Ignition Coil Relay Mod

[ben2go]

This site,nor I,will be held responsible for damages to your bike if you attempt this modification.If you have doubts,seek help from a professional.




Symptoms-Sporadic cutting back and hesitation from idle through 3500rpm.Engine temperature has little effect on condition.

Attempts to resolve the problem.
Multiple carb cleanings
Multiple electrical connection cleanings
Clean tank tank and fill with fresh fuel
Multiple valve clearance checks
Multiple carb balance/sync
Complete electrical system tear down and diagnose

Problem- 11.8 volts at the ignition coil terminals.Should be an absolute minimum of 12.0 volts.

The cure- Ignition coil relay mod.Power the coils directly from the battery and grounding the coils directly to the battery.

After reading about the ignition coil relay mod over on http://www.thegsresources.com/_forum/index.php forum,I visited http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html Then I did the ignition relay mod.I haven't yet had a chance to ride and see if the problem resolves itself.I am positive that this mod can only help.I will hopefully be heading out in a little while to ride and see how the mod performs.I'm a wuss and have to wait for the afternoon warm up.

To do this mod you need the following.

Tools
wire strippers
soldering iron,gun,or pencil torch
wire cutters
needle nose pliers
metric socket set
JIS screw driver or philips head
long flat head/blade screw driver
scissors
BBQ or cigerette lighter
Dielectric grease
Small piece of sand paper- 40 to 200 grit

Supplies with cost break down.
$3.00 1/4 male spade terminals
$3.00 1.4 female terminals
$3.00 10 gauge uninsulated but connectors
$3.00 heat shrink kit from Harbor Freight
$4.00 14 gauge red primary wire 12'roll
$4.00 14 gauge black primary wire 12' roll
$7.00 solder
$1.00 electrical tape roll
$3.00 black wire ties
$5.00 30 amp horn/light relay
$7.00 30 amp fuse holder
$4.00 20 amp fuse-I could only get these in boxes of five.


$47.00 Total

If you can find it,use 16 gauge orange wire for the relay to ignition on wire.This will make sense later.I couldn't find orange wire locally.

Most of us have some of these supplies on hand.I did and I think my final cost was under $20.One thing I can not stress enough,DO NOT USE ELECTRICAL SUPPLIES FROM HARBOR FREIGHT.The shrink tubing is good.Their wire is copper coated aluminum and their connectors are aluminum.The connectors I used are marine grade.They are expensive and over kill for this project.You can also use connectors with shrink wrap insulation and/or connector covers.I chose to use shrink wrap because I had uninsulated connectors.I despise the connectors with plastic on the bases.I usually pull the plastic off and use shrink wrap.

[ben2go]

On with it.The ignition coils will be powered directly from the battery by the relay.The relay will be powered by the old ignition coil power wire.There are two.Only one will be used.The coils will also be grounded dirrectly to the battery.This isn't complicated.Just take it one wire run at a time.All connections are coated with dielectric grease.

Here is the wiring diagram that I followed.This is from Bass Cliff's website linked above.


Remove the seat,battery,all the tail plastics,and fuel tank.Don't forget to turn off the tank petcock.


First thing I did was to locate,unplug,and tape off the left coil wire that wasn't going to be used.






I wire tied this to the frame.The pic I had of it has been lost.It may be visable in other pics.


Next I mounted the relay.Try to mount it as close to the battery as possible but leave enough room for the inline fuse.This is how I did it.

Locate and remove the right side hemet hook/lock and bolt down relay.No,it isn't touching the regulator rectifier.that is getting replaced later.

[seamax]

Thanks Ben. Although I don't have this problem on my GS500, I do have it on my '79 GS425 and my carbs have been thoroughly cleaned and rejetted. I have the exact symptoms as in the article you linked...

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html

It is simple enough that I will give this a try.

[ben2go]

Some of my pics were lost, so I will walk through this using my existing pics.

First thing I did was run power from the starter relay to the inline fuse and plug it into the relay.

I made connections to make the inline fuse removable.I have had these go bad and wanted to make it easy to replace.
I crimped and soldered my connections.Then I double shrink wrapped each terminal.All of my connections will be like this or better.






