Well you shouldn't really just remove one cap as there is a potential for snapping the cam if the lobes on #1 are holding the valve open, if it was me i'd put #1 to TDC, inlet and exhaust valves closed and go for it but now that i've said i'd do it you'll probably break yours and i'll be a cunt so to do it properly you should losen all caps evenly and re-thighten evenly to avoid a snapped camshaft!