Coolant leak

You see a colored puddle (pink, green, blue depending on the fluid type) under the bike, notice a distinctive sweet smell, and the coolant level drops. This needs addressing, since fluid loss leads to overheating, which can damage the engine. The first step is to determine whether the leak is visible and can be located, or whether the level drops with no leak apparent (a more concerning case). Causes of a visible leak: a cracked/porous hose or a loose clamp (common and accessible), a radiator or reservoir cap that no longer holds pressure (fluid overflows — an inexpensive part), a punctured radiator (impact, corrosion, often at the bottom), or a worn water pump seal (fluid drips from the weep hole under the engine — a more technical job). If the level drops WITHOUT a visible leak, and the bike overheats or gives off white smoke, suspect the head gasket (the fluid is going into the combustion). You tell them apart by looking for the puddle and identifying its source. Urgency threshold: don't ride with a leaking circuit and a low level — overheating looms, and an overheating engine can seize or crack. Major safety point: NEVER open the radiator cap on a hot engine, the pressurized fluid sprays out and causes severe burns — always work with a cold engine. If the leak is significant or the level is dropping fast, better to stop and get it repaired than risk the engine. The color and location of the puddle are your best clues: note them before doing anything, and clean the area to spot where fresh fluid is seeping from once you start diagnosing.