The complete process is found in the Red Technical Sticky's
located at the top of the Iron Head Forum's opening page.
I have copied the relevant section on "generator polarizing"
here below for you.
The entire section is located here as well.
10. Polarizing the Generator - The Complete Story
Contributed by Fe Head and carmine73
1. with the gen on the bench
[i] jumper the gen A to batt +ve
[ii] momentarily jumper from gen F to batt -ve
Note: This can be done the other way around,
[i] jumper gen F to the -ve batt
[ii] momentarily jumper gen A to batt +ve
2. with the gen on the bike, wires not connected
[i] jumper from gen F to a good ground
[ii] momentarily jumper from gen A to batt +ve
Note: This technique is preferred over #3 because the good ground is better than relying on grounding the F thru the reg.
Note: As with #1 this can be done the other way around.
3. with the gen on the bike, all wires connected
[i] momentarily jumper gen A to batt +ve
Note: This is technically the same as techniques #1 and #2 as the F is grounded thru the reg.
4. For bikes with a mechanical reg [1959 to 1977]
Momentarily jumper between BAT and GEN on the reg.
Note: this is technically the same as all of the other techniques as BAT is connected to batt +ve and GEN is connected to gen A.
5. For bikes with a Cycle Electric Generator/Regulator
Contributed by FourCams
All the best as you work through the Sticky's.