Bikes end up under water for two reasons: floods and tipovers in streams. If yours was thoroughly submerged (like days in a flooded basement) don’t even try to start it; it'll need a full disassembly. If it’s underwater briefly, there’s hope.
If you’re the one riding and you know the bike’s going down, flick off the kill switch before it goes completely under. If the engine is running, you risk bending the connecting rod, since the water in the cylinder can’t be compressed.
Get the bike onto dry ground, and remove the air cleaner and spark plug. Drain the airbox and exhaust pipe. Lay the bike over on its side if you have to; with a light two-stroke trail bike you can even turn the whole thing upside down.
Put the bike in gear, lift the rear wheel off the ground, and give it a spin. The engine will turn over slowly and pump any water in the cylinder out the plug hole. If your bike has a carburetor, remove the float bowl or the bowl’s drain screw, drain the gas, and reinstall.
Reinstall the spark plug, dry the contacts, wring the air cleaner out and reinstall, and try to start the bike. With luck, it should run fine. As soon as possible, change the oil in the engine and gearbox (and final drive if your bike has a shaft). And don’t let it happen again!
Bikes end up under water for two reasons: floods and tipovers in streams. If yours was thoroughly submerged (like days in a flooded basement) don’t even try to start it; it'll need a full disassembly. If it’s underwater briefly, there’s hope.
If you’re the one riding and you know the bike’s going down, flick off the kill switch before it goes completely under. If the engine is running, you risk bending the connecting rod, since the water in the cylinder can’t be compressed.
Get the bike onto dry ground, and remove the air cleaner and spark plug. Drain the airbox and exhaust pipe. Lay the bike over on its side if you have to; with a light two-stroke trail bike you can even turn the whole thing upside down.
Put the bike in gear, lift the rear wheel off the ground, and give it a spin. The engine will turn over slowly and pump any water in the cylinder out the plug hole. If your bike has a carburetor, remove the float bowl or the bowl’s drain screw, drain the gas, and reinstall.
Reinstall the spark plug, dry the contacts, wring the air cleaner out and reinstall, and try to start the bike. With luck, it should run fine. As soon as possible, change the oil in the engine and gearbox (and final drive if your bike has a shaft). And don’t let it happen again!