Replacing a legend is always a risk. For the past seven years, the KTM 520 and 525 have been the ruling class of off-road four-strokes. The joy of a magnum four-stroke is big torque, and first the 520s and then the 525s had plenty of the four-stroke goodness that thumper-lovers crave-arm-wrenching torque and big-time boost in a slim package sporting a low center of gravity and that magical six-speed gearbox. Being off-road experts, KTM didn't make power that overpowered the chassis or the rider in tight conditions, but still geared the bikes for over 100 mph (they won't pull the gearing unless conditions are flawless, but it's there). Sure, most of us don't need or want to see "the ton" on a dirt bike, but stitching together fun single-track trails with open sections is a lot more fun when the bike's motor is loafing at 55 to 65 mph.
KTM's 530 XC-W(R) is all-new mechanically, but the 525 design philosophy aiming at a slim, tractable, long-lasting and easily maintained dirt bike lives on. Like the 525, the 530 is a six-speed and remains a single-cam engine, but the list of actual engine or chassis parts that will interchange with a 525 is very short indeed. The castings are modern in appearance with crisp lines, but the changes weren't for looks.
It doesn't take even one mile to realize that this new 530 engine avoids all the weaknesses we ever noticed about the RFS engine family, and some we never noticed. The clutch pull is light and smooth, engine vibration hardly deserves mention and power is up everywhere. The added muscle doesn't make the 530 harder to ride, or more bottom power makes it easier to handle in technical riding. The 530 is happier riding at extreme low rpm. It pulls smoother with far fewer hiccups, chuffs and stumbles. Above the rpm basement the engine pulls smoothly and strongly with a seamless, ever-increasing flood of power reaching the rear tire. Only in rare instances or with sloppy throttle control does the power overwhelm traction. A moderate amount of care with the twist-grip will ensure that the majority of the boost is channeled into forward motion. We switched back-to-back with a 525 and the jump in the delivery around midrange makes it feel zippy, but the 530 ate it up in any roll-on comparison and required less thought toward throttle control or traction.
Even the 530 eventually runs out of power-at least in one gear-but there's always another gear waiting eagerly. The shifting ease and accuracy are vastly superior to the older KTM engine. The 525 wasn't bad, but the 530 is more positive with no false shifts and you barely have to think about shifting. If you're riding on the balls of your feet through rocks or stumps, often just rubbing the sole of your boot against the side of the shifter will select the next gear. But since the shifter is tucked away, we never accidentally bump-shifted the bike either up or down.
KTM claims that the entire engine and the crankshaft in particular is more rigid. The one area that the 525 wasn't totally bulletproof was in extreme high-rpm, high-performance use. The new engine should help that weakness and address a few others we barely considered. The first point is lubrication. The engine and transmission oils are separated like a Honda. The primary reason is to avoid having the inevitable clutch debris run through the engine's bearings. A sight-glass on the ignition cover allows easy monitoring of the level. We were advised to change the engine oil after five hours, but after a 10-hour, 137-mile ride that saw everything from radiator-boiling slow to all the speed the engine would pull, the oil looked virtually new when we drained it. A bolt in the clutch case is removed for determining "full" on the clutch and transmission side of the engine. Just drain, then refill until oil dribbles out.

You'd think a 530 would be...

You'd think a 530 would be too much for the woods, but it's a great tool for trees.