Motorcycle weight is expressed in three ways: gross vehicle weight rating (GVWR), dry weight and wet weight. GVWR is the maximum total weight of the motorcycle including all consumables, the rider, any passenger, and any cargo. It is generally well-understood and standardized, being defined by law and overseen by agencies such as the US Department of Transportation. In contrast, wet and dry weight are unstandardized measurements that refer to the weight of a the motorcycle without rider, passengers or cargo, and either with (wet) or without (dry) a varying set of fluids such as fuel or lubricants, and the battery.
Wet and dry weight are often used to make comparisons between different motorcycles, because all else being equal, a lighter motorcycle will generally perform and handle better better than a heavier one.
The difference between GVWR and wet weight is how much the motorcycle can safely carry, including the rider, and any passenger and their cargo and other accessories. This is especially of interest in touring motorcycles because the greater the difference between GVWR and wet weight, the more gear and supplies may be brought.
There is no standardized way to test the dry weight of a motorcycle. Inconsistencies will almost always be found between a motorcycle manufacturer's published dry weight and motorcycle press and media outlet's published dry weight. This is due to different testing techniques, differences in what is being excluded, and a lack of defining how testing was conducted by the organization doing the testing. A battery is typically excluded from dry weight by manufacturers but not always by media outlets. Some press and media outlets just exclude fuel to define their dry weight. For a typical sport bike, the difference between wet weight and manufacturer claimed dry weight is around 70lbs. This difference includes around 30lbs of gasoline, 7lbs of engine oil, 7lbs of coolant, and 9lbs of battery. These weights are even larger for bigger motorcycles with higher capacities, and attempting to compare the dry weights of air-cooled versus water cooled motorcycles can be misleading.
Hydraulic fluid is not strictly speaking a lubricant, but it is a liquid that might be excluded during shipping. Thus it is not safe to assume that it is either included or excluded. Hydraulic fluid might only be found on a particular bike's front brake with a single line, or could be used on dual front brakes with two lines and one reservoir, plus maybe a rear brake with a reservoir, and also maybe in a hydraulic clutch with its own reservoir, adding a few ounces to a pound or two of uncertainty.
Beginning in 2009, the four major Japanese manufacturers, and BMW, began publishing the wet weight rather than dry, usually providing some explanation for what this means. Honda describes it as curb weight and says this means the bike is "ready to ride." Others say all fluids are included and the fuel tank is at least 90% full.
The wet weight of a motorcycle includes, but is not limited to fuel, engine oil, coolant, brake fluid, and battery.
There is no global standardized way to test the wet weight of a motorcycle. In the EU, Council Directive 93/93/EEC specifies wet weight as "mass in running order", which includes all equipment normally fitted to a bike such as windscreen, tool kit and at least 90% of its fuel capacity. Motorcycle manufacturers will rarely publish wet weight measurements and inconsistencies will almost always be found between different motorcycle press and media outlets. This is due to different testing techniques, differences in what is being included, and by the organization doing the testing omitting an explanation of how they weighed the motorcycle.
Cycle World has published wet weights with all consumables onboard, but only 1/2 a tank of fuel, while Honda has recently published specification tables that use the typically automotive-oriented term curb weight, and stated that it included full fluid levels and the bike was "ready to ride."
Gross vehicle weight rating
A gross vehicle weight rating (GVWR) is the maximum allowable total weight of a road vehicle or trailer when loaded - i.e including the weight of the vehicle itself plus fuel, passengers, cargo, and trailer tongue weight.
The difference between gross weight and curb weight is the total passenger and cargo weight capacity of the vehicle. For example, a pickup truck with a curb weight of 4500lbs might have a cargo capacity of 2000lbs, meaning it can have a gross weight of 6500lbs when fully loaded.