No Spark?!?!

[Mfa777]

Hi, I am new forum and just started trying to get my 1972 tiger running. I recently rewired it and rebuilt carb. I put a new battery in to test my wiring and the lights come on but I am not getting g a spark? I put new condensors and plug wires. I also simplified the wiring diagram to its basic functions.
On the Condensors. Do they need to be grounded if I am using original bracket?
Points are going to + side on coil (yellow black and black white wires) and the condensors are hooked up to the positives on coil as well. The negatives on coil are going to ign tab on the key switch. All wiring is positive ground.

Any suggestions? Using the attached wiring diagrahm.

 

[Rudie]

On the Condensors. Do they need to be grounded if I am using original bracket?

Yes. The original harness had a Red wire from the condensers mounting, almost all other all other electrical components also had a Red wire, all connected together and to the battery positive terminal.

I also simplified the wiring diagram to its basic functions.
Using the attached wiring diagrahm.

As BSA (Triumph's parent company in 1972) did not pay Lucas for anything more than "basic functions", what did you leave out in your "simplification"? Given your question about the condensers, the Red wires in the original harness are part of the basic functions so I hope you replaced them in your rewire?

 

[Mfa777]

Thank you Rudie! That makes sense. By simplified, I mean I don't have any signal lights and did not use the Lucas hand controls. However, I would like to use the hand control switches but have not wired them in. Thank you again!

 

[Mfa777]

Oddly I still have no spark? On the condensor there was a lil res isolator washer does that go between the plat and the condensor?

 

[Rudie]

On the condensor there was a lil res isolator washer does that go between the plat and the condensor?

There must be an electrical circuit through a condenser. On your bike, Black/White wire between one coil positive terminal and one condenser spade terminal, Black/Yellow wire between the other coil positive terminal and the other condenser spade terminal; both condensers attached to the base plate by their studs, harness Red wire attached somewhere on the base plate.

Do you have a parts book for your bike? If not, https://partsbooks.britishonly.com/partsbooks/20-10201C.pdf, condensor parts and mounting illustrated on book page 88, listed on page 89 (.pdf pages 90 and 91 respectively).

Possible an original harness did not have a Red wire connected specifically to the condensers base plate - Lucas did some really stupid things especially on the early OIF, like forgetting paint or rust do not conduct electricity ... If your bike does not have a Red wire to connect specifically to the condensers base plate, I advise adding one - ring terminal to fit a base plate screw on one end, bullet terminal to fit into a nearby existing snap connector on the other end.

Any "isolator washer" was supplied by an idiot.

still have no spark

Regrettably, I would be surprised if the disconnected condensers are responsible; normally, disconnected or dud condenser, just lots of sparks across the connected points as they open and close. Even with the condensers connected correctly, you might then have to start testing the ignition circuit from the ignition switch (that the lights work suggests the common part of the circuits between battery negative and the ignition switch works).

 

[Wavemaker]

Are you doing a back to original restoration? If not, have you looked into electronic ignition?