The word hydrolock strikes fear into the hearts of motorcycle owners. Some have never heard of it until their mechanic gives them the bad news and my friend it is BAD NEWS.
It is a insidious condition that happens when the bike isn't even running. The unobservant riders first clue will be a bike rattling CLUNK when the starter button is pushed. In that moment the piston will try to compress a cylinder full of liquid gasoline, and if you remember your basic physics you know liquids cannot be compressed. Something has to give and that something is the connecting rod under that piston. (Read that as Major Rebuild). It hardly seems fair.
There are clues that will help you avoid this sad event.
1 Strong odor of gasoline after the bike has set for a while;
2 Puddle of gasoline under the bike or dripping out of the airbox or carburetor.
Blow these signs off at your own peril.
You see there is a chain of failures that have to happen to cause hydolock.
First is a leaking petcock on your fuel tank. If yours bike has a vaccum petcock it can become clogged, fouled or it may have been left in the prime position. A manual petcock may have been left in the on position. This allows gasoline to leak to the carburetor filling the bowl.
Next is a clogged or partially clogged overflow this allows gasoline to overfill the carburetor.
The last thing is a stuck float or float needle. This will allow liquid gasoline to fill the cylinder instead of the mist of gas and air that your motor runs on.
These three things normally don't happen all at once, but as an example, the overflow hose gets kinked. The bike sits over the winter with gas in the float bowls and degrades and makes the needle stick. Then one day you park the bike and leave the petcock on and volia you have real trouble.
So how do You avoid this sad outcome?
1 If you have a manual petcock always shut it off when you park. A vaccum petcock shuts it's self off until it fails.
2 drain your float bowls when you put the bike up for the winter and use fuel stabilizer.
3 Be sure your overflow tube is clear and has no kinks in it.
If your bike has a puddle of gasoline under it after being parked don't try to start it.
Pull you spark plugs (take them off of the wires so they don't spark) then bump the starter. Be careful if a cylinder is full of gas it will spray out of the plug hole. This will give you a clue as to what you need to do next.
If you have a four cylinder and gas sprays out of # 2 then you know that you need to rebuild #2 carb. also check the overflow and find out what went on with the petcock.
Hope this saves you some heart ache