01-07-14, 08:29 PM
Fairly low for 2 star fuel. Compression pressure on a z1 should be 130-160psi.
Assuming the valve clearances are set right:
If its been stood it could just be gummed up rings or even corrosion on the valve seats if it wasn't laid up properly. Take the plugs out and drop a thimble full of diesel down the bores. Just enough to cover the top of the piston. leave it overnight it will act like penetrating oil and hopefully break free the rings if they are stuck. Make sure you spin over the engine to get any left over diesel out before refitting any of the spark plugs. Bare in mind that most of the diesel will end up in the sump so you either do an oil change afterwards or on the cheap just drain the oil into a clean container the pour it back in afterwards.
Run it for a few days at various loads and speeds then do another comp test to see if there's an improvement.
Assuming the valve clearances are set right:
If its been stood it could just be gummed up rings or even corrosion on the valve seats if it wasn't laid up properly. Take the plugs out and drop a thimble full of diesel down the bores. Just enough to cover the top of the piston. leave it overnight it will act like penetrating oil and hopefully break free the rings if they are stuck. Make sure you spin over the engine to get any left over diesel out before refitting any of the spark plugs. Bare in mind that most of the diesel will end up in the sump so you either do an oil change afterwards or on the cheap just drain the oil into a clean container the pour it back in afterwards.
Run it for a few days at various loads and speeds then do another comp test to see if there's an improvement.