Andy's been here long enough to have a good grasp of the search function, so I'll cut him some slack and give an answer.
Harbor freight meter? The little red one right? It'll work fine, I use one all the time.
Take the spark plug caps off the wires (they unscrew) if they're ancient you may want to replace them later, any bike shop has them (5K ohms rating, choose you favorite angle)
Clip back the plug wires a quarter inch to expose fresh wire and to get rid of the 1/4" of oxidized wire that always seems to form at the plug ends.
Make sure the connectors on the small wires on the coils are clean too, there's a recent thread about cleaning connectors.
Set your meter to measure resistance, a range somewhere in the middle of the available selections will do, touch the two test leads together and notice the meter reads close to zero.
Measure across the small wires of one coil, write it down, measure across the small wires of the other coil and write it down for comparison.
Now measure across the plug leads on one coil, write it down, then measure across the plug wires from the other coil and write that down for comparison.
You may want to adjust the range your meter is set on so that you have one place to the right of the decimal point showing but it's not a requirement.
if you have a pair of clean screwdrivers and a helper, you can easily measure the resistance of your plug caps by inserting the screwdrivers into each end of a cap and having your helper touch the meter leads to the screwdriver shafts. The caps should measure 5000 ohms or 5K ohms but that resistance will rise over time and will give you a weaker spark, one of mine on my 750K3 measured 18K and and 3 were over 10K, the 4Th was like 6 or 7K if I remember correctly.
New caps are cheap, NGK caps can be found at most any motorcycle shop for a few bucks each,
-Alan
