Here are some bikes that have been around for awhile. One of the great things about riding on the ice is that some of the older bikes are just as much fun to ride, and aren't as obsolete as they would be on a motocross track or in the woods. Plus they have some character and funk that doesn't really come out on the newer bikes...
This is a late '70s Yamaha YZ460 that was racing at Lake George, the owner was racing in Senior A class. The ice fenders on this bike were very well made.
1982 Honda CR250, liquid cooled, Canadian tires. I get to ride this bike occasionally and it's always a treat, handles great and has surprising power. Lots of fun.
'78 Suzuki RM250, air-cooled, pipey. Also on Canadian tires. A bit more of a challenge to make it go fast because you have to keep it on the pipe, but very satisfying when you get it right.
These two are owned by one of my ice ridin' buddies, pictured here checkin' the tires, Mike, super nice, super fast. We just had a great session, he was riding the CR, I was on the RM and Matt was strafing us on his KTM. Mike and I had some great laps, pushing each other (and the bikes) pretty hard.