and the CR500 used an expansion chamber design that purposely snuffed the high end hit.... they would put out over 75 Hp by swapping on a "desert" pipe, and doing some mild porting.... i was adding about 2lbs to the flywheels to get them to hook up in the woods.... Chucky Stealhy made the weights removable...he rode one of my KX 500 woods conversions... the rest is history.

just looked...my tandem is a 1" headset... it was a 5 speed freewheel, originally, and it still has the reverse op. suntour front der...so.. yep, quite OLD.
that bike was well used, and well loved... the baby blue paint is nearly perfect.