What is plug cap ?? This (1st Attachment) ?? If yes then change the whole cable ?? By the way why leak now ?? I didn't see any hole or something like that along side the cable. Also this cable connect to this components (2nd Attachment) .. should I change that together ??
yes, plug cap

leak when got water splash to it, then the plug cannot ignite becoz water short circuit the spark to ground

just change plug cap, google for pic, search shopee for pic
just unscrew the plug cap off the old cable and screw on the new one

I pay the price getting cold by examine the bike over 2 hrs in the heavy rain that day and just now I spray water directly into the spark plug area for like few mins but no luck to re-create the stutter and stop issue, may be the "free the water from the bottom bowl of the carburetor" trick that foreman show me really work ??   


Regardless I will definitely change my plug coil / plug lead / cap altogether because many people or google search mention it do bring back a good amount of engine performance in whatever condition after the old one already use for so long.

I pay the price getting cold by examine the bike over 2 hrs in the heavy rain that day and just now I spray water directly into the spark plug area for like few mins but no luck to re-create the stutter and stop issue, may be the "free the water from the bottom bowl of the carburetor" trick that foreman show me really work ??   


Regardless I will definitely change my plug coil / plug lead / cap altogether because many people or google search mention it do bring back a good amount of engine performance in whatever condition after the old one already use for so long.