VHM cylinder head KTM 125 SX 16-22 / Husqvarna TC 125 16-22 / GasGas MC 125 21-23 + insert E 11.60 cc

HEAD AND INSERT INCLUDED: VHM head AA33156 + insert AE32257-E (combustion chamber 11.60 cc). Once fitted the head is ready to ride, nothing else to buy. Golden VHM two-stroke cylinder head with an exchangeable combustion chamber. It is designed to keep the engine's power throughout the whole race, not just the first laps: the improved water duct takes heat away from the combustion chamber more effectively. Made from a high-quality alloy and sealed with O-rings instead of a conventional gasket. WHAT THE INSERT IS AND WHY YOU NEED IT The VHM head has two parts: the golden cooled body and the chamber fitted into it — the insert. The insert sets the combustion chamber volume, i.e. the compression. Smaller volume = higher compression = more pull, but it needs higher-octane fuel. Larger volume = lower compression = the engine revs out more freely and tolerates pump fuel. When you change fuel, track or elevation you swap only the insert, not the whole head. WHICH INSERT TO CHOOSE (OEM piston) • AE32257-B — 11.20 cc • AE32257-C — 11.40 cc • AE32257-E — 11.60 cc (VHM standard: OEM piston) • AE32257-F — 11.80 cc VHM STANDARD INSERT • AE32257-E (11.60 cc) — OEM piston For the VHM piston with a 12° dome (APKT12511725) use the numbered inserts (AE32257-026) — listed separately under VHM inserts. The 12° piston is not combined with a lettered insert. BENEFITS • more engine power • better heat transfer • more resistance to detonation • exchangeable combustion chambers The vent screw M6×8 with its copper washer is included and already fitted. Spare O-rings: seal kit SK33156. Fits: Husqvarna TC 125 (2016–2022); KTM 125 SX (2016–2022); Husqvarna TX 125 (2017–2019); KTM 125 XC-W (2017–2019); GasGas MC 125 (2021–2023).