MC 125 Platform
The 125 two-stroke is the purest expression of fluid dynamics in motocross. Stock cylinders often suffer from 'short side radius' issues in the exhaust port, choking off over-rev. We utilize specific time-area (STA) calculations to reshape the exhaust port, allowing the engine to breathe freely at 12,000 RPM. Whether you're fighting for a holeshot or just want that factory sound, our 125 packages are purely mathematical aggression.
The Stock Bottleneck
"Factory limitations holding you back."
The HP Race Dev Solution
"Engineered performance."
We don't just "grind ports." We mathematically correct the engine's geometry to solve this specific flaw.
Select Your Level
Choose the package that fits your racing class.
MC 125 Platform
125cc PlatformMinimum Spec
Reliability, clean-up, throttle response. The entry-level fix.
- •Cylinder Truing & Casting Cleanup
- •Power Valve Mechanism Check & Calibration
- •Deck Height Verification
Recommended For
Local Racing & Practice Bikes
Privateer Spec
The sweet spot. High performance, durable enough for a full season.
- •Stage 2 Cylinder Porting
- •Cylinder Head Machining (Squish & Combustion Chamber)
- •Exhaust Port Polishing
- •Carburetor Taper Bore
Recommended For
Regional Championships & Competitive Stock Class
Factory Works Spec
No compromise. Maximum power, exotic coatings, extensive labor.
- •Stage 3 Full Race Porting
- •Engine Case Matching (Blueprinting)
- •Ceramic Coatings (Piston Crown & Combustion Chamber)
- •ISF Process Transmission Tumbling
- •Dynamically Balanced Crankshaft
Recommended For
Loretta Lynn's, Mini Os, Pro Nationals
Common Questions: MC 125 Platform
Will a 150cc kit ruin my top end?
Only if not ported correctly. 150s naturally sign off earlier than 125s. We port 150 cylinders specifically to restore that '125-like' over-rev while keeping the big-bore torque.
Is case matching worth it on a 125?
Absolutely. On a small displacement engine, every bit of turbulence in the crankcase robs you of throttle response. It is the secret to a bike that feels 'connected' to the throttle.