To use the meter to measure amps, plug the black lead into the hole marked COM or GND or NEG, plug the red lead into the hole marked 10A, 20A or similar then select the 10 or 20A range on the dial. For low current measurements move the red lead only to hole marked mA or similar, keep black in COM and move the dial to the appropriate range.
First confirm the meter is working by doing your exact same test but with the ignition turned on. Make sure you don't press the start button! Your meter should read anywhere from bugger all to about 10A, depending on how many lights etc you have turned on. Turning on more lights will up the current. If your meter does not register this there is probably something wrong with the meter (see my post above that mentions testing a voltage with meter set up for current) and there is no point continuing 'till you have a working meter.
If your meter does work OK, but you still can't measure any current with the ignition switched off, then the fault is definitely not with the bike flattening the battery when parked with the ignition off.
Really the speedo only needs to draw poofteenths of a milliamp when turned off and your meter might not even register this. It must be the battery itself as others have mentioned and it probably has a cell or two coming to bits inside. It would need to be replaced then monitor how it goes.
At least you will have proved the problem, not just thrown shït at it till it worked!
PS. TUTS- Why not? Never heard anyone who has done it complain!! :hang: