thats the exhaust stroke, compression would be one more revolution, with both valves closed. however you need to be certain if you are at the top of No 1, not just "believe", you can't kind of guess on these matters, you could also check and see where the ball is on the flywheel. It won't be exactly crankshaft TDC, as the ball is for ignition timing, but it should be in the very very near neighborhood. If your gears are new, there is a possibility the keyways in your gears are cut incorrectly, a very, very slim possibility, like almost inconceivable, but that sort of thing has been known to happen.
