YZ85 Platform
For years, the YZ85 was a 'lightswitch'—all top end, no bottom. The 2019+ update brought a power valve, finally giving it torque. Our engine packages are split into two philosophies: For 2019+ models, we optimize the YPVS to carry that new bottom end further into the over-rev. For older non-PV models, we perform extensive cylinder base work and head re-profiling to artificially create the torque the factory forgot.
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.
YZ85 Platform
85cc 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: YZ85 Platform
My YZ85 fouls plugs constantly. Will this fix it?
Yes. Plug fouling on YZs is usually due to inefficient combustion chamber shape (low turbulence). Our head re-profiling increases 'squish velocity,' atomizing fuel better so it burns clean.
Can you make my 2015 YZ85 competitive against a KTM?
We can get close. By raising the cylinder base and cutting the head, we change the port timing to favor low-end grunt, making the 'lightswitch' power delivery much more manageable.