DOMA Expansion Chamber for KAWASAKI KX 85, KX 100, KX 112 2002-2025

The DOMA 100047 expansion chamber is designed for KAWASAKI KX 85, KX 100, KX 112 from 2002 to 2025. On a two-stroke, the expansion chamber isn't just a pipe: its cones send back a pressure wave that fills the cylinder better at the right rpm. Its shape gives the engine its character, and a dented pipe costs power.

Key features

• Handmade in Calais, France.
• 1 mm raw steel, laser-cut parts, pressed and then welded on a jig.
• Developed on the dyno and on the track.
• Works with the stock silencer or a Doma silencer.

Specifications

• Brand: DOMA
• Manufacturer part number: 100047
• Engine: 2-stroke

Who is it for?

• Stock pipe dented or cracked after a crash.
• Looking for more response and more power.

Good to know

Competition use only: this pipe is not road-legal.

Fitting tips

1. Reuse the stock connecting O-rings if they're in good condition (not included), or fit a new exhaust gasket.
2. Offer up the pipe without forcing it, fit all the mounts, then tighten.
3. Warm up the engine and check for leaks at the joints.
4. Check the colour of the spark plug after the first few rides.

Why DOMA?

A French workshop based in Calais since 1992, Doma Racing designs and handbuilds two-stroke expansion chambers and silencers. A 125 world title in 2000 with Grant Langston and original equipment at KTM: a brand run by two-stroke enthusiasts.

Spare parts and items to plan

• Exhaust gasket : CENTAURO · ATHENA
• Spark plug : NGK R6252K · NGK

Frequently asked questions

Do I need to change the silencer?
No: the pipe works with the stock silencer or a Doma silencer.

Is it road-legal?
No: for competition use on closed circuits only.

Compatibility

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

Fits:
KAWASAKI KX 85 2025
KAWASAKI KX 85 2024
KAWASAKI KX 85 2023
KAWASAKI KX 85 2022
KAWASAKI KX 85 2021
KAWASAKI KX 85 2020
KAWASAKI KX 85 2019
KAWASAKI KX 85 2018
KAWASAKI KX 85 2017
KAWASAKI KX 85 2016
KAWASAKI KX 85 2015
KAWASAKI KX 85 2014
KAWASAKI KX 85 2013
KAWASAKI KX 85 2012
KAWASAKI KX 85 2011
KAWASAKI KX 85 2010
KAWASAKI KX 85 2009
KAWASAKI KX 85 2008
KAWASAKI KX 85 2007
KAWASAKI KX 85 2006
KAWASAKI KX 85 2005
KAWASAKI KX 85 2004
KAWASAKI KX 85 2003
KAWASAKI KX 85 2002
KAWASAKI KX 100 2021
KAWASAKI KX 100 2020
KAWASAKI KX 100 2019
KAWASAKI KX 100 2018
KAWASAKI KX 100 2017
KAWASAKI KX 100 2016
KAWASAKI KX 100 2015
KAWASAKI KX 100 2014
KAWASAKI KX 112 2025
KAWASAKI KX 112 2024
KAWASAKI KX 112 2023
KAWASAKI KX 112 2022