where to start looking

Ok here is the problem
Riding on the weekend bike started fist kick and away I go bike seemed a bit flat throuhout the rev range and down on power but still ridable
it misfired a couple of times and I headed back home parked bike in drive way . check fuel deliver all good, checked spark plug leads all good went to restart bike and I have no spark at the plugs.
1973 850 all standard with the exception of a Tri spark
have ignition lights when turn the key on
no led light on trispark when kicking over
no spark at plugs
any quick guess where problem might be before i remove tank etc
I am hopless on electrikery stuff
cheers in advance

Kill switch and key switch without perfection here all is lost.

thanks just checked both and all good with kill switch and ignition ???

Well if you have no red light you need to meter the power into the Trispark to see that it is receiving power. Have you a good ground to the head? Is there a copper path way unbroken from the head to the battery?

Any chance the voltage of your battery is down below the level the tri spark needs?

rx7171 said:

Any chance the voltage of your battery is down below the level the tri spark needs?

Click to expand...

From their site 7 1/2 volts mentioned as minimum.

My ignition switch plays silly buggers occasionally.

Kanaka, I can't see how one can operate a Commando for long without acquiring some level of electrical troubleshooting skills. If this has been a closed book to you up to now, it's a great time to expand your horizons. It's not rocket surgery. This is just general advice. One with a Commando needs a multimeter and a 6 foot long pair of jumpers with alligator clips on the ends. A digital multimeter is about the size of a deck of cards and will measure voltage and resistance. Perfect for locating shorts and gaps. Jumpers make it easy to power up components directly from the battery and tracing backward why something ain't working.
Specific to ignition wiring, I am a big fan of powering it up with a relay. It doesn't replace the switches and buttons in the stock circuit. It uses them to power up a a sealed switch which runs a separate fused line from the battery to the ignition. The stock circuit's buttons and switches, corroding connectors, and fraying wires then only have to carry mere trickle of current, which they can be counted on to do admirably. In an intermittent way.
Do TriSpark's have any issues with the wiring under the cover like Boyers do?

If he has a TriSpark classic, it's like a hockey puck, it either works or it doesn't. Although I don't have one, and if it worked before and suddenly stopped, the first likely suspects are the wires going to the coil(s) and the ground(s) going to the engine since the classic uses the frame as a return. Every wire carrying power to the coil(s) and to the puck must be checked too. Of course, if everything checks out, then make sure the magnet is properly positionned, then and only then the problem may be with the unit itself.

Jean

You need to check the wiring inside the points cover where they connect to the ignition module. I had a failure this year when one of the wires broke at the bullet connector, but the break was hidden by my heatshrink tubing. A voltmeter across the power and ground wires directly at the module will tell you a lot.

well i went to a dark place today and went to the tool box with the test light and multi meter worked my way from tri spark through to coils and found a broken teminal soldered and fitted new terminal and all good thanks again for the advice and courage to tackle myself cheers