xj1100j was running rough but now fixed

[windysolar1]

arrived for 35 days riding my xj1100j from the UK for the summer vacation
all was fine until i gaped the plugs and then it ran like a tank,missing,popping etc.
so my older bro desired it was time to clean the carbs in aboric acid for two hours each end and they were washed and sparkled.
after reassembly it ran sweet but i noticed it was running rough on idle again.
all the fuel pipes were in correct order.

now for the strange bit
I opened the plug gaps up to larger than spec and it now runs fine
no pops misses or farts

this one does not compute or make sense

would like to hear opinions on his matter