VHM Cylinder Head for YAMAHA YZ 125 and FANTIC XE 125, XX 125 2005-2021

The VHM AA33077 cylinder head is designed for FANTIC XE 125, XX 125 and YAMAHA YZ 125 from 2005 to 2021. A VHM cylinder head is made up of an aluminium body and an interchangeable insert that forms the combustion chamber. By swapping the insert, you set the engine's compression and character to suit the fuel and the terrain, without modifying the head.

Key features

• Two-piece cylinder head: body and interchangeable combustion chamber insert.
• Compression adjustable by swapping the insert, without removing the cylinder.

Specifications

• Brand: VHM
• Manufacturer part number: AA33077
• Engine: 2-stroke

Who is it for?

• Original head damaged by pinking (detonation), cracked or warped.
• You want to match the compression to the fuel, the terrain or a tuned engine.
• You're after a smoother or snappier engine without changing the cylinder.

Good to know

The insert is chosen to suit your engine and your fuel: a smaller chamber volume raises compression, which may call for a higher-octane fuel. Always check the squish when fitting.

Fitting tips

1. Clean the cylinder mating face without scratching it.
2. Fit new O-rings and grease them lightly so they stay in place.
3. Check the squish (gap between piston and head) with solder wire before riding.
4. Tighten the head in a criss-cross pattern, in several stages, to the recommended torque.
5. Fit a new spark plug and refill the coolant.

Why VHM?

Since 1995, VHM has been designing racing engine parts for two-strokes: cylinder heads with interchangeable inserts, combustion chamber inserts, crankshafts and connecting rods. A specialist brand, used to fine-tune an engine's power without transforming it.

Spare parts and items to plan

• Top-end gasket kit : ATHENA · ATHENA 150
• Spark plug : NGK 3530 · NGK 3230
• Coolant : LIQUI MOLY 1 L · TWIN AIR

Frequently asked questions

Can I change the compression later?
Yes: just swap the VHM insert, without removing the cylinder.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
FANTIC XE 125 2021
FANTIC XX 125 2021
YAMAHA YZ 125 2021
YAMAHA YZ 125 2020
YAMAHA YZ 125 2019
YAMAHA YZ 125 2018
YAMAHA YZ 125 2017
YAMAHA YZ 125 2016
YAMAHA YZ 125 2015
YAMAHA YZ 125 2014
YAMAHA YZ 125 2013
YAMAHA YZ 125 2012
YAMAHA YZ 125 2011
YAMAHA YZ 125 2010
YAMAHA YZ 125 2009
YAMAHA YZ 125 2008
YAMAHA YZ 125 2007
YAMAHA YZ 125 2006
YAMAHA YZ 125 2005