VHM High-Compression Cylinder Head Insert for KTM 250 SX, Husqvarna TC 250 & GASGAS MC 250 – 21.80cc

The VHM AE32272-C 21.80cc cylinder head insert is an optional high-compression combustion chamber developed for KTM 250 SX, Husqvarna TC 250, and GASGAS MC 250 2-stroke motorcycles equipped with the VHM AA33166 cylinder head.

Compared with the standard AE32272-E 22.20cc VHM insert, the smaller 21.80cc combustion chamber increases the compression ratio and shifts the engine character toward stronger low- and mid-range torque. This results in quicker acceleration, more immediate throttle response, and increased drive when exiting corners.

This torque-focused setup is particularly effective on deep sand tracks and other conditions where strong bottom-end response helps maintain momentum. The trade-off is reduced over-rev and top-speed potential compared with the standard or larger-volume chamber configurations.

The insert features a 21.80cc combustion chamber volume, +3.70 mm piston height, 1.60 mm squish, a dome piston crown profile, and a Ø66.40 mm bore.

VHM’s interchangeable combustion chamber system allows the insert to be changed quickly without replacing the complete cylinder head, giving riders and engine tuners the flexibility to adapt engine characteristics to different track conditions and performance requirements.

Because the AE32272-C increases compression, VHM recommends using high-quality fuel with suitable resistance to detonation.

The insert is precision-engineered for the VHM AA33166 cylinder head and features an engraved part-number reference for easy identification during servicing and engine setup.

This insert is not compatible with the OEM cylinder head and must be used with the VHM AA33166 head.

Key Features

• 21.80cc high-compression combustion chamber increases low- and mid-range torque
• Improves acceleration and delivers stronger engine response when exiting corners
• Ideal for deep sand tracks and traction-demanding motocross conditions
• 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