PowerDial FAQ

Q:   What does the PowerDial do?

A:    The PowerDial makes it possible to adjust the spring preload on KTM 250/300 power valves with no tools.  This makes trailside or trackside adjustments a snap.



Q:    How does a power valve work?

A:    The power valve (a.k.a. exhaust valve, exhaust control valve) alters the size of the exhaust port on a 2-stroke engine.  The “valve” is a metal flap that partially covers the exhaust outlet on the cylinder at low RPM.  As RPMs increase, the valve slowly opens.  This feature enables the motor to generate power over a broader RPM range.



Q:    What does the adjustment do?

A:    The power valve is held in the closed position by a spring.  You can change when the power valve opens by adjusting preload on this spring.  This affects the power delivery characteristics of your motor.



Q:    Which way should I turn the PowerDial?

A:    Turn the PowerDial counter-clockwise for an aggressive hit and maximum top-end power.  Turn the adjust clockwise for smoother power and a broader range of tractable low-end power.



Q:    Will I really notice a difference?

A:    Yes.  The power valve adjustment is very sensitive.  Most riders notice a 1/4 turn adjustment.  The full range of adjustment is 6 turns.



Q:    What bikes does it fit?

A:    The PowerDial fits KTM 250 and 300 2-stroke models from 1998 to 2017, KTM 125/150 models from 2016-2017, and Husqvarna 250/300 2-stroke models from 2014-2017.



Q:    How hard is it to install?

A:    Installation is simple.  No special tools are required and you don’t even have to drain the oil.



Q:    Will it interfere with my skid plate?

A:    Most skid plates are not a problem, but a couple full-coverage models create clearance issues with the PowerDial.  In these cases, skid plates must be modified to make room for the adjuster.



Q:    Can I still change the inner spring?

A:    Yes.  KTM’s interchangeable red/yellow/green springs are compatible with the PowerDial.  These springs alter the spring rate (not preload) and provide an additional tuning element.  The spring rate determines how quickly the power valve flap opens.  The spring preload (adjusted by the PowerDial) determines the engine RPM at which the power valve begins to open.



Q:    Why does my owner’s manual say not to adjust the powervalve spring preload?

A:    I don’t know – and apparently neither does KTM.  KTM sells a power valve adjustment tool in their Power Parts catalogue.



Q:    What is the stock setting?

A:    First, turn the PowerDial counter-clockwise until it stops.  From that position, count four full turns clockwise.  This is KTM’s stock setting.