'Pa' has the flu

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‘Pa ’Has The Flu
Lately, ‘Pa’, my trusty mkiii has developed some symptoms like the flu, coughing, snorting, spitting, hesitation and temporary loss of power.

‘Pa’ has B/B ignition, single dual output coil, and single Mikuni. Starting is first or second kick, and idle is smooth and constant.

When driving on level road with the throttle just cracked open in second or third gear there is a hesitation and cough, sometimes once or twice, sometimes for five or so seconds and then runs fine for a second or a minute. With this is a cough from the intake (?) and a noticeable lack of power. This could better be described as a strong, irregular surge.

When this first started ‘Pa’ ran so bad he had to be accelerating or at idle, any attempt at steady throttle was impossible with heavy stuttering and stumbling. The next day he started and then stalled after idling for just a minute and would not restart. An examination of the NGK plugs showed the dreaded “Black Velvet”. Being in a hurry to catch up with some other riders I installed a set of platinum plugs and rode off. Now the Platinum plugs hide about half of the problem and the bike is just only tolerable to ride.

I went thru the Mikuni and removed a little dirt and water from the bowl and blew out the passages and he ran better for a few days, then back to his old ways. I have been thru the Mikuni twice more since and it seems to only marginally help for a little while.

Today, after a spirited 75-mile ride thru some beautiful fall colors in Kentucky, I removed the platinum’s for inspection and the left side is pure white and the right side is white with a little brownish color added. I switched back to an older set of Champions and ‘Pa’ is running better but not really right.

Besides getting a flu shot or dropping two aspirin in the tank, does anybody have any ideas?

Ride On
I would be inclined to think it may be an electrical problem, intermittent spark perhaps?

You say you have boyer ignition, is your battery in good condition/being charged consistently?

I have read your post, had a think & that is where I might start looking.
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