the jets out. Reset float level and reassembled. Whilst at it took all the others apart as well. Connected carbs up to fuel supply BEFORE refitting to check for leaks..........none or any overflow either. Spent another two hours refitting tonight and...........................still nothing on number 2!!! I have checked points and plugs ( new ) and have healthy spark. Where do I go next...................

[SteveD CB500K0]

Is plug #2 wet?

That'll prove if fuel is getting in at all.

[totty]

Check the compression if you have a gauge. Also swap the plug with another cylinder just to totally rule it out.

[flc]

I always start with what i was told is a

[SteveD CB500K0]

I've also seen duff plugs act like that, albeit on my old Escort and not on a bike.

New plug had a fault that meant it would spark against the cylinder head but not when on the compression stroke.

[florence]

I too have seen this problem with plugs.  Move the plug from the non running cylinder to a running cylinder and see if the problem moves with the plug.

[Fourthegoodtimes]

 
Thanks to everyone who responded. It WAS the plug!! I cannot ever remember having a new plug fail but that is what has happened. Replaced it with one of the old originals and I now have a 4 rather than a triple.

[matthewmosse]

I've had a lot of plugs do this recently. normally after a few minutes running, I was assuming it maybe was contamination of the 2 stroke oil on my kh (really really frustrating on a single, I normally carry a spare plug but when 2 new in a row are dud thats taking the biscuit!) seems to be a more common thing these days, might be the issue that ended up with my 500/4 outfit finally retiring to the project list and cirtainly high up on the to do list when house renovation is done and I can play in my shed again.