Hi Everyone. I'm new to Snowmobile world.com and snowmobiling in general. I picked up a 1984 safari 377. Did the usual stuff to something that had been sitting a while; changed out old fuel, cleaned carb, new fuel lines, new plugs, etc... I have taken it around my yard a few times to get a feel for it and to aggravate my nosey neighbors. I took it out today and had my first real run with it. Rode about 3 1/2 hours almost constantly with minimal breaks. Towards the end of the ride the motor started to ping. A very high pitched ping. I shut it down and let it sit for about 10 minutes and restarted the motor. Ran about 5 minutes before ping came back. I have not pulled plugs yet to check for fouling. I'm thinking possibly just overheating. Any ideas?