1st question: the service manual spec says 100psi is the service limit but is that with or without the squirt of oil?
Bike was sitting for about a week since I last started it so I think that was enough time for the oil to completely drain into the crankcase. I also measured the compression cold without starting it and warming things up. So I would guess that when the engine is actually running the pressure was closer to the 150 psi oiled than the 100 psi dry, right? Meaning the rings are okay?
The weird thing was cylinder 4 (the right most). When I pulled this cylinders original spark plug it was very sooty with carbon, the other three looked fine. I changed the plugs about 70 miles ago, including two 30 mile highway runs at around 70+ mph. This brand new plug in the 4th cylinder was again pretty sooty with carbon when I pulled it to do the compression test though not as much as the original plug. When I ran the test, it only showed about 60psi. Squirted the oil and it had almost no effect, again about 60 psi.
Here's the odd thing: I realized that I had been measuring the compression without holding the throttle wide open (including for the other three cylinders' 100psi dry to 150psi with oil measurements, all with throttle closed). When I measured the compression on this 4th cylinder again with the throttle wide open, then it came up to 150psi like the other cylinders (this is after I squirted in the oil).
So is this telling me that the sooty carbon on the plugs and the low compression is due to the 4th carb not being synced or something like that? As opposed to being the rings? between the sooty spark plug and the odd compression behavior, I feel like there's something specific going on with number 4, I just have no idea what.
Thanks in advance for any help!
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