Triumphrat

Geoffrey M

I have a 1973 750 Bonneville. She started fine ran for about a mile and died in 3rd gear. I slowed down geared down to 2nd and popped the clutch and she restarted then died again. I tried to kick her over (with the temp and humidity about 100 and my age 55 it was a good work out!) but to no avail. I was getting no ignition light, signals, horn all dead. I run with the headlight on but noticed the horn not working earlier in the day when I started it up. She had not been run for about 3 weeks prior. I was about a 1/2 mile from home at this point. Got another work out pushing her home. Once home I recharged the battery overnight. Plugs were slightly fouled so I replaced them as well but still no spark when I place one to cylinder head and kick over. I checked all wiring and fuse - no shorts that I can see and fuse is okay. Is my recifier shot? I thought I could run the bike even without a batter but no amout of kicking would start her. Any ideas?

gabsdad8

Although I don't think that I can help much, I'm subscribing to your post to bring it back to the top. People on here have been a great help to me, I don't know why no one has answered you. Maybe more information is needed... What type of ignition system? How about carbs? Are you positive that your battery took a charge? Were you running without a battery when it died?

Webby

Hi Geoffrey,

First off welcome to the forum, and now on to the important stuff

OK, so you've checked the fuse, and checked the wiring so I'll assume that it's not the fuse, or the connection to the battery. All the symptoms point to no current anywhere in the circuit so I would suggest you test the following (get yourself a multimeter & wiring diagram before you start)

Fuse Holder
Ignition Switch
Ground Connection
Wiring connectors (in the headlamp or under the tank)

For info my 72 (not sure if it's the same) has a blue/brown wire from the battery negative to the switch and a white wire as the return.

Good Luck

Webby

pookybear

Geoffrey M,

Well nothing like a disaster to bring you to the pages of Triumph
Rat. Sorry it could not be in better riding days for you, but for
what it is worth, Welcome.

As for your problem, why you are here in the first place. All I have
to ask is this. Even after you have charged your battery overnight
did you get the ignition light start working? How about the other
electrical items, horn, signals, head light?

If no you are looking right around the battery, you stated you have
checked the postitive side with the fuse. Check the ground as well.
If all circuts are affected, then the problem is with the common
point of all the wiring.

I hope this helps you out of your problem,

Pookybear

thirdbike

Welcome Geoffrey and a nice model year. I didn't spot your post till now.

To give you a hand, a little more info is needed. You know what your bike looks like and has on it but my computer ain't that slick yet to dig it up for us. When they make one of those computers that pops the hood and spits it all out for me - come to think of it, you won't be asking, will you? Not meaning to insult your intelligence here so don't take it that I'm asking dumb questions but we need to get on the same page before anybody can help out. Once the simple stuff is known the harder stuff follows.

I'm with Webby, the problem does sound electrical. Have you made any recent changes to the bike?
What kind ignition do you have - Points or electronic - Boyer etc? If points, I would check them first to check if they haven't stuck or something. What kind of rectifier are you using? If electronic ignition, what kind of plugs wires and caps? Did the battery go dead or low? What did your battery read then and now. You won't get a spark if you have an electronic ignition with the battery dropping below 11.2 volts. Your battery should hold a charge overnight of minimum of 12.4 volts. If not, check the electrolyte and if it is OK then time for a new one.
If your battery is fully charged and your points are good and all the wires are connected, you should be getting a spark even if there is a problem with the charging system which still has to be diagnosed.
Give us as much info as you are willing to share. Somebody will definitely get back to you.

epynt1050

If the battery is holding charge after being recharged (better than 12v) and the electrical circuit is still dead, then it is a matter of tracing through the wiring until you locate the fault.
You will need the factory manual (for the circuit diagram) and a multimeter. First check the earth connection from the battery for continuity. Then check the feed to the main on/off switch (the one with the key). Then check the feeds out of the switch with the switch on. I expect by this point you will have found the problem. If not, then start checking the circuits to the horn, lights etc. Eventually you will locate the problem.

Geoffrey M

Thanks for the suggestions. It is the original wiring harness and components on this one. No modifications. Problem could be in the fuse holder. One end contact was missing and therefore not making contact with the fuse (which had not blown). Took some time to find this as it was only by chance taking out the fuse and looking into the holder. Stores are closed today (Canada Day) so once I get this fixed I am hoping it will start. I will check the whole wiring system for any other shorts with a multimeter. Thanks for the help.

pookybear

Geoffrey,

Ah yes connectors, one of the biggest problems with an old wire
harness. Glad you found something to fix. And this problem
would be an open circut concern. It would also cover the
symptom of when you popped the clutch in second gear and it
ran for a second. It made a connection for a moment and then
opened back up again.

Let us know when you get the fuse holder in and if it fixed the
problem or not.

Have a good Canada Day,

Pookybear