Blue Line Big Bore Kit w/ Head 4T (72cc, 64mm Valves); 139QMB
Blue Line Big Bore Kit w/ Head 4T (72cc, 64mm Valves); 139QMB
$83.34
10 in stock
*Note: Free shipping to U.S. mainland (excludes AK, HI, and territories)
Orders placed by 1pm EST on weekdays ship the same day.
Product Details
Description
Blue Line Big Bore Kit w/ Head 4T (72cc, 64mm Valves); 139QMB
Key Details
- Original Parts For Scooters SKU: 151-280-47mm
Compatibility
Fits many 139QMB-based 50cc / 80cc scooter engines. Confirm measurements, connector style, and engine family before ordering.
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: 50cc, 80cc, 4-Stroke
- Engine Code: 139QMB
- 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: Will this fit a 139QMB engine?
A: This SKU is listed as compatible with 139QMB engine-code fitment. Always compare your original part and scooter details before ordering.
Q: Is this for 50cc scooters?
A: This SKU is listed with 50cc engine-size fitment. Confirm exact model, year, and part style before ordering.
Additional information
| Weight | 4 lbs |
|---|---|
| Dimensions | 6 × 6 × 6 in |
Blue Line Complete 72cc High-Performance Big Bore Cylinder Kit for 50cc 4-stroke 139QMB engines.
Original Parts For Scooters SKU 151-280-47mm
NOTE: Before ordering, remove the valve from your scooter's head and measure the full length of the valve stem. This kit works with 64mm valves. If your scooter has 69mm valves, you'll need the following 69mm big bore kit.
Pump up that weak engine to a respectable 72cc displacement, on a budget. This kit is not intended to make your scoot a screaming race machine. It is intended to get you that extra power you need. (Most Chinese 50cc's only put down around 1.5hp to the ground.)
- 1 - Head Assembly with 64mm valves
- 1 - Iron Cylinder with 47mm bore
- 1 - Piston with Rings (Not Pictured)
- 1 - Wrist PinÂ
- 2 - Circlips
- 2 - Exhaust studs
- 2 - Intake Studs
- 1 - Base Gasket
- 1 - Head Gasket
139QMB-based 50cc / 80cc engines with the following engine codes:
| 139QMA | 139QMB | 1P39QMB | 1P39QMA-2 |
| YN139QMB | JJ1P39QMB | 139FMA-2 | BD1P39QMB |
| BN139QMB | 147QMD | Other QMA models | Other QMB models |
Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.
About Blue Line: Blue Line offers OEM equivalent replacement parts for on-road scooters. Blue Line parts are a direct-fit replacement when OEM parts are unavailable or overly expensive for your scooter. Since 2018, Blue Line has provided quality parts at great prices.
