year i have no idea would guess early to mid 70's?? The high pipes were popular at the time on a lot of bikes, Triumph used em Yamaha used em etc...on smallish displacement "Scrambler" style bikes, designed for multi-use on paved and dirt roads and semi off road use, alot of people fitted them with knobbies, for dirt use. The pipes were set high to avoid damage from brush and rocks and debris. They were popular amongst dirt and ice trackers, and even road racers. Never owned one myself but there are at least a couple of guys here that do and they seem to be very good bikes.