VHM High-Compression Cylinder Head Insert for KTM 85 SX, Husqvarna TC 85 & GASGAS MC 85 – 7.80cc

The VHM AE32281-C 7.80cc cylinder head insert is an optional high-compression combustion chamber developed for KTM 85 SX, Husqvarna TC 85, and GASGAS MC 85 motorcycles equipped with the VHM AA33171 cylinder head.

Compared with the standard AE32281-E 8.00cc VHM insert, the smaller 7.80cc combustion chamber increases compression and shifts the engine character toward stronger low- and mid-range torque. This provides quicker acceleration, a more immediate bottom-end response, and increased drive when exiting corners.

This setup is particularly well suited to deep sand tracks and other conditions where stronger bottom-end power helps maintain momentum. The trade-off is reduced top-speed and over-rev potential compared with the standard or larger-volume chamber options.

The insert features a 7.80cc combustion chamber volume, +2.15 mm piston height, 0.80 mm squish, a dome piston crown profile, and a Ø47 mm bore.

VHM’s interchangeable combustion chamber system allows the insert to be changed quickly without replacing the complete cylinder head, making it easy to tailor compression and engine response to different track conditions.

The AE32281-C is precision-engineered for the VHM AA33171 cylinder head and features an engraved part-number reference for quick identification during servicing and engine setup.

This insert does not fit the OEM cylinder head and must be used with the VHM AA33171 head.

Key Features

• 7.80cc 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 characteristics
• Precision engineered exclusively for use with the VHM AA33171 cylinder head

Technical Specifications