Two-Stroke Oils

XLMOTO: Two-Stroke Oils

A 2 stroke motorcycle engine sucks in fuel, compresses it, and detonates. It then blows out exhaust gasses every time the piston completes a crank circuit. In other words, every rotation of the piston is a power stroke. This action gives the 2 stroke engine its addictive instantaneous blast, and size for size pushes out more power than a 4 stroke engine. Without valve gear or a sump, 2 stroke engines are light. So in the past, almost every motorcycle manufacturer had a range of 2 stroke dirt bikes in their line-up. One of the other main differences that separate 2 from 4 stroke engines is that the former needs a set amount of oil mixed in with the fuel. A typical mix ratio for 2 stroke motorcycle engines is 40-1. This figure relates to one part oil to 40 parts gasoline.

Two-Stroke Oil’s Tough Job

Two-stroke engines don’t keep any oil in the crankcases in the same way as 4 stroke engines, so this means that 2 stoke oil must do a lot of work. The small amount of oil mixed with the fuel has to lubricate the piston, rings, cylinder bore and crankshaft. Two-stroke motorcycle oil needs just the right amount of viscosity to make it mix readily with the gasoline yet provide enough protection for the moving parts. The only other oil used in a 2 stroke engine is in the transmission. This sealed-off area of the engine needs oil to lubricate the clutch and gearbox. Although environmental laws signalled the end of large bore 2 stroke street bikes, don’t be too sad at their passing, as manufacturers haven’t entirely given up on the concept. Dirt bikers the world over hooked on the adrenaline rush of explosive 2 stroke power can still buy 2 stroke dirt bikes. Thanks to fuel injection closely monitoring the combustion process, 2 strokes run a lot cleaner than their forebears. Features such as oil injection also do away with manually mixing 2 stroke oil with gasoline as the oil is stored in an onboard reservoir.

Accessories for Handling 2 Stroke Motorcycle Oil

Disposable Gloves

When handling 2 stroke engine oil, it’s always good to use disposable gloves. You may not notice any minor cuts or abrasions on your hands but frequent contact with dirty or clean oil can cause skin rashes and infect cuts. A box of disposable vinyl gloves is a simple and inexpensive solution.

Measurement Flask

For those with vintage road bikes or more modern dirt bikes, precise ratios of fuel and oil are the lifeblood of an engine. A measuring flask marked in fluid units and mix ratios is a must-have piece of kit.