97 MXZ 670 plug black on one side
I just got back from a 200 mile ride on my 97 MXZ 670. The sled is new to me and is completely stock except for the exhaust. The sled ran great the entire time. It started without a problem every time. We had temps between -15 and 5 F. The sled had plenty of power top and bottom. I hit ~80 mph with plenty of throttle left. My problem is that when I checked the plugs after the 2 day ride I found the left side normal, but the right side black. It looked like carbon build up. I checked the air mixture screw and it was out 1 1/2 on both carbs. I backed out the right side 1 more turn and put fresh plugs in. I ran the engine on a stand and checked the plugs. The left was mostly dry, but the right was damp with some unburned fuel. I'd appreciate any advice on diagnosing the problem.