VHM cylinder head KTM 65 SX 24-27 / Husqvarna TC 65 24-27 / GasGas MC 65 24-27 + insert B 5.10 cc

HEAD AND INSERT INCLUDED: VHM head AA33217 + insert AE32353-B (combustion chamber 5.10 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) • AE32353-B — 5.10 cc • AE32353-C — 5.25 cc • AE32353-D — 5.40 cc (VHM standard) • AE32353-E — 5.55 cc • AE32353-F — 5.70 cc If in doubt, take the VHM standard: AE32353-D (5.40 cc). For the VHM piston with a 12° dome use the numbered inserts (AE32353-010, AE32353-020, AE32353-011, AE32353-021, AE32353-012, AE32353-022) — listed separately under VHM inserts. The 12° piston is not combined with a lettered insert. The manufacturer's chart in the photos shows the choice by fuel, track type (hard pack / deep sand) and elevation. Treat it as a starting point, not a fixed rule. BENEFITS • more engine power • better heat transfer • more resistance to detonation • exchangeable combustion chambers Spare O-rings: seal kit SK33112. Fits: Husqvarna TC 65 (2024–2027); KTM 65 SX (2024–2027); GasGas MC 65 (2024–2027).