Camchain tension.

The HBOL for my SO XJ600 (non diversion) says that I should only adjust the
camchain when the engine is at TDC. This involves removing the alternator
to turn the engine over by hand. No big deal except usually this causes the
gasket for the alternator to stick to the casing then rip. I then have to
make up a new one which sometimes doesn't fit. So what could be a thirty
second job turns into a two hour swear-athon.

So my question is, does the engine need to be at TDC? I can't get my head
around as to why this would matter. Surely the slack in the camchain is the
same regardless of the position of the engine or cams/

 

I assume the gasket is paper? Greasing it on fitting makes for clean
removal next time.

Or go mad and *buy* a replacement before you need to adjust camchain.
Paper gaskets don't tend to be that expensive - even the Japanese ones.

 

The engine rottates anti-clockwise, if seen from the left. So turning
the engine over by the alternator works by pulling 'down' on the forward
(exhaust) run of the camchain.

This means that the front run is nice and taut, and all the slack is
gathered at the rear, since it's not under any load. That slack is then
gathered by by the camchain tension action.

 

Why don't you just pop a spark plug out and use your imagination to
think of a way to tell when the engine is at TDC?