TrailMaster MK125S Pro Series Dirt Bike, 4-Speed Semi-Automatic, Electric Start, Dual Disc Brakes, (14/12) Wheels

      The TrailMaster MK125S Pro Series is a premium mid-size dirt bike built for riders who want upgraded suspension, stronger components, and smooth power delivery without the complexity of a full manual clutch. Powered by a reliable 125cc air-cooled 4-stroke engine, it delivers consistent performance, solid torque, and dependable off-road capability.

        This model features a 4-speed semi-automatic transmission, meaning riders can shift through gears without using a manual clutch perfect for learning control while still getting a more advanced riding experience. With electric start plus kick-start backup, inverted front suspension, nitrogen rear shock, and 14-inch front / 12-inch rear wheels, the MK125S is built for improved handling, comfort, and trail stability.

Designed for riders ages 12 and up, it’s a strong step-up bike for teens and adults who want a higher-performance trail machine with modern Pro-Series upgrades.

Performance Specs:

Engine

• 125cc Single-Cylinder, 4-Stroke, Air-Cooled Engine (Zongshen balanced shaft platform)
• 123cc Displacement
• 4-Speed Semi-Automatic Transmission (no manual clutch required)
• Automatic Clutch System
• Electric Start with Kick Start Backup
• CDI Ignition System
• Chain Drive System
• Maximum Power: ~6.3 HP
• Maximum Torque: 8.8 N·m @ 5500 RPM
• Compression Ratio: 9.0:1
• Fuel Consumption: ≤367 g/kW·h

Fuel System

• Fuel Capacity: 0.92 Gallons
• Carbureted Fuel System
• EPA-compliant 4-stroke setup
• Recommended Oil: 10W-40

Suspension

• Front: Inverted hydraulic forks (race-style setup)
• Rear: Nitrogen gas mono shock
• Aluminum linkage system
• Designed for improved impact absorption and trail control

Braking System

• Front Hydraulic Disc Brake
• Rear Hydraulic Disc Brake
• Dual disc braking system for strong stopping power

Wheels & Tires

• Front Tire: 60/100-14 knobby off-road tire
• Rear Tire: 80/100-12 knobby off-road tire
• 14-inch front wheel / 12-inch rear wheel setup
• Alloy wheels with hub system
• Off-road tread designed for grip and traction

Dimensions

• Overall Size: 63 x 27 x 42 in
• Wheelbase: 31 in
• Seat Height: 29–29.5 in
• Ground Clearance: 10.2 in
• Compact mid-size frame geometry for control and agility

Frame & Construction

• Reinforced steel frame
• Aluminum linkage components
• Foldable alloy levers
• Performance exhaust system
• Waterproof wiring harness

Weight

• Net Weight: 149lbs
• Gross Weight: 213lbs

Additional Features

• Electric start + kick start backup
• 4-speed semi-automatic transmission (no clutch)
• Inverted front suspension for improved handling
• Nitrogen rear shock for smoother ride quality
• Lightweight mid-size chassis design
• Built for trail riding, off-road use, and recreational riding
• Available in Red, Blue, and Green
• Recommended Rider Age: 12+ Years

What's Included

✔ TrailMaster MK125S Pro Series Dirt Bike
✔ Electric Start Battery
✔ Kick Start System
✔ Tool Kit
✔ Owner’s Manual
✔ Assembly Hardware & Instructions