I ran a short wire into the starter relay cover using 12 gauge primary wire.


Pull off those two white plugs.The lower terminal is the one that is powered all the time.





Run the wire up through the relay cover,install a ring connector like so,and bolt it on.






Install a spade connector on the end of the wire that was just connected to the starter relay.Then connect the inline fuse holder to the starter relay wire and terminal 30 on the relay.


Add some shrink wrap to help secure and protect the connection.




Install fuse and admire.


Here you can also see the relay ground.It is a simple loop of wire with a ring terminal on one end and a female terminal on the other end.It connects to terminal 85 on the relay.

[ben2go]

Powering the coils from the relay.I installed a female connector on the end of my red wire roll and connected it to terminal 87 on the relay.They I unrolled the wire and ran it along the main wiring harness on the right side of the frame.I cut it off when I made it up between the coils and installed a but connector.Then I made two short wires with female connectors to run to each coil terminal.I removed the wiring for solder and shrink wrap.





here the wiring is connected to the coil + positive terminal.You can also see how I taped and wire tied the old connector.

[ben2go]

Some notes here about the trigger wire for the relay.If you can find 16 gauge orange wire,use it.The original coil wire is orange with a white or green stripe.This makes it easier to know what wire is what,should a problem arise.You could also use thinner 16 gauge red primary wire or loner lengths of shrink wrap to help distingish between the two.This wire is also protected by the main wiring harness fuse so no other fuse will be needed.

The connection is super easy almost as easy as the relay ground.I installed a female terminal on the end of my red roll of primary wire and ran it along the main wiring harness.I cut it off at the right coil + positive wire.I installed a spade terminal,pulled out the old coil + positive wire,connected them, and shrink wrapped The connection.I pushed the original coil wire cover back in place.






Now the wiring can be tucked away and the coil to battery ground can be ran.

[ben2go]

The coils are grounded to the frame and over time the connection is lost due to corrosion and rust.This mod helps to offset that.

First thing is to make up two 8 inch wires with ring connectors like so.


Then add a but connector to the two short wires and connect the black roll of 12 gauge primary wire.Here is a pic of the but connection from earlier as a reminder.



Remove the inside coil mount bolts and connect the wires with the ring terminals like so.Be aware that the aluminum coil stand offs will drop out when the bolt is removed.Clean the metal coil end with sand paper and bolt the ring terminals on the coils.


Unroll the wire and run it along the main harness until it makes it to the battery negative terminal.Install a ring connector.



Now comes the fun part,securing the wiring.I used plastic zip ties.It looks pretty good considering it was a rush job.There is a glare or something at the top of the pic that makes it look like there is more wires thatn there actual is.



After this mod,my voltage went from 11.8 to 12.4 with a battery that has set for six months without use.I expect the voltage to be higher after I run the bike and build the battery back up. 

Do not forget to turn that damn tank petcock back on.

Please note that I had to remove the wiring and take it into my building to solder the wiring.I left the camera outside with the bike.

[ben2go]

Thanks Ben. Although I don't have this problem on my GS500, I do have it on my '79 GS425 and my carbs have been thoroughly cleaned and rejetted. I have the exact symptoms as in the article you linked...

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html

It is simple enough that I will give this a try.

You're welcome.I think it's a good idea to do this mod on older bikes that have corrosion issues.

[ben2go]

Ok,so this location won't work.The seat comes down to far.I will post the new location when I get everything assembled.I'm trying to make it easy as possible without using special tools, like a drill.

[Funderb]

one of the screws on either side of the rectifier might have lots of room under the fairing? its within a couple inches of where it is already.

[ben2go]

Here's the revised relay mounting.I flipped it to face rearward.Problem solved


Clears the seat.


Clears the plastic.




I got a chance to take a 20 mile ride.Idle is way more stable.Before I would occasionally get a miss fire and drop a few rpm.I have no lag or hesitation between 1200rpm and 3500rpm.It actually pulls hard from idle all the way to red line.If I slow down to 2000rpm in 3rd,4th,or 5th,I have no problems with lag and skipping when rolling on the power.No more unburnt fuel smell after coming off the highway and stopping at signal.Overall,it's worth it.Engine warms up way faster and a carb sync/balance is easier to set.I'm happy.I hope it doesn't rain this weekend.

