Yamaha YZ250 Head Fix & Porting
Eliminate the 'Yamaha Ping' and gain massive torque. Our YZ250 head re-profiling service corrects the dangerous factory squish clearance for safe pump gas operation.
The Stock Bottleneck
"Severe detonation ('pinging') on pump gas due to loose factory squish clearance."
The HP Race Dev Solution
"Re-profiling the head to tighten the squish band, eliminating pinging and sharpening throttle response."
We don't just "grind ports." We mathematically correct the engine's geometry to solve this specific flaw.
Engineering the YZ250 Platform
The stock YZ250 squish clearance is often greater than 1.8mm. This wide gap creates end-gas pockets that spontaneously combust (detonate) under load, known as 'pinging.' This can destroy pistons. We machine the head to bring this gap down to a safe, efficient 1.2mm.
By tightening the squish band, we increase the turbulence of the fuel-air mixture as the piston reaches Top Dead Center. This forces the mixture towards the spark plug for a faster, cleaner burn. This eliminates the need for race gas just to run safely.
A proper squish clearance also improves cooling efficiency by transferring heat from the combustion chamber to the cooling jacket more effectively. The result is an engine that runs crisp, cool, and deto-free on 93 octane.
Select Your Level
Choose the package that fits your racing class.
YZ250 Platform
250cc 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: YZ250 Platform
Why does my YZ250 rattle when I accelerate?
That is detonation (pinging), caused by the loose factory head specs. Our 'Minimum Spec' package fixes this immediately by re-profiling the cylinder head for proper combustion.
Can you build a YZ250 for woods racing?
Yes. We retard the ignition timing and alter the exhaust port height to lower the powerband, turning the violent motocross hit into a tractable, torque-heavy enduro weapon.