For the past couple of days my '97 BMW f650 has been running like crap. It wouldn't idle below 1500 rpm, it was surge-y and rough at neutral throttle, and seemed a bit down on power... I thought I had got some bad gas, and was just trying to run it through... Then I refilled the tank with fresh gas and it was still running like crap, not unusable, just shitty. I drained the float bowls and tried again... Same shit... Damn. For those of you unfamiliar, the bike uses a 652cc Rotax single with a massive over-square piston that measures 100mm across. It has two 33mm Mikuni carbs and 2 spark plugs. I had already wiggled the outboard plug wire to make sure it was tight, but I hadn't bothered to reach in and check the inboard plug... Turns out the second plug wire was loose! I pushed it on tight, and voila! Runs like a top again! I guess that second plug is in fact rather vital to proper flame propagation across that saucer-sized piston surface. who'da thunk?