Spanish company S3Parts’ new exhaust valve adjuster for KTM, Husqvarna and GASGAS two-stroke fuel injected (TPI) models – manual adjustments out on the trail made easy.

Off-road parts manufacturer S3Parts are more famous for their trials products but the enduro range is always expanding and, with riders like Mario Roman using their products, their name and reputation is growing.

This new exhaust regulator, or power valve adjuster if you prefer, is designed to fit for all TPI two-stroke engine KTM, Husqvarna and GASGAS 250/300 models from 2017 onwards.

S3Parts power valve adjustor highlights:

  • Ease of operation and installation
  • Instant motor feel change/reaction
  • Minimalist design means on the trail adjustments
  • Includes o-ring ready to install
  • Three anodised colour options

The beauty of this adjustor, apart from how good it looks, is that simple design that allows you to make adjustments in seconds – out on the trail if need be. Some riders find they need small adjustments to effect the power character depending on the riding conditions especially those spending their weekends heading up and down the mountains, changing altitude and hitting very different terrain in one day.

Homework time: this video from Tokyo Offroad is a really good explainer of how the TPI power valve works...


Take note. Adjusting the KTM/Husqvarna/GASGAS TPI power valve is not the same as with conventional, carburetted two-stroke engines. The valve itself is the same principle but KTM do not recommend you change it too much from standard setting (yellow marks lined up) or switch the secondary spring rate on a TPI engine.

Older carburetted two-strokes and also MX models normally take a green, yellow and red spring – green being stiffer and slower to open and therefore softer power characteristic, red the opposite with yellow in the middle.

These choices and what you do with your bike is up to you but KTM, Husqvarna and GASGAS recommend you seek authorised dealer advice if you think your bike is not running correctly or you want to adjust the feel of the power for trail, extreme or faster racing.

However, there are many examples in this online world of experienced bike and race shops explaining how you can adjust the TPI power valve to positive effect. We would always recommend you seek expert advice on this matter with the fuel-injected engines.

The reason for that is the many examples of people messing their bikes up by playing with this valve and the air/fuel screw and irreparably damaging their engine by doing the wrong thing. This S3Parts exhaust valve regulator is a sweet, new part but talk to the experts unless you know what you are doing.

Enduro21 hasn’t tested this adjuster, we've just taken a ‘first look’ at a product that caught our eye but we’ll try and get one tested asap.

Cost: TBA

Colours: Red, Orange, Blue


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