07FE550 with 30 hours on it (per stock speedo unit).
This engine has always made a noticeable humming or rubbing noise from the engine when under load at medium revs (quarter through half throttle) in third gear and up. This is a linear sliding type sound, that I can only see as being the piston. Is this typical of these bikes? It makes me wonder if the compression ring might be stuck. I think the engine has slightly more vibration than when I first ran it.
I did a leakdown test. With 100psi on the primary gauge, the secondary gauge was 88psi. This equates to 12% leakage. No air noise at the muffler outlet or air cleaner, just at the oil filler plug. The air was leaking through the piston rings. By the time I had assembled the pieces necessary to make the tester, the engine had cooled off to only slightly above room temperature. I have read that the test should be done on a warm engine. A warm engine would have less end gap on the rings due to temperature expansion. I'm just not sure if this would make a large difference. If the test results showed 20% or more, I would take it apart to investigate. At 12% does it need a teardown?
On to the next item: Lots of little flakes in the oil on every change (changing it every other ride, total 200km before change). The drain plug has a normal furriness with the odd tiny sliver, a few small bits (nothing recognizable as an engine part). The oil (Motul 300V 15-50) comes out dark, but does not smell or feel really beat up.
There are always a few flakes that wind up sitting on the screen, but these are the same as the ones in the oil. The flake size varies up to about 1mm square maximum. Very shiny but not magnetic. I haven't tried to measure the thickness of one, but they are very thin. I would say from 50 to 100 flakes in the pan each time. I think this quantity of flakes indicates something could require attention soon.
I'm still a little rich on the jetting, but other than the issues just mentioned, the bike seems to operate fine. Recommendations?
This engine has always made a noticeable humming or rubbing noise from the engine when under load at medium revs (quarter through half throttle) in third gear and up. This is a linear sliding type sound, that I can only see as being the piston. Is this typical of these bikes? It makes me wonder if the compression ring might be stuck. I think the engine has slightly more vibration than when I first ran it.
I did a leakdown test. With 100psi on the primary gauge, the secondary gauge was 88psi. This equates to 12% leakage. No air noise at the muffler outlet or air cleaner, just at the oil filler plug. The air was leaking through the piston rings. By the time I had assembled the pieces necessary to make the tester, the engine had cooled off to only slightly above room temperature. I have read that the test should be done on a warm engine. A warm engine would have less end gap on the rings due to temperature expansion. I'm just not sure if this would make a large difference. If the test results showed 20% or more, I would take it apart to investigate. At 12% does it need a teardown?
On to the next item: Lots of little flakes in the oil on every change (changing it every other ride, total 200km before change). The drain plug has a normal furriness with the odd tiny sliver, a few small bits (nothing recognizable as an engine part). The oil (Motul 300V 15-50) comes out dark, but does not smell or feel really beat up.
There are always a few flakes that wind up sitting on the screen, but these are the same as the ones in the oil. The flake size varies up to about 1mm square maximum. Very shiny but not magnetic. I haven't tried to measure the thickness of one, but they are very thin. I would say from 50 to 100 flakes in the pan each time. I think this quantity of flakes indicates something could require attention soon.
I'm still a little rich on the jetting, but other than the issues just mentioned, the bike seems to operate fine. Recommendations?
