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TOPIC: low coil voltage

low coil voltage 11 years 1 month ago #54002

  • lemo32
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what would cause low voltage at the coil? lots of things my guess. i would want to do the coil mod, but i am so curious as to why i cannot get 12v to the coil.
wired george is a smart man way more than me but is this coil mod thing not a band aid that he so rightly
preaches against? only getting 8.5 volts to coil hellllp. The guy at dyna said to place one lead from ohm meter to the backing plate and the other to the white or black wire read resistance, should be none, well igot some. then he said i had troubles if i had resistance, he also said dyna s can control voltage to the coil? is this right?

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1979 kz 1000 06 katana 750

low coil voltage 11 years 1 month ago #54013

  • RonKZ650
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The dyna has no effect on voltage to the coils. 12v goes from your battery, through the fuse, through the ignition switch and various plugs/sockets to the coils. Each place is a possible voltage drop. Assuming the battery is 12v, it will take some voltage checks along the 12v through these items to find where voltage is being dropped low.
lemo32 wrote:

what would cause low voltage at the coil? lots of things my guess. i would want to do the coil mod, but i am so curious as to why i cannot get 12v to the coil.
wired george is a smart man way more than me but is this coil mod thing not a band aid that he so rightly
preaches against? only getting 8.5 volts to coil hellllp. The guy at dyna said to place one lead from ohm meter to the backing plate and the other to the white or black wire read resistance, should be none, well igot some. then he said i had troubles if i had resistance, he also said dyna s can control voltage to the coil? is this right?

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low coil voltage 11 years 1 month ago #54238

  • wiredgeorge
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Hey, don't do the coil mod... ITs your bike you can do whatever you want. Call Dyna tech support and ask them to help you wire your Dyna S so that it powers your coils for you... when they give you the wiring diagram, why not post it?

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low coil voltage 11 years 1 month ago #54251

  • Cardin
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Low voltage at the coils is a problem of every 30 year old connection, wire, and switch on your bike.


I'd go through the whole harness and check, clean and dialectric grease every relevant connection, and definitely clean and rebuild all the switch pods.

After that, I'd still put a relay under your seat and get 12+ volts to the coils. There are just too many terminals and switches and old wires to fight against.


I went the route of rewiring the whole bike and soldering every connection. Even though I had very clean and strong current to the ignition system, I still put a relay in partially because I like to have things organized well into systems, but mostly because clean power to the coils has made the hugest leap in performance of any work I've done on my bikes.

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low coil voltage 11 years 1 month ago #54256

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lemo32 wrote:

what would cause low voltage at the coil? lots of things my guess.


Things may be seen right

here
.

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low coil voltage 11 years 1 month ago #54296

  • wiredgeorge
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Duck... I would like to point out that on your wiring diagram... there is an error. The three wires coming off ANY Z1 or KZ900 stator are yellow and their specific connection to the regulator and rectifier are not required. Same AC on each. The Clymers, where the diagram came from is incorrect.

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low coil voltage 11 years 1 month ago #55212

  • loudhvx
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Sounds like you may have a ballast resistor in there somewhere. Look for a rectangular, ceramic thing about 3 inches long.

The Dyna tech I spoke to years ago had no clue what he was talking about, but acted like he did.

Ron has it right. The Dyna S only controls the negative side of the primary circuit of the coil. And yes, the Dyna S can overheat coils because the duty cycle is near 100% whereas a stock system is near 50%. (This means it has to dissipate twice the heat, but is given no time in which to do it.)

Newer coils seem to handle the abuse well, though.

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low coil voltage 11 years 1 month ago #55384

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i finally got 12 volts to the hot side of the coil wire,
now when i hook up the coils it gives me a low reading.
so dyna s or coils?

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1979 kz 1000 06 katana 750

low coil voltage 11 years 1 month ago #55870

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lemo32 wrote:

i finally got 12 volts to the hot side of the coil wire,
now when i hook up the coils it gives me a low reading.
so dyna s or coils?

Don't really understand what you're saying. What is giving a low reading, and what is a low reading?

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low coil voltage 11 years 1 month ago #55965

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whats happening is i get 12 volts to the hot wire that feeds the dyna and the coils. it stays 12 volts until i plug in the red wire on the dyna and wire up both coils then i get 8.5 volts across the coils. so either the dyna s is shorting to ground on the power side or the coils are shorting out.

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low coil voltage 11 years 1 month ago #56075

  • trippivot
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jumper wire 1 lead at a time across the connecter while monitoring the hot side voltage. you will isolate the bugger ground-short which ever

dyna causes so many problems.

newer kawasaki pieces will retro fit and have over 50,000 spark volts

Post edited by: trippivot, at: 2006/06/21 17:18

Post edited by: trippivot, at: 2006/06/21 17:19
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low coil voltage 11 years 1 month ago #56838

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lemo32 wrote:

whats happening is i get 12 volts to the hot wire that feeds the dyna and the coils. it stays 12 volts until i plug in the red wire on the dyna and wire up both coils then i get 8.5 volts across the coils. so either the dyna s is shorting to ground on the power side or the coils are shorting out.


This is to be expected. With the coils disconnected, there is no current so there can be no voltage drop. A voltage drop does not occur until there is a current.

The Dyna works such that both coil circuits are "on" most of the time. That is normal. Do not leave the ignition on for an extended time with the motor not running!

The voltage drop you get when the coils are hooked up indicate a ballast resistor may be hiding somewhere or you have bad wires/connections/ or switches that need to be cleaned or replaced. The shortcut method is to add the coil-relay mod.

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