Bore Size: 5/8 inch Horse Power: Up to 6.5 HP # of Teeth: 10T Chain Size : #40/41/420 Engagement Speed: 2000??100 RPM; No Set Screw Holes. Two Set Screws are NOT included! Jeremywell Brand Centrifugal Clutch 5/8″ 10 Tooth Perfect Replacement For Go Kart Minibike Baja Mini Bike MB165 MB200 (Chain Size: #40/41/420) Set Screws and Chain Not Included – Centrifugal Clutch 10 tooth, 5/8″ bore with 3/16 key built in For 40,41,420 Chain 6.5HP – Common clutch for 3.5-7hp engines – Mounts onto crankshaft using bolt and washer on the end of the crankshaft. – Centrifugal Clutch 5/8″ Bore 10 Tooth For 40,41,420 Chain, Up to 7HP Engines. Common clutch for 3.5-7hp engines 2200 RPM – This clutch assembly with 3/4” shaft for 163cc 5.5 HP 196cc 6.5 HP Engines, which is the replacement Clutch Assembly. – It is a replacement that used on all versions of the Baja Mini Bike (MB165 MB200), including the Baja Heat, Mini Baja, and the Baja Warrior. Baja Part Number: 165-046