A motor analyser is a useful tool, however it's not essential. If you're concerned about the price then I'd pass on it. You can find no-load current with a multimeter easily enough. If you need the timing/kV comparison readings to choose between different motors, the expense of the motors is likely to dwarf the cost of the analyser. If you just want to check your current motor, you may be able to borrow an analyser from someone at the track.