Tips for Troubleshooting Flaky Connections

Hoping for some tips and tricks that have helped people troubleshoot flaky electrical connections. I’ve been having issues with my dyna coil kit. At low revs, the bike makes intermittent power, and I can hear the cylinders misfiring. Once it gets higher (about 3000 RPM), everything smooths out.

Given the symptom, I think it’s pretty clear there’s a poor connection somewhere, and once the bike’s vibration frequency gets high enough, it’s no longer losing connectivity for long enough to matter. But I’m.. kind of at a loss for how to figure out where the problem is? My multimeter shows proper connectivity everywhere, and all checkable resistances are in spec. What should I do, wiggle the wires around with the multimeter attached and see what happens?

 

Do you have the original Yamaha fuse box?

 

Nope, switched it out for the modern blade fuse version. The bike also runs fine on stock coils, so I think the fault must be somewhere between the two-pin connector going to each coil and the spark plug boots.

 

Two pin connector on my right coil was bad. I removed the terminals from the plastic block and replaced them. That fixed it.

 

I would be thinking carbs, but then in your last thread you mentioned it was better with OEM coils as far as missing at idle. So, sticking with electrical I would say you need to try another TCI or have someone install yours in their bike to test it. I could volunteer to test it but I am out of town for at least another couple of weeks, but maybe when i get back if you are interested. I also have a couple of spares so maybe we could just trade and I could send you a known good one.

 

I would be very surprised if it’s the TCI. It doesn’t just run better with the stock coils, it runs flawlessly. I just did another color tune and synch today, had no issues whatsoever. The only problem with the stock coils is that I don’t trust them in the rain. I’ve had the bike bog down in a storm before.

 

With the dynacoils at the low revs, get the bike in a dark place and look for errant sparking from the leads and coils to the frame and engine.
Shortest path and all.

 

I think this will probably be my next step. Those connectors are super cheap, so buying a new connector and swapping it in would be an easy step.

You know, it’s interesting you mention this. The last time I tried riding with the Dyna coils on, it was night time. I didn’t see any sparking from the plug wires, but the tank was in the way of anything on the coils themselves. Worth a shot to try this with the tank off.

I will say, I have run the bike with Dyna coils and the tank off before (just not in the dark), and I verified that it still stutters. So, at least I’m confident that I don’t have arcing to the tank itself. Len’s mounting bracket kit does a fantastic job of creating clearance from the tank; there’s more clearance even than the stock coils have.

 

Did you check voltage at the red two pin connectors from tci to coil. Check for resistance too from tci on the red white stripe and grey wire. Or orange cannot remember lol.