how do i check compression
- Thread starter bonafidehussler
- Start date
You're going to want to use a good compression guage with a threaded end approximately the same length as your spark plug threads. It needs to have a scrader valve (like in your valve stems on your tires) in the threaded end. You will screw this into your spark plug hole and proceed to kick the bike over holding the throttle wide open untill the guage stops moving. This is best done with the machine warmed up to indicate a proper seal of the rings to the bore. If you have just rebuilt the engine the oil you applied for assembly will affect the first couple of readings showing higher than a dry bore. Guages with shorter threaded ends or without the scrader valve in the end will indicate a lower reading than you acctually have. The compression test should only be used as a basis for cylinder condition and compared to previous tests. It is not a replacement for figuring compression ratio to determine fuel octane needs.
