Triumphrat

Tasmaniablue · 11-12-2012, 07:04 PM

Hello
I have posted regarding an intermittent ignition fault on my 06 Bonneville. I have fitted a new PVL coil and the bike seems to be ok now. I have been measuring the old coil primary resistance everyday for about a week. The reading was variable at first (I wonder why) and has now settled down to 0.1 ohm, sometimes 0. Spec is 0.5 ohm. My question is; does this reading indicate a faulty coil? My thoughts are that a low primary resistance reading would result if some of the windings were shorted together leading to insufficient flux to create a secondary voltage sufficient for a spark.
Here is another thought; Could a device be made along the lines of a buzzer that could be connected to the primary and a tester or spark plug connected to the secondary so that the coil would behave just as it would in a running engine. This set up could be run for a time to see if the coil breaks down. As you can see I just like to know what is going on.

H3CT1C · 11-14-2012, 01:14 PM

If it makes you feel any better my '05 Thruxton has been having similar problems.... secondary coil is in spec, but the primary coil is at 0.8 ohms. My first coil died after just over three years, coil number two just died, and coil number three is on the way, hope it corrects the problem... hope it also lasts longer than three and a half years...

Forchetto · 11-14-2012, 02:15 PM

Quote:

Originally Posted by Tasmaniablue

Could a device be made along the lines of a buzzer that could be connected to the primary and a tester or spark plug connected to the secondary so that the coil would behave just as it would in a running engine.

Yes, it's called something like "ignition coil driver". There are several circuit diagrams on the Net, like these:

And this super simple one using just a self-oscillating connection of a 12 volt relay with heavy contacts and a 0.47mf capacitor fed by a small 12 volt battery:

Tasmaniablue · 11-14-2012, 05:24 PM

Hello
Brilliant Forchetto. I wish I had the electronic assembly skills to make one of those. I presume they can be purchased commercially. Interesting that some people have multiple failures and others have no problems over many years of ownership. Coils in automotive applications seem to be super reliable. I wonder why failures in our motorcycles are not uncommon. The factors that I can identify that affect coil life are heat, vibration and quality of manufacture. Has anyone autopsied a dead coil to see precisely how it failed?

mikeinva · 11-15-2012, 04:50 PM

about 50% that people that think they have coil troubles end up being igniter troubles or other troubles.

Tasmaniablue · 11-15-2012, 10:56 PM

Hello
Hope I am in the right 50%! So far so good but any hint of further trouble and a Procom it will have to be.

Bron-Yr-Aur · 11-16-2012, 11:50 AM

Quote:

Originally Posted by mikeinva

about 50% that people that think they have coil troubles end up being igniter troubles or other troubles.

Yep, that's what happened to me. Now I have a backup coil, which isn't a bad thing. Fortunately they're not expensive. My HT side seemed to be out of spec, but it still worked.

mikeinva · 11-16-2012, 12:09 PM

Everyone that has one of these bikes and wants to keep it should buy cheap used spare parts.They will keep you from chaseing your tail when things go wrong.If I go on a long trip i carry a extra coil and igniter with me,they dont take up much room and it far better then being on the side the road dead.