[Funderb]

hell yeah!
I might be doing this soon/now.
Except its my girlfriend's birthday, and I'm supposed to be making dinner.
So now might not reflect well for the night.

[ben2go]

hell yeah!
I might be doing this soon/now.
Except its my girlfriend's birthday, and I'm supposed to be making dinner.
So now might not reflect well for the night.

What!?You're putting a girl before bike time?I hope you don't miss out on her desert. 

All kidding aside,it's really easy.It seems daunting at first.Once the first wire is laid in,the rest are nothing.Just remember to leave a little extra wire,in case of a mess up.

[Funderb]

ben, i tested my bike at two intervals, one with just the key on, not running, and the low voltage terminal was at, say 11.4 volts. battery voltage is 13.1

with the bike running, at idle, voltage popped up to 12.3, but battery voltage was 13.6, still more than a volt low.

do you think its necessary to do this mod, or is the running voltage adequate? I wasn't sure in what state you tested, but the voltage drop seems pretty bad.

[ben2go]

ben, i tested my bike at two intervals, one with just the key on, not running, and the low voltage terminal was at, say 11.4 volts. battery voltage is 13.1

with the bike running, at idle, voltage popped up to 12.3, but battery voltage was 13.6, still more than a volt low.

do you think its necessary to do this mod, or is the running voltage adequate? I wasn't sure in what state you tested, but the voltage drop seems pretty bad.

It would help bring the voltage up at the coils.Test the voltage at the coils and battery at 5000 rpm.If the voltage drops below 12.0v then yes,I would put it high on the to do list.I'm not an expert but everything I have read says a minimum of 12v at the coils.I do know that over time wiring becomes tarnished and corroded under the insulation close to the ends.That will affect voltage some.I have a chopped up harness that I am redoing to get the connectors out of the headlight.The wiring is tarnished and corroded pretty bad just passed the terminals into the insulating cover.

Here's the harness.It has 1865 miles on it.Someone felt the need to chop it up and then wire nut it back together and wrap it in vinyl and  shipping tape.

[jpaytoncfd]

Awsome fix! I actually did the same thing in my truck and girlfriends jeep. Stock wireing in everything is so cheaply made. I did Ignition coils, Headlights, and trailer plug. I make one over sized lead from the battery to each of the effected areas. Almost doubled my light output on high beam.

I will have to check around my new gs500f. I would think a motorcycle would have a little more heavy duty wiring but I have already notice a few wires that are exposed and not attached very well.

[ben2go]

Awsome fix! I actually did the same thing in my truck and girlfriends jeep. Stock wireing in everything is so cheaply made. I did Ignition coils, Headlights, and trailer plug. I make one over sized lead from the battery to each of the effected areas. Almost doubled my light output on high beam.

I will have to check around my new gs500f. I would think a motorcycle would have a little more heavy duty wiring but I have already notice a few wires that are exposed and not attached very well.

This wouldn't be needed on a F until it gets some age on it or is left outside 24/7/365.

[jpaytoncfd]

The ignition coil looks fine but the turn signal wiring is horrible. Tails don't look too good either. I just replaced the gauge lights with leds. those all looked fine.

I got this bike from a guy that bought it from auction. It had a bent fork. he replaced it for his son who lost his license. anyway, it has been sitting in an auction lot for 3 years.

[adidasguy]

I think Phenix suffers from a weak ground to the coils. Since the frame was completely repainted before I acquired it, he must have a weak ground to the frame.

Engine is OK due to the heavy ground right to the engine.

Coil gruond I think is weak resulting in weak spark as he gets fussy when really cold (40*) and I notice that when letting up on the starter, he then takes off. That's because the voltage went back up and the inertia in the engine spun it a couple more times and hence higher voltage and he's happier and runs.

I have had him stop when cold, just started and idling slow. Slight drop in voltage and he is not happy.
I'll run a new ground first - I think I can do that without removing the tank. I'll furst see what the resistance is between the coil frame and the battery negative terminal.