1984 XT600 Engine Disassembly HALTED

[John1189]

I'm in the process of removing the top end cover of the engine on my 1984 XT 600.

I began to hear a knocking sound with 500 miles left on my cross country trip. The motorcycle had been performing with less than peak power for the better part of a trip lasting several thousand miles. I checked and cleaned and rechecked and cleaned the carb a few times, never to much gain. I finally took notice of the shape of the 30 year old boots. They were showing cracks, potentially letting unfiltered air into the fuel/air mix.

Now that I am getting into the engine, I can see that the right-side intake valve is caked in crud. Now is where I do not know how to proceed: to take off the top end cover, my Clymer's manual says to find top dead center. Well, every time I kickstart the motor I'm nearly positive I'm finding top dead center; this is one of the basics of starting a kickstart motorcycle, I believe. According to the manual, the top dead center is found by aligning the inscribed " lT " on the rotor assembly in the center of the quarter-size window at the top of the left-side crankcase cover. When this is aligned, the rocker arms will have "free play" allowing them to be wiggled, it says. I am unable to align the marking and as far as I can tell, at no point is there "free play". As I approach the inscribed " lT " when turning the rotor by hand, the rotor rotates freely, or slightly falls, just past this mark. This position is what I would say is the top dead center by feel alone. I'm confused and I hope that my description of the problem is not confusing to you, the reader. Thanks in advance to those who read.