The cleanest motorcycle is a motorcycle that you never ride. Oil, fresh pavement, coolant, and dirt cling to an experienced motorcycle, but a film of dirt masks leaking gaskets and weeping oil seals. A monthly wash will not only keep the paint shiny but will also help you catch any problem with your bike before it becomes a problem.
Motorcycles are durable and built to withstand bad weather and bad conditions, but for your own sake, avoid splashing water in some places.
Gas tanks
 Gas tanks are vented to the atmosphere to not leave a low pressure during fuel discharge, which can eventually impede gas flow, known as vapour lock. For this reason, avoid spraying water directly on or around the gas fill cap to prevent water from seeping into the gas tank.
Radiators
Radiators are known as heat exchangers because they dissipate hot engine coolant by exposing it to cooler ambient air through aluminum fins. These fins are brittle and can flex if water is applied directly to them, which can cause the engine to run abnormally hot. If you need to clean the radiator, use pliers to pry insects and other debris from the fins.
Motorcycle chain
Finally, your motorcycle chain is covered in oil, so spraying water on it won’t do you much good, and then you will waste your time, so do yourself a favor and clean the chain thoroughly when you’re done cleaning the rest of the chain.
Before getting the bike wet:
- Check the fork seals for traces of oil that indicate the seals are leaking.
- Check the cylinder head (s) to make sure the valve cover gasket has not broken, then give the engine one time to look for oil leaks.
- If you notice oil, look for the highest point where you can find a leak.
Gravity will cause the oil to drip, and the wind will blow the oil everywhere, making it difficult to diagnose the source of the leak.