Dry Sump Lubrication

In a wet-sump engine, oil collects in the bottom of the crankcase. A dry-sump engine keeps the crankcase almost empty: a scavenge pump removes the oil and sends it to a separate tank (or a chamber in the frame or engine cases), and a pressure pump feeds it back to the bearings.

The benefits are a lower engine, steady oil supply at extreme lean angles, jumps and braking, and less power lost to oil churning. That is why many motocross and enduro four-strokes, Harley-Davidson twins and racing engines use it. Two-stroke engines lubricate the crank with oil mixed into the fuel or injected, so they don't have a dry sump in this sense.

Checking the level often has a special procedure – usually with the engine warm and the bike upright. Follow the manual, since a wrong reading can lead to overfilling or running low.