Hey, I go thru about 6 spark plugs a month. i'm using the NGK B9ES mostly. I've tried the BR9ES but the same problem occurs so here it is; I'll be driving down the motorway just fine, speed will be good including good accel. The bike will come home and sit in the garage till the next day. Starting up will be one or two kicks but usually one. Driving, driving then power will start to bleed away until eventually one cylinder gets me home. A change of plugs and the situation is fixed only to re-occur again later.

The plugs seem to get damaged internally since they wont react to a spark generator after removal. Heat and mixture seems to be ok when reading the plugs on both cyl right after a good run.

I'm suspecting bad coils, internally broken HT leads or faulty HT caps. Any ideas on a solution?