MXA TEAM TESTED: STEAHLY BOLT-ON KTM 250SX FLYWHEEL WEIGHT

WHAT IS IT? Bolt-on traction control for 2007?2014 KTM 250SX two-strokes.

WHAT’S IT COST? $119.95 (9 ounce and 11 ounce).

CONTACT? (800) 800-2363 or www.steahlyoffroad.com.

WHAT STANDS OUT?  Here’s a list of things that stand out with Steahly’s KTM 250SX 9-ounce flywheel weight.

(1) Weight benefits. Adding a flywheel weight increases the rotating mass, or inertia, of the engine. The most noticeable results are that the engine revs a little slower, stays in the powerband longer, is less likely to stall at slow speeds, starts easier and doesn’t fall off on top as quickly.

(2) Design. Steahly flywheel weights are easy to mount. You don’t even have to remove the stock flywheel from your bike (no flywheel puller required). Steahly flywheel weights are machined, balanced and trued out of solid steel billet. They slip over the existing flywheel weight and are held by a tolerance fit, threaded core and set screws. They can be installed and removed in as little as 15 minutes. Steahly flywheel weights are available in several different weights to suit each rider’s needs.

(3) Moments of inertia. A two-stroke uses a lighter flywheel than a four-stroke because it fires every stroke, compared to the four-stroke’s every-other firing pattern. Two-strokes don’t have to maintain momentum while waiting for the next explosion, thus two-strokes deliver a snappier and more abrupt style of power. A two-stroke’s rat-a-tat-tat power delivery is often too aggressive for riders bred on slower-revving four-strokes. This is where a flywheel weight comes into play. It can make a two-stroke feel torquier, broader and more hooked up.

(4) Horsepower. You might be tempted to think that a heavier flywheel would cost the KTM 250SX horsepower. Not so. It just makes each gear pull farther, stronger and longer. This is a bolt-on tuning trick that works. We preferred our 2013 KTM 250SX with the Steahly weight installed. We also run this weight on our KTM 300SX kit bike.

(5) Installation. The Steahly flywheel weight screws on top of the stock flywheel, and Steahly includes do-it-yourself instructions that give you two or three ways to get the flywheel nut off, even if you don’t have an impact wrench.

(6) Weight choices. Steahly’s bolt-on flywheel weights come in 9- and 11-ounce versions, plus Steahly will make custom weights. The MXA test riders prefer the 9-ounce weight.

WHAT’S THE SQUAWK? We have no complaints.

This simple mod improves the traction, usability and breadth of your fire-breathing, 50-horsepower KTM 250SX. That’s a good thing.