NGWClub®, Inc.

My 78 will occasionally cut out when first started and running after a lot of short rides and starts. I read recently a dynatech ign. may be sensitive to low voltage. Today warmed up at idle with the fan running and the digital meter in the windjammer it was reading just over 11 volts. At 3K rpm it will rise to nearly 14V during a ride, then slowly drop back which may be normal . Still has the dyno plug which looks good, has been cleaned, polished and silicone greased. Recent agm battery, maintained off season.
Anyway after optimizing the connections, should I add a relay to secure max volts to the coils? It has no ballast resistor, two gl1500 3 ohm coils, new wires and caps and a recent Dynatech ign .
It has mostly new everything, from the gas cap to the intake o rings, and the plugs to the ign switch. It still does the occasional cut out, like the switch was bumped off.
I've thought of running a temporary hot wire from the battery to the ign. just as a test.

Mine would miss with a blinker on (minor voltage drop) until I put the ignition on a relay. Very solid now. Well worth the effort.

As long as it’s fused, you would be safe. Lots have added the relay for the same reason.

I believe Dana’s suggestion was to wire direct to the battery back when they had “black box” (Dyna 111 models) issues. If it fixed it: great. If not: send it in.

You can certainly run a temporary as a quick means of troubleshooting. Also run a temporary Ground. Or if you have a decent multi-meter you can read the voltage drop from the neg batt terminal to the engine block and see if it is enough to fuss over.

I found a mounting base for the bosch relay at Advance auto, they didn't know they had them until they looked, new item, I bought all four since I have a car to wire too.

FWIW, I power mine from the accessory port and switch it with the kill switch.

1) Try jiggling the kill switch while it is running to make sure that isn't causing the problem. It should need to be turned quite a bit before it shuts the ignition off so if it is over-sensitive clean the kill switch contacts. Try spraying contact cleaner into the switch housing (key OFF) through the holes in the bottom of the housing and working the switch a bunch of times but you may need to open the housing to get at it properly.

2) If your Dyna is wired per the instructions, try changing where it gets power to the wire that powers the coils before you add a relay. I don't know who thought of powering the electronic ignition from the turn signal circuit but they should be given a stern talking to
It makes far more sense to power it from the ignition circuit...

I have my dyna ignition running off of the turn signal wire, which only gets 11 or 11.5 volts and get a miss after i rev the engine and it returns to idle. If I use a relay to run my dyna, what amp rated fuse should I be installing in the line?

Probably the same value as the turn signal is on.

For the record, mine is connected to the wire that powers the coils and I don't have that problem...

1983lux wrote: ↑Thu Sep 03, 2020 6:20 pm I have my dyna ignition running off of the turn signal wire, which only gets 11 or 11.5 volts and get a miss after i rev the engine and it returns to idle. If I use a relay to run my dyna, what amp rated fuse should I be installing in the line?

5 Amps should be plenty. It doesn't supply ignition power, it just runs the Dyna electronics.

Mine (Dyna) is also running on the accessory plug at this time.

Don R wrote: ↑Sat Sep 05, 2020 11:44 am Mine (Dyna) is also running on the accessory plug at this time.

My Hunley is also, but I've probably not ridden it over 100 miles this summer.

I used the accessory terminal to operate a relay with clean power from the battery. It runs the dyna and the fuel pump.

This was great advice. Hooked my Dyna and fuel pump to a relay. Was getting 11.0-11.5 volts before off some white wire with green stripe with a dual socket connector at the end.. With the full 12 volts off the relay it runs, starts and sounds really different. Huge change for the better. I've had the bike randomly shut off a few times while decelerating and I wonder if this was why. Never would've thought of this!

That's good to hear it helps. I still haven't done it, I'm building a car and trying to put together a pair of cb750 K0 projects to re-sell for car money. Otherwise known as, lots of lame excuses.