This insert with 20.50cc volume is the VHM standard for Yamaha YZ250 1988 - 1998 and is developed for the best overall performance. The combustion chamber fits the VHM cylinder head perfectly and is easy to change. The last numbers of the part number are engraved on the insert for indentification.
Use in combination with VHM head AA33187
- Best overall performance
- Quick to adjust