I assume the window is still in place...
If so, it needs to come out.
Not too difficult...
Need to remove the engine cover, spring and hinges... which could come off with the cover, if I remember correctly.
Then there is a long clip and two, or a few screws or bolts that hold the window up. Remove these, squirt some soapy water around the gasket and glass, inside and out... then massage the window down and out. Be patient and careful, it'll come... then the gasket lifts out of the channel in its entirety.
(I ran around a few years without the glass and the gasket glued in just for fun... Once the fumes and tappet noise were remedied... the heat and engine sound became a bit tiring after awhile. Do take it around the block though...)