Me and my friend were woundering where the Raptors motor came from?

 

It started life as an air cooled 500 then 600xt Yamaha. About 1992, it became a water cooled 600 then a 660 in the European market. Yamaha used and uses the motor in their SZR and XTZ road and enduro machines. MZ bought the right to use the engine in their stuff as well. The engine road races in what Europe calls the "Supermono" class. That is where the BMW motor (dirt doo motor) can also be found.

Some of the differences include a cartridge oil filter on everything except the Raptor, reverse, a t crank in the Raptor vs. a full circle, weaker counter-balancer gears and timing chain in the early models (improved for the Raptor), slightly different gear clusters and other trans parts, etc.