The KLX's 111cc four-stroke single is stronger-better for hauling 150-pound-plus loads-thanks to revised cam timing, a freer-flowing exhaust and reduced piston-ring tension. You can kick-start it if you want, but it's a lot easier to push the button on the reshaped handlebar and let the battery expend its energy. An additional gear in the transmission brings the count to four, allowing riders to make better use of the KLX's extra oomph. More power requires more control, so stiffer springs and firmer damping rates have been implemented at both ends to help resist bottoming and sharpen handling. A centrifugal clutch keeps things simple for less experienced riders, and a revamped shift drum makes gear changes even smoother.

For more advanced riders, the KLX110L ups the ante with a heavy-duty manual clutch that lets you ring every drop of power out of the high-revving engine. At 28.7 inches, the L-model's seat is nearly 2 inches higher than the standard KLX, opening up the ergonomics for larger riders. Part of that height comes from a longer fork and shock that add an inch of suspension travel, the better to handle rougher terrain and more aggressive riding.

To introduce the 2010 KLX110s, Kawasaki opted to throw the normal Power Point presentation out the window and let the bikes speak for themselves. Any bashfulness we felt about riding a children's bike vanished during our first laps on the little thrashers. Hucking the bike over jumps and pushing feet-up, two-wheeled slides had all the riders grinning from ear to ear. Shorter final-drive gearing and slick shifting action made for surprisingly rapid acceleration-and wheelies!-and the reshaped shift lever is much easier for adult-sized feet to operate.

The updated suspension is a big improvement over that of the previous model. The 2010 KLX felt taut railing berms and only bottomed-out on the ugliest of landings. Bigger, beefier, tapered roller bearings replace the loose balls in the steerer tube's lower race, a strategic update aimed at increasing durability and reducing maintenance.

Both models put on 18 pounds for the new year, but that's a small price to pay for the convenience of electric start and more abuse-friendly components. No matter which model you choose, the KLXs have the versatility to entertain the entire family. Just make sure to share the seat time with the kids...