I have abouy 200 miles on my wr, and this weekend when I went up north to ride, the plug fouled out. I put another plug in it, it ran fine for about a 10 minute test, however the next day when I took it out again the bike was sputtering and backfiring. After about 15 minutes on this ride it seemed to clear up a bit. I did not have time to check plug again but I'm assuming it would be on the black side. The only difference riding this weekend was the weather, I usually ride in 70+ degree conditions in the summer (this past summer 80 to 90), this weekend it was 50 degrees where I was riding. I have uncorked exhaust, no lid, grey wire disconnected, and stock jetting. Would the colder weather make it foul out? I checked the plug at about 100 miles and it was looking pretty black this summer, but running pretty well. The only thing I would notice is a bit of cutting out when on the throttle in about fourth gear. Any info would be appreciated.