ORIGINAL: Antique
Easiest method..
Take the plug wire off so you can hear the spark.
You mean remove the plug from the cylinder and reinstall it in the cap don't you?
turn the crank (CCW) slowly..when you hear the spark make a pencil line across the hub and crankcase..
Measure hub diameter, multiply by .244 for 28 degreess...put piston on TDC.
How do you find TDC? Rock and guesstimate?.
Marks should be that distance apart...
If it takes more than 5 minutes you're really slow...
Using the above method it would be easy to have the timing off by 2 degrees one way or the other.
I like using a huge printed protractor so I can easily see the degrees and attach a pointer to the cylinder with a paper or spring clip. Also using a cheap-o dial indicator and magnetic base to find TDC is so easy. Set up the indicator, rotate the crank until the piston is at tdc and zero the indicator. Rotate the crank both ways until the indicator moves .001" and mark the protractor at both locations and divide in half to find exact tdc. measure over 28 degrees CCW from that point this is where you want the spark to fire or the rcexl to stop glowing and sounding. Adjust the sensor to make it so and tighten the screws. No guessing, no that should be close, it will be exact.
You can also use the indicator to check for crankshaft runout. You might be suprised to find out what's really making your plane shake so much.
CH ignitions came with good instructions.