1971-1973 Arctic Cat Snowmobiles Factory Service Manual, Page 165Get this manual
SUSPENSION 7If the machine is equipped with speedometer, remove the drive head and disconnect the coupling cable from the drive shaftMove to the recoil side of the engineDisassemble the bearing retainer plate from the inside of the front end assembly by removing the three (3) carriage bolts and locknutsNOTE: Carriage bolt heads are located inside of the front end assembly; locknuts are located on the outside4
Release the drive chain tension by loosening the eccentric boltsSlide the eccentric either forward or backward until slack is obtained in the chain