VHM High-Compression Cylinder Head Insert for Yamaha YZ250 – 20.20cc
Optional 20.20cc VHM high-compression cylinder head insert engineered to increase low- and mid-range torque on Yamaha YZ250 2-stroke engines. Ideal for deep sand and traction-demanding conditions where stronger acceleration and corner-exit drive are more important than maximum top speed.
$79.99
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Product Description
The VHM AE32021-C 20.20cc cylinder head insert is an optional high-compression combustion chamber developed for Yamaha YZ250 2-stroke motorcycles equipped with the VHM AA33080 cylinder head.
Compared with the standard 20.60cc VHM insert, the smaller 20.20cc combustion chamber increases the compression ratio and shifts the engine character toward stronger low- and mid-range torque. This results in quicker acceleration, a more immediate throttle response, and increased drive when exiting corners.
The torque-focused setup is especially effective on deep sand tracks and other conditions where strong bottom-end response helps maintain momentum. The trade-off is reduced top-speed and over-rev potential compared with a larger-volume, lower-compression insert.
The AE32021-C features a +2.80 mm piston height, 1.50 mm squish clearance, a dome piston crown profile, and a Ø66.40 mm bore. Its combustion chamber is precision-designed to match the VHM AA33080 cylinder head.
VHM’s interchangeable insert system also allows combustion chamber configurations to be changed quickly without replacing the complete cylinder head, giving riders and engine tuners greater flexibility when adapting the motorcycle to different track conditions or performance requirements.
Because this insert increases compression, VHM recommends using high-quality fuel with suitable detonation resistance.
The insert features an engraved part-number reference for quick identification during maintenance or engine setup.
This insert is not compatible with the OEM Yamaha cylinder head and must be used with the VHM AA33080 head.
Key Features
- 20.20cc high-compression combustion chamber increases low- and mid-range torque
- Delivers stronger acceleration and improved drive when exiting corners
- Ideal for deep sand tracks and conditions that demand stronger bottom-end response
- Quick-change VHM insert design allows easy adjustment of engine power characteristics
- Designed for use with high-quality fuel to help reduce the risk of detonation
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | VHM |
| Part Number / SKU | AE32021-C |
| Product Type | Cylinder Head Insert / Combustion Chamber Insert |
| Insert Type | Optional / High-Compression |
| Engine Type | 2-Stroke |
| Engine Class | 250cc |
| Combustion Chamber Volume | 20.20 cc |
| Piston Height | +2.80 mm |
| Squish | 1.50 mm |
| Piston Crown Shape | Dome |
| Bore | Ø66.40 mm |
| Power Characteristic | Increased Low- and Mid-Range Torque |
| Recommended Use | Deep Sand / Torque-Focused Setup |
| Required Cylinder Head | VHM AA33080 |
| OEM Cylinder Head Compatible | No |
| Fuel Recommendation | High-quality, detonation-resistant fuel |
| Identification | Part-number reference engraved on insert |
| Make | Model | Year |
|---|---|---|
| YAMAHA | YZ 250 | 1999 - 2027 |
| YAMAHA | YZ 250 X | 2016 - 2027 |