corbshere, your 72 has a points ignition, not the TCI. On your bike power from the battery flows to the key switch, engine stop switch to the coils. At the coils on the red/white wire should be battery voltage. If not you need to trace back along the red/white wire and find where the voltage is. Most probably a dirty switch. Most keyswitches can be taken apart and the contacts cleaned. The engine stop switch too. If you have power at the coils, check your points. Are they clean and gapped right?
If they are ok then you need to check the coils. The primary side, The two small wires, should read 3.9 ohms + or - 10%, infinity to ground, The mount tabs.
On the secondary side, the spark plug wire. It should read 8,000 ohms = or - 10% from where the plug wire hooks in to the mount tabs. Infinity to the primary side.
If you test from plug cap to plug cap it will be closer to 15,000 ohms.
If a coil reads very different from these specs then it probably is bad.
My guess would be points. If they are dirty or stuck shut or open, you won't get spark.
A question, Do you have a repair manual? If not you should get one. The 70 to 79 bikes all used points. So any year manual from 70 to 79 will tell you the procedure for setting the points.
One thing about the tune up procedures, they should be done in a certain order.
Cam chain tension
Valve adjustment
Points gap
Points timing
biker.net has downloadable manuals. They don't have every year but as I said any year from 70 to 79 will give you what you need to know.
Leo
