I've been working on this 75 KZ400 for quite some time and finally getting close to the finish line.
This is my first project and i've pretty much gone through the whole bike. Engine has been rebuilt:
0.5mm rebore, new gaskets, pistons, rings, cam chain, cam chain tensioner, seals, valves, valve springs,
head sandblasted, etc, the whole deal.
The first time i put the engine together and after the first 5-ish starts (~5-10min) there were no leaks,
at some point the cylinder head had developed a few small leaks, like air bubbling out the head base gasket,
head o-ring and 2 small leaks from the head cover. Head and head cover both have a rubber o-ring, so i put
some silicone over the the head, but didn't on the head cover. From what i read online you're supposed to
re-torque all bolts after a few good head cycles. So, i removed the head cover, got some silicone over the
head o-ring and then torqued everything to the manual's spec.
Started and ran the engine today for a good 10 minutes, head cover no longer leaks, but i noticed bubbling
on the right side of the cylinder head gasket. Before i re-torqued the head again, there was a bubbling on
the left side of the cylinder head gasket (near the front stud), which is gone now.
At this point i'm not sure what i'm doing wrong. I haven't checked the head surface for warpage, could this be
the case? The engine runs fine, revs up great, but i'm at the loss of what the leakage issue might be.
Any ideas or suggestions are highly appreciated. Thanks!
This is my first project and i've pretty much gone through the whole bike. Engine has been rebuilt:
0.5mm rebore, new gaskets, pistons, rings, cam chain, cam chain tensioner, seals, valves, valve springs,
head sandblasted, etc, the whole deal.
The first time i put the engine together and after the first 5-ish starts (~5-10min) there were no leaks,
at some point the cylinder head had developed a few small leaks, like air bubbling out the head base gasket,
head o-ring and 2 small leaks from the head cover. Head and head cover both have a rubber o-ring, so i put
some silicone over the the head, but didn't on the head cover. From what i read online you're supposed to
re-torque all bolts after a few good head cycles. So, i removed the head cover, got some silicone over the
head o-ring and then torqued everything to the manual's spec.
Started and ran the engine today for a good 10 minutes, head cover no longer leaks, but i noticed bubbling
on the right side of the cylinder head gasket. Before i re-torqued the head again, there was a bubbling on
the left side of the cylinder head gasket (near the front stud), which is gone now.
At this point i'm not sure what i'm doing wrong. I haven't checked the head surface for warpage, could this be
the case? The engine runs fine, revs up great, but i'm at the loss of what the leakage issue might be.
Any ideas or suggestions are highly appreciated. Thanks!