VHM head insert KTM 85 SX / Husqvarna TC 85 25-27 / GasGas MC 85 25-27 – C 6.80 cc

Exchangeable combustion chamber (insert) for the VHM cylinder head AA33222. Chamber volume 6.80 cc. 🔴 The insert fits ONLY the VHM head AA33222 — it cannot be fitted into the OEM head. For the stock (OEM) piston. Compared with the VHM standard (7.00 cc) it has a smaller volume, i.e. higher compression: the engine pulls harder but needs higher-octane fuel, otherwise it may detonate. Quick to change — the insert simply sits in the head and seals with O-rings. The last characters of the part number are engraved on the insert, so you cannot mix them up. The manufacturer's chart in the photos shows the choice by fuel, track type and elevation. Use it as a starting point. Fits: KTM 85 SX (2025–2027); Husqvarna TC 85 (2025–2027); GasGas MC 85 (2025–2027).