Product Details
Description
Engine Cases (Pair, Long, Big Bore, Custom); GY6
Key Details
- Custom SKU; SW Chicago must bore holes
Replacement Part Details
Use this part when the original component is worn, damaged, missing, or no longer working correctly. Many scooter parts can look similar but use different sizes, plugs, brackets, thread patterns, or mounting styles, so careful comparison before purchase is recommended.
Compatibility / Fitment
Use the fitment details below to confirm this part matches your scooter before ordering.
- Engine Size: GY6
- Fitment Notes: Big Bore
Fitment Guide: This compatibility information is based on manufacturer and supplier data. Listed models are common known applications and may not include every compatible scooter. If your scooter has multiple versions or production changes, confirm the correct match before ordering. Check photos, measurements, original part numbers, engine code, model, and related fitment information whenever possible.
Common Fitment Questions
Q: Is this for GY6 scooters?
A: This SKU is listed with GY6 engine-size fitment. Confirm exact model, year, and part style before ordering.
Additional information
| Weight | 10.7 lbs |
|---|---|
| Dimensions | 10 × 10 × 4 in |
Scooterworks offers our exclusive pair of Custom Big Bore Engine Cases for GY6 long engines. We machine these in matched pairs ourselves, and we bore them up to 63mm, big enough to fit a 63mm performance cylinder kit. Go big! Pick up a new crankcase gasket while you're at it.Â
- Matched right and left sides
- Stamped serial numbers ensure you have a matched set
- Dimensions: 10"L x 10"W x 4"H
157QMJ-based 125cc / 150cc / 169cc engines with the following engine codes:
| 157QMJ | 161QMK | 152QMI | 1P61QMK |
| YN1P57QMJ | 1P52FMI | 154FMI | JJ157QMJ |
| 1P57QMJ | BN157QMJ | BN161QMK-A | Other QMJ, QMK, and QMI models |
Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.
About Scooterworks: Since our beginning in 1989, Scooterworks has become a major supplier of parts and accessories for vintage and modern scooters. We have everything you need, from wear-and-tear items like tires and oil filters to aftermarket parts from brands like Malossi, NCY, Prima, YSS, Dr. Pulley, and more.
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.





