What's that? You didn't know the XT550 has magneto oil? Neither did I. This is how I found out. I've been trying to track down a problem with my XT550 and I'm bald, so now I'm pulling my eye brows out. The bike runs, sometimes it's a little hard to start, but it runs. Now it runs consistently like it's not firing on all cylinders for the first 15 minutes. Being a single this makes it even more interesting. It pops on decelleration. Above 1/2 throttle, it just doesn't want to go and will actually slow down. As it starts to "wake up", it surges, backs off, surges, backs off, surges for a bit and then out of now where, full power! It will run normal from then on as long as it's warm. It will restart and be normal. Let it cool off and it goes back to it's groggy state. This started about a week ago. The only thing that has been done to it is a valve adjustment. The day I picked it up, it was fine. Then it rained for a week, and I accidentally left the gas on. When it ran this way, cleaned the carb, thinking it was running lean due to varnish. Since then, I've pulled the carb joint boots, inspected them, replaced the o-ring behind the boots and replaced Yamaha's stock clamps with ordinary hose clamps. I've sprayed it with carb cleaner and there's no change in idle, so I no longer suspect a carb leak anywhere. I've replaced the spark plug. The PO had taped up the plug wire and boot with electrical tape. I removed it, inspected the boot and wire. I have no idea why he covered it in electrical tape, but I re-covered it in electrical tape again. I've pulled all the panels, scrubbed every ground, even though they look OK with a wire brush. I've cleaned every electrical contact I could find that was related to the CDI, magneto, spark plug coil. None of this helped. So, I decided I should check the timing. I pull the left side engine cover to look at the magneto, since the tiny hole yamaha provides for checking the timing doesn't let you see much. Plus, I broke my screw driver trying to take it off, so I wanted to see if there was a reason it broke a 1/2" wide flat head screw driver. I figure this way, I can see what timing marks are available. The bottom two cover bolts are oily, but this is no surprise. I've had several bikes that get a bit of oil in this cavity. I crack the cover, more oil comes out, a lot more. I grab and oil pan too late and about a 1/2 quart or so of oil drains out. I think to myself "$h*t, this is one of the bikes that has the clutch on the left. Oh, well. I got in this deep, I may as well take a look at the clutch." As I pull the cover off, there's the flywheel and stator covered in oil. Great. Well, it is a 27 year old bike... So I examine the available markings on the flywheel, remove the timing cap and reinstall. Then I fire up the bike and in no time at all, I see how all this oil got in there, it's spitting oil out the timing light hole! Worse, it covered my girlfriend's cars' rear fender and tire with oil. So I can't check the timing. There is a steady pulsing air/oil stream coming out of this hole. So, I need some help here. First, can you replace this crank seal without splitting the cases? (please say yes, please say yes). Second, am I going to need a flywheel puller? Third, this thing is huge! Is it possible to use a stator and flywheel and CDI pick-up from a different bike on the XT550? Most importantly, do you think this could be the source of my runs like crap problem?