Re-powering Ignition Coils ?

I ran across an article by Wired George on re-powering ignition coils running a separate circuit with a 5-pin relay and harness. I measured the voltage at the coils as he suggested and both tested the same as 8.98 Volts with the key on/engine off. So obviously less than 12 Volts.

My Bike even though it's tired, is becoming harder and harder to start. All mechanicals and electricals are within spec. and have ridden this bike for several hundred miles, but these are the stock coils and wires. I did change out the spark plug caps to new.

So as the article states, do you think it's worth an attempt to wire in this relay to see if it helps with the starting ?

Hi kzdcw,
That's a lot of voltage drop. Sounds like a good candidate for the relay mod.

Good Ridin'
slmjim & Z1BEBE

kzdcw wrote: I ran across an article by Wired George on re-powering ignition coils running a separate circuit with a 5-pin relay and harness. I measured the voltage at the coils as he suggested and both tested the same as 8.98 Volts with the key on/engine off. So obviously less than 12 Volts.

My Bike even though it's tired, is becoming harder and harder to start. All mechanicals and electricals are within spec. and have ridden this bike for several hundred miles, but these are the stock coils and wires. I did change out the spark plug caps to new.

So as the article states, do you think it's worth an attempt to wire in this relay to see if it helps with the starting ?

Does this engine use mechanical points or electronic ignition?

Mechanical Points .

Some people recommend doing this mod, others say that it is not needed instead recommending going through your wiring and cleaning every connection and using dielectric grease. I've had good success using both ways.

I installed a the relay on my 76 KZ400 and it worked great and really seemed to make a difference. And I really like the click of the relay switching on, in fact I've gotten so used to it that sound that when I did not use a relay for my 78 KZ400 yet because I had gone through every inch of the wiring harness and cleaned up every connector that I thought something was wrong when I didn't hear the click I was used to when I switched it on.

It is a fairly simple modification and if you are having issues it is a quick and reliable fix.

+1 on cleaning upp the connectors before considering the mod. In doing so, you may not only avoid needing the mod, but may also fix other problems that you are not yet aware of and may even be able to prevent a problem by spotting trouble in the making.
I recommend using a dedicated electrical cleaner like Deoxit D5. It will amaze you. Some small brass brushes and cotton swabs will be good for the really stubborn gunk. I do not recommend dielectric grease as it can interfere with electical flow.
ymmv

The problem is that is it masks the real problem of the voltage loss. This can lead to an over-charging problem on some bikes which will boil out the battery. It's always a good idea to address the real problem to prevent more problems in the future.

How about just installing New Coils and Wires ?

When I originally put this bike together, I went thru "All" connections and cleaned then pretty well.

Hi kzdcw,
The contacts in the ignition switch are usually the main culprit in voltage drop at the coils. Unless you want to disassemble the ignition switch there's no good, sure fire way to clean them. As others has stated, it's a good idea to freshen all the connections too.

GoodRidin'
slmjim & Z1BEBE

Did you disassemble the ignition switch and kill switch. That's what I usually end up doing, but also the fuse holder area is very problematic.

The ignition switch is New. I did take apart the kill switch and clean the inside connections with electrical cleaner. Also the fuse holder, I cleaned all the copper fuse holders with a light emory cloth.

Hi kzdcw,
Even though the switch is new, a great deal of current must pass through it between the battery and the rest of the bike.

Sounds like you've done your due diligence. Try tracing from the coils back toward the battery with a voltmeter to see where the drop is happening.

Forgot to ask the 1st time; key on/engine off, what is the voltage across the battery?

Good Ridin'
slmjim & Z1BEBE

Good Ridin'
slmjim & Z1BEBE