Free Power Only a Marker Line Away
by Jason Giacchino

We here at ATV Connection are big fans of free power and if there’s a way we can pass those gains onto you, we’re all for it.

Auto racers have used a technique known as “indexing” their spark plugs for additional horsepower for years but until recently, the results have been a bit less proven in the realm of ATVs.

The process itself is surprisingly simple: Making sure your plug is installed so that the spark itself will be in a position for optimal combustion conditions. The trouble is that performance junkies seem never to be in agreement with whether the electrode (and the corresponding spark) should be positioned to face the intake or exhaust valves for maximum output.

We’ve been doing some experimentation with both the KTM450XC and Suzuki LTR450 and in both cases yielded horsepower increases by positioning the plug’s electrode so that it was facing roughly ¾ toward the exhaust valve side.

So how does one go about ensuring that the electrode is in the desired position anyway? With the plug removed from the machine (always a good idea to install a fresh plug at this stage anyway), take a magic marker and draw a line right up the side of the top white porcelain section to indicate the electrode below.

With a little luck, you should be able to install the plug as usual and position your marker line by simply snugging up or loosening the plug slightly.

However- if it’s more than a quarter of a turn in either direction to reach the desired position, don’t risk over tightening the plug or running it too loose. Most automotive stores stock indexing washers for the exact purpose of allowing for proper installation torque while granting full control of the exact position of the electrode.