Odd Faultering Problem

I know this is a kz forum only but you guys are the absolute best so I'm am going to post here anyway, please don't get angry at me. The bike is a 1982 Honda Cb650SC. I have recently cleaned and rebuilt the carbs to spec, and put new spark plugs in. The bike ran well for the first five miles or so and now it seems to be fouling the plugs. The bike will run well under load until about 4-5 thousand rpms then it begins to stumble and will not exceed 7 thousand rpms. Although the bike revs freely to redline in neutral. Is this an issue with the coil? I am probaby going to have them bench tested at a dealership tommorrow but would like your feedback first.

Thanks,
Nate

Check your battery to see if it is dry. I had a similar problem with my 82 KZ-1000 CSR. I started fouling plugs and it ran rough at high RPMs. I spent days playing with the carbs and air filter. Eventually after it got real tricky to start I figured out that the battery was dry.

Another posibility is low voltage to your coil. Dirty Contact Points could be the problem if this is not an electronic ignition. It could be bad Spark Plug Wires or old Spark Plug Wire Caps for the plugs too.

Spock

Battery is fine and fully charged. Air Filter is clean. and it is an electic ignition system.

Thanks,
Nate

fuel level in the bowls and fuel flow from the tank is my first thought
next is the plug caps arcing to the engine

is compression up in the good range?
have your valves been checked?
did you check ignition timing?
do you have hot blue spark?
what are the floats set at ?

under load is when the bike needs good fuel flow and hot spark. and good sealing valves and rings.

fouled plugs can be from fuel or oil or weak spark

but coils are 4 or 5 down the list of details to be checked.