Universal Parts Standard CVT Drive Belt 681-17.7-30
Universal Parts Standard CVT Drive Belt 681-17.7-30
$26.77
Out of stock
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Product Details
Description
Universal Parts 681-17.7-30 Belt – 139QMB-B CVT Transmission
Key Details
- 106-92
Specifications
- Length: 681mm Top Width: 17.7mm Groove Angle: 30° QMB139 50cc/49cc , Roketa, Various unlisted makes/models
- Width: 17.7mm Groove Angle: 30° QMB139 50cc/49cc , Roketa, Various unlisted makes/models
Compatibility / Fitment
Use the fitment details below to confirm this part matches your scooter before ordering.
- Engine Size: 49cc, 50cc, QMB139
- Engine Code: QMB139, 139QMB
- Fitment Notes: CVT, Universal Fit, Auto Transmission
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 QMB139 engine?
A: This SKU is listed as compatible with QMB139 engine-code fitment. Always compare your original part and scooter details before ordering.
Q: Is this for 49cc scooters?
A: This SKU is listed with 49cc engine-size fitment. Confirm exact model, year, and part style before ordering.
Additional information
| Weight | 0.3 lbs |
|---|---|
| Dimensions | 7 × 4 × 2 in |
| Size | 681×17.7×30 |
681-17.7-30 Belt
Restore the smooth power delivery of your 50cc scooter with the Universal Parts Standard CVT Drive Belt. Specifically sized at 681-17.7-30, this belt is the dedicated replacement for the 139QMB-B engine platform. While standard 50cc belts may slip or cause gear-ratio inconsistencies, this belt is manufactured to the exact width and length specifications required for the "B-Case" transmission, ensuring a crisp throttle response and a stable top speed.
Technical Performance Features
- Optimized "B-Case" Fitment: The 681mm length is specifically tailored for the slightly different pulley spacing found on 139QMB-B engines, preventing the "slap" and vibration associated with incorrect belt sizing.
- Durable Composite Construction: Features a high-tensile internal cord structure designed to resist stretching under load, maintaining consistent RPM across your powerband.
- 30 ° Performance Groove: Engineered with a precise 30-degree side-wall angle to provide maximum grip against your variator and clutch faces, reducing heat buildup and power loss.
- Reliable Heat Management: Constructed from a robust rubber compound that maintains flexibility and grip even during long-distance urban commuting.
Comprehensive Fitment Guide
This belt is a primary fit for 50cc 4-Stroke (139QMB-B) scooters and specific "B-series" chassis. Please verify your engine code before ordering:
| Engine Type | Common Brands/Models |
|---|---|
| 139QMB-B | Roketa, TaoTao, and various "B-Series" imports |
| 49cc / 50cc 4-Stroke | Specific models requiring the 681mm length profile |
| B-Case Transmission | Generic Chinese "Street Legal" 50cc scooters |
Technical Specifications
- Length: 681mm
- Top Width: 17.7mm
- Groove Angle: 30 °
- Engine Code: 139QMB-B / QMB139-B
Mechanic's Note: The "B" in 139QMB-B signifies a specific transmission variation. Using a standard 669 or 729 belt on this engine will result in poor acceleration or belt failure. Pro Tip: Check your CVT Air Filter when you replace this belt; a clogged filter causes the belt to run hot, leading to the glazing and snapping you're trying to avoid!
SKU: 106-92
MPN: 3059
Vendor: Universal Parts
