Can a crank seal leak on a stock engine?
Since most ignition covers are airtight themselves, an ignition-side crank seal leak can go on unnoticed for a long time on a stock output engine. If you find an oil residue in the ignition compartment when removing your ignition cover, there’s a very good chance that your front seal is bad.
What should I do if my fuel valve is leaking?
First, remove your fuel supply line from the petcock. Then unplug the vacuum line at the back of the fuel valve. When the bike is not running, the fuel valve should only supply fuel in the prime (PRI) position. When in the on or reserve positions no fuel should be supplied.
What happens if you have a leaking gas valve?
A leaking gas valve can do more than just waste gasoline. If a leaking gas valve or carb float needle cause gasoline to fill the engine crankcase and you attempt to run the bike, the fuel is then pumped through the system washing oil from vital areas such as bearings. This situation is called gas washing the engine.
Can a small air leak cause a seized piston?
A small “air leak” at a crank seal or an intake gasket will cause the usually perfect fuel/air mixture in the crankcase to become slightly lean…sometimes very lean. This lean mixture can quickly result in a seized piston. Air leaks are, by far, the number one cause of vintage engine piston seizures.
Since most ignition covers are airtight themselves, an ignition-side crank seal leak can go on unnoticed for a long time on a stock output engine. If you find an oil residue in the ignition compartment when removing your ignition cover, there’s a very good chance that your front seal is bad.
First, remove your fuel supply line from the petcock. Then unplug the vacuum line at the back of the fuel valve. When the bike is not running, the fuel valve should only supply fuel in the prime (PRI) position. When in the on or reserve positions no fuel should be supplied.
A leaking gas valve can do more than just waste gasoline. If a leaking gas valve or carb float needle cause gasoline to fill the engine crankcase and you attempt to run the bike, the fuel is then pumped through the system washing oil from vital areas such as bearings. This situation is called gas washing the engine.
What to do if your gas petcock is leaking?
Many mechanical gas petcocks can be rebuilt with a repair kit that contains replacement o-rings, springs, rubber diaphragms, etc. These small parts are available from OEM dealers or aftermarket sources. The older your bike is, the more likely it is that these parts have been discontinued by the manufacturer.