VHM cylinder head KTM 250 SX 23-27 / Husqvarna TC 250 23-27 / GasGas MC 250 24-27 + insert G 23.00 cc

HEAD AND INSERT INCLUDED: VHM head AA33209 + insert AE32337-G (combustion chamber 23.00 cc, 95 RON fuel). 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) • AE32337-B — 21.00 cc, 110 RON fuel • AE32337-C — 21.40 cc, 105 RON fuel • AE32337-D — 21.80 cc, 102 RON fuel (VHM standard) • AE32337-E — 22.20 cc, 98 RON fuel • AE32337-F — 22.60 cc, 98 RON fuel • AE32337-G — 23.00 cc, 95 RON fuel If in doubt, take the VHM standard: AE32337-D (21.80 cc) for 102 RON fuel. For the VHM piston with a 12° dome (APKT25021754A1) use the numbered inserts (AE32337-021, AE32337-022, AE32337-023, AE32337-024, AE32337-025, AE32337-026) — listed separately under VHM inserts. The 12° piston is not combined with a lettered insert. BENEFITS • more engine power • better heat transfer • exchangeable combustion chambers The vent screw M6×8 with its copper washer is included and already fitted. Spare O-rings: seal kit SK33209. Fits: KTM 250 SX (2023–2027); Husqvarna TC 250 (2023–2027); GasGas MC 250 (2024–2027).