Get more speed and a more usable rev range out of your GY6 big bore kit with this 15*37 upgear set from NCY. This kit is a 20% upgear ratio from the stock 13*40 gear set. 

Specifications:

• Front Counter Shaft Teeth: 15
• Front Counter Shaft Dimensions: Spline L: 24mm, OD: 31.1mm, Overall L: 60mm
• Gear Press-On Area L: 12.08mm x OD: 19.08mm, Ends L: 9<10.5mm x OD: 15mm
• Rear Final Drive Gear Teeth: 37
• Inner Spline: 19, OD: 71.2mm, ID: 18mm, W: 20mm

NOTE: You're going to need access to a 12-ton hydraulic compressor to remove the stock counter shaft gear from the counter shaft, and then again to re-press the new NCY counter shaft gear.

Compatibility:

157QMJ-based 125cc / 150cc / 169cc engines with the following engine codes:

Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.

About NCY: NCY is the aftermarket performance parts leader for most popular scooter brands including Honda, Yamaha, Genuine, Vespa, SYM, Lance, KYMCO, and GY6 / QMB powered scooters. Made in Taiwan with strict quality standards since 1997, NCY is ISO 9001 certified.

Made in Taiwan.

This product is intended for off-road use only.

This product is not intended for use on public roads or land.

This product is not legal for use in California on pollution-controlled vehicles. Check local laws before installing.

*Performance upgrades are considered racing parts and are not covered by warranty.