Mopeds, when properly maintained and ridden carefully, have very few problems running in the winter. Some key adjustments to a moped's engine, coupled with good maintenance and a little forethought, can make winter riding a real possibility.

Air/Fuel Ratio

If your moped has problems starting in cold weather, your air/fuel ratio needs adjustment. Many mopeds have very simple carburetors; these can be adjusted for colder weather by making the air/fuel ratio richer than normal. This compensates for air's higher density at low temperatures.

Spark Plugs

Changing a moped's spark plug out for a hotter plug can also help cold weather starting and general performance and efficiency. Finding the right plug is often as simple as taking your bike's current plug to the auto parts store and asking for a replacement that's one heat range hotter.

Other Considerations

Consult the bike's owner's manual for information on the recommended type and quantity of engine oil. If your bike is a two-stroke, there are probably no extra instructions, but if you own a four-stroke moped or scooter, a different weight or quantity of oil may be specified for optimal cold weather performance.

Tires

Air increases in density as the weather turns cold. This means that for a fixed volume of air, the pressure decreases with decreasing temperature as well, according to the Ideal Gas Law. Your moped will handle and stop much more safely and smoothly with properly inflated tires, so check your tire pressure before riding.

Safety

If you choose to ride in cold weather, be extra vigilant in traffic, since cars don't usually look for two-wheeled vehicles in cold weather. Watch for icy or slick roads, and keep an eye out for salt and gravel. Be smart and keep your machine in working order.

Source:

UW: Caution