This question is not pertinent to the GS series motorcycles covered on this forum but it does relate to a slightly younger GS bike. Hope it's ok to post this question here.
Picked up a 1993 Suzuki Katana GSXF 750 project some time ago and have just recently started digging into it to find the issue(s). The bike had not been used for quite a while and I was told there was a compression issue in #3 and possibly more cylinders.
Once I started getting into it I took compression readings myself and the results were horrible - 90/95/30/50. Valve adjustment produced a slight improvement in compression numbers but it was obvious head and barrels would need to come off for proper inspection.
This is what was found.......
Top piston rings on #3 and #4 broke and caused massive ring land failure. Bits of ring found embedded into head combustion chamber domes adjacent to exhaust valves. Piston crowns around same area showing identical "punctures" caused by piston rings debris propelled withing cylinder while engine was running. Cylinder walls on cylinders 3 and 4 are also gouged along full length of stroke.
Quite a coincidence 2 pistons would fail the same way at the same time. Both piston #3 and #4 have identical damage. Pistons 1 and 2 don't appear to have any issues at all. Perhaps a previous overheating episode on this engine caused the rings to lose their temper and consequently failed due to high rpm at a later time?? What do you folks think? Lack of oil? Engine laid up for a long period of time (years) and rings partially seized up in their grooves and broke off when the engine was started?
See attached picture.
Picked up a 1993 Suzuki Katana GSXF 750 project some time ago and have just recently started digging into it to find the issue(s). The bike had not been used for quite a while and I was told there was a compression issue in #3 and possibly more cylinders.
Once I started getting into it I took compression readings myself and the results were horrible - 90/95/30/50. Valve adjustment produced a slight improvement in compression numbers but it was obvious head and barrels would need to come off for proper inspection.
This is what was found.......
Top piston rings on #3 and #4 broke and caused massive ring land failure. Bits of ring found embedded into head combustion chamber domes adjacent to exhaust valves. Piston crowns around same area showing identical "punctures" caused by piston rings debris propelled withing cylinder while engine was running. Cylinder walls on cylinders 3 and 4 are also gouged along full length of stroke.
Quite a coincidence 2 pistons would fail the same way at the same time. Both piston #3 and #4 have identical damage. Pistons 1 and 2 don't appear to have any issues at all. Perhaps a previous overheating episode on this engine caused the rings to lose their temper and consequently failed due to high rpm at a later time?? What do you folks think? Lack of oil? Engine laid up for a long period of time (years) and rings partially seized up in their grooves and broke off when the engine was started?
See attached picture.
Last edited:
