My plan was to finish other projects before coming back to this to fix it but It is just too frustrating. It runs rich, plugs are completely black, doesn't return to idle without bliping throttle or forcing it back down by rolling throttle forward, when it does idle it is anyones guess if it will stay or stumble.
This is after just one ride after wire brushing the carbon off, before cleaning they were completely caked and all are like this.
It blows through the holes in my exhaust and you can see the carbon build up on the outside.
1972 CB500 k1: It is stock as can be, stock carbs, stock settings and jets(*we'll get back to this later), stock airfilter, carbs were completely cleaned 2 years ago, and it always ran like this so dirt isn't a problem. Valves, timing, points gap, new plug caps, everything I can think of for a tune up was done.
My theories so far:I bought the bike partially in boxes so I don't know how it ran with the exhaust that came with it (last inspection was 1989). The exhaust it came with was 4 into 2 and more open than stock. Despite the jets saying they are stock 100 main and 40 pilot, I guess it is possible the po drilled them out for a different exhaust. If everything else fails, next step is to buy new stock jets from jetrus.
The only other thing I can think of is maybe the coils or ignition system in general is weak. I remember checking them with a multi-meter 2 years ago and put them back on but I don't remember the numbers. Can a weak ignition cause this rich condition? Any help is appreciated, I'm almost to the point of throwing money at the problem with new jets and maybe a electronic ignion and dyan coils.
