View Full Version : HOW-TO: Bringing a Triumph Generator back to life

10-04-2010, 6:05 PM
Ok. So in an effort to prove that I have some motorbikes and not just a flair for hanging out in the junk pile, I'm doing a tech article that can save you time, trouble, and money.

Sorting out the mother effing Triumph generator!

This particular bike is a '59. You can test your generator's output by taking the 2 leads that go to the voltage regulator and twisting them together and touching them to the positive lead of a volt meter. Make sure you ground the negative lead to the bike. At idle, these things don't put out a lot of voltage, so rack up 3,000 rpm's and see what's good.

In my case, no voltage at all. So I open the cap and see what's going on in there.

A nasty mess that in no way could have made power is what I found.


Pull that bitch out, and place it on the bench.


Might as well take it all apart so you can make sure everything's in order.




This is the Field Coil. It has two leads coming out of it. You need to take a meter to that and make sure you're not reading more than 3.3 ohms. I'm reading 3.0, so I'm gonna allow it.

This doesn't mean the armature is good though. That also may be the reason someone was hacking up this genny before me. But you have to eliminate all the factors by doing this the right way to determine why you're not making power



My wires were bullshit looking so I used 2 different color wires to keep track of them. The polarity matters when it comes time for reassembly so the different colors will help there. I soldered and heat shrank the extension leads.



I ran the long bolts back through to reassemble the generator. And bought new brushes and connectors from Keith Moore.



Here is the generator with the brushes in and the field coil wires hanging out. The two copper posts are labeled "F" and "D", for Field and Dynamo. These posts have openings for the bullet connectors that will hold the wires that go to your voltage regulator.


As far as hooking up the brushes... The brush on the right here, goes to the "D" post. The brush on the left goes to the center post. The way to determine which field coil lead goes where, you'll need to attach one lead to the "F" post and the other to the center post.

I'm sure there's a way to get this right the first time, but I don't know it.



So in order to test that you have the field coil wires on the right posts, you'll need to take 2 wires with bullet connectors and plug them into the "D" and "F" terminals. Strip and and twist them together on the other end.

Take a battery charger (12 v is fine) And connect the Neg. lead to the genny body and positive lead to the "D" and "F" wires. The generator should motor in the direction of the arrow engraved in the body. Sorry. No pics or video of this working on my generator. If this works on yours, you've eliminated everything but the armature output.


If it goes the wrong way, switch the Field Coil leads.

Then re-install.

My armature was bad and still failed to put out voltage. Which is why some hack effed up my genny.

You can get the armature rewound for $140.

Hope this helps...

10-05-2010, 1:54 PM
This is really well laid out and the pics are great. You killed it on this one.

10-05-2010, 10:53 PM
This is really well laid out and the pics are great. You killed it on this one.

thanks man!

hopefully someone has a need for this. the alternator conversion is expensive as hell.

10-11-2010, 10:05 AM
Great job man, good info on that and great pics as well.