Points & Condenser the same for 12 V ? Doing an upgrade, no spark

[tonyduc]

I installed a new Electrix 12V conversion kit for my 67 MK3 magneto bike. Testing the unit for spark at the plug, nothing. I am using a fresh 12 V battery, and I did a quick wiring setup directly from the battery to a Dyna 12V 3 ohm coil, (+) pole from battery +, other pole wired to ignition points.Otherwise I followed their diagram: 2 yellow wires to RR, from RR red to + battery, green to (-) battery which is subsequently grounded. The spark plug and plug wire I took from my running Guzzi so I know that they are working fine. I know the plug is not correct but I am just testing for spark right now. Kinda puzzling, I am thinking maybe the condenser is bad, or since the points and condenser are from the 6 v setup do I need something suited for 12 V ?
Thanks
Tony

[ranton_rambler]

As far as I know, it’s the same for 6V or 12V. My 12V 175 with Electrex R-R has it’s original 50 year old condenser fitted as the new replacement died very quickly.
Are you sure you’ve got the various insulation bits at the points in the right places?
Ian

[veloduke]

Hi Tony

The points and condensor will work with 6V or 12V. I think maybe the best thing to do is to completely disconnect the Electrex setup so that you are left with just battery/coil/points/condensor. Then you can check where you have volts starting at battery, coil, points. The minus (-) side of the coil should change depending whether the points are open or closed.
If there is no voltage at the -ve of the coil then your points are likely permanently grounded.
If you only ever see 12V at the -ve coil terminal then you have a grounding issue at the points assy, or the condensor has gone short circuit.
You can disconnect the condensor for testing - you will get a spark, but the bike won't run correctly.

Also (you probably know this) the blue wire loop in the Electrex RR needs cutting for 12V.

Hope this helps somewhat.

[tonyduc]

Thanks to both. Got spark ! Turns out that the points were grounded. The plastic cylinder that attaches the points to the back plate had slid up when I first took the points out. I did not slide it all the way back in so the points were touching the back plate causing a permanent closed circuit. It needs to extend a little beyond the back side of the points - I also put and o-ring around it to make sure there is separate of the two plates. Hope I did not cause any damage to the coil, it was getting warm before I found the short.
No on to the fuel system !
Tony