VHM Cylinder Head for TM RACING EN 125, MX 125, MX 144 2012-2025

The VHM AA33142 cylinder head is designed for TM RACING EN 125, MX 125, MX 144 from 2012 to 2025. The cylinder head closes off the top of the cylinder and forms the combustion chamber. On a two-piece VHM head, the chamber is a machined insert that can be swapped in a few minutes to adapt the engine's compression.

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: AA33142
• 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?

Founded in 1995, VHM specialises in racing engine parts for motocross, road racing and karting. The brand started out with cylinder heads featuring interchangeable combustion chambers, which became its speciality, and then developed crankshafts, connecting rods and gasket kits.

Spare parts and items to plan

• Top-end gasket kit : VHM SK33000.VITON · VHM SK33000
• Coolant : MOTUL 1 L · LIQUI MOLY 1 L

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:
TM RACING EN 125 2021
TM RACING EN 125 2020
TM RACING EN 125 2019
TM RACING EN 125 2018
TM RACING EN 125 2017
TM RACING EN 125 2016
TM RACING EN 125 2015
TM RACING EN 125 2014
TM RACING EN 125 2013
TM RACING EN 125 2012
TM RACING MX 125 2024
TM RACING MX 125 2023
TM RACING MX 125 2022
TM RACING MX 125 2021
TM RACING MX 125 2020
TM RACING MX 125 2019
TM RACING MX 125 2018
TM RACING MX 125 2017
TM RACING MX 125 2016
TM RACING MX 125 2015
TM RACING MX 125 2014
TM RACING MX 125 2013
TM RACING MX 125 2012
TM RACING MX 144 2025
TM RACING MX 144 2024
TM RACING MX 144 2023
TM RACING MX 144 2022
TM RACING MX 144 2021
TM RACING MX 144 2020
TM RACING MX 144 2019
TM RACING MX 144 2018
TM RACING MX 144 2017
TM RACING MX 144 2016
TM RACING MX 144 2015
TM RACING MX 144 2014
TM RACING MX 144 2013