61mm Aluminum Drop in cylinder kit for 125cc and 150cc GY6 engines, commonly referred to as a 171cc kit. In most cases, no special tools are needed for the job and no engine case machining is required! Old style GY6 engines may still require case machining, please see Specifications tab. Includes a light weight 3.6 ounce machined piston.

When used with a 57.8mm stock stroke crankshaft you get an honest 168.9cc displacement.

It is recommended to pair this kit with a 61mm head and upjet your stock carb or upgrade to a larger carb.

Made in Taiwan!

Please Note: Not for use with a stroker crank! 

• Cylinder Bore: 61mm
• Cylinder Skirt Outer Diameter: 62.8mm
• Piston Height: 31mm
• Piston Weight: 3.6 ounces
• Made in Taiwan
• Please Note: Not for use with a stroker crank! 

GY6 QMI/QMJ 152/157, Various unlisted makes/models

NOTE * WE HAVE USED THESE KITS WITH GREAT SUCCESS IN OUR MBX RACE BUGGIES

FROM OUR EXPERIENCE THESE WILL NOT FIT HOWHIT CASES. WE WERE ABLE TO GET AWAY WITH TRACING THE CYLINDER AND USING A DIE GRINDER.

WILL FIT CURRENT HAMMERHEAD AND TRAILMASTER ENGINES