Where to Start-1979 750f Super Sport? Carb/Compression or both?
- Thread starter Hastings
- Start date
mrtwowheel
CB750 Enthusiast
Inches, millimeters 
Connella08
CB750 Member
im not convinced that .001" difference in valve lash is going to cause cylinder 2 to not fire, especially if its on the loose side. he posted valve lash numbers, but was a compression test conducted? I feel like valve lash was identified as the problem with no real information to point to it. if compression numbers were low, then i'd start looking at valve clearances. this sounds like fuel or could even still be ignition.
when you did your first spark test, was the engine cold or hot? if cold, the heat soaking into the electrical components (such as pickup coil and ignition coils) could be causing the ohm reading to sway out of spec.
first things first, do a compression test.
when you did your first spark test, was the engine cold or hot? if cold, the heat soaking into the electrical components (such as pickup coil and ignition coils) could be causing the ohm reading to sway out of spec.
first things first, do a compression test.
mrtwowheel
CB750 Enthusiast
Reread your first post. Yes, do a compression test. If the cylinders even have 150 they should run and will probably get better after it runs for a while. You can't avoid the carbs, fully clean them, just spraying them is never enough.