Undo the two nuts holding the sprocket cover on - these also hold the bar in place. Yopu'll have to ensure that the cahinbrake is OFF before you try to move the cover. This gives access to the sprocket and you'll be able to re-fit the chain around the sprocket and the bar. Before you attemp to fit the chain reset the chain tensioner - a screw that moves the bar in and out - it has a little spur that fits into a hole in the bar end. Hold the bar / chain together and replace the cover. Tighten the nuts finger tight, then lifting the tip of the bar slightly adjust the chain tension until it's correct. As a rough guide the guide links should 'snap' back into the bar groove when displaced a little. Don't overtighten - but make sure there's enough tension. Once you've got the tension tighten the nuts - again, don't overtighten.
Check tension by pulling the chain through by hand (wear gloves, or use a screwdriver shaft to push drive links!). You should be able to pull it round without too much resistance, but it shouldn't 'fly' round.
You should invert the bar every time the chain is replaced, and some recommend doing this every time the saw is properly sharpened.
If there are any burrs on the edge of the bar file them off before replacing the chain. Also check under the tip of the bar - if the chain has been run slack there may be a wear pattern there (a concavity). If it's there and it's too deep you'll need a new bar. The same goes for the other end where the chain enters the bar off the sprocket - this can become flared, and allows the chain to slip off.
wes, April 2009
