Was pulling off the valve cover tonight to check the valves, had it on TDC, removed the cover and then pushed the bike forward (I thought it was in neutral!) and the T disappeared from the sight hole! I don't think the cam chain moved much, if at all, I had just removed the cover, the chain and follower were still in place. Can I just turn the piston back to TDC with the cover off? Or did I screw the timing up somehow? I know this is a stupid question, but this is the first time I have dug into the bike to check the valves, and the shop manual says bike must be on TDC before removing valve cover. Help!!