IGNITION COIL RELAY MODIFICATION

Please share your secrets! What mods have you made to your TRX?

Moderators: trixynut, Mincehead, dicky, phuk72, Jak, Kevtrx849

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Thu Apr 09, 2015 1:09 pm

Image

Time to rebuild my wiring loom and re terminate the mods I have done with better connectors.
I'm also changing the power feed to the coils to work directly from the battery via a relay.
Simple test is to meter the voltage at your battery and then meter the voltage at your coils.
There will be odds on you have a voltage drop and under 12v so your not getting the full potential out of your coils.

There are 4 wires
What I'm doing here is using the original coil feed from cylinder1 as the power to trigger the relay when the ignition is turned on. (green wire and black earth wire attached to relay complete this circuit.)
Cylinder 2 original coil feed I will use as the trigger on a 2nd relay for my O2 sensor set up.
( you don't need it just tape it up or you can use it as I have for an accessory feed)

So when triggered this opens the circuit to draw power directly from the battery through the relay to the coils (shorter heavier red cable and the longer heavier red cable coiled up with the Y split to feed both coils attached to relay)
The result being a stronger spark 8) simple performance modification and at no detriment to the std coils.
The relay I have chosen to use has added protection with a built in fuse from the battery feed and the original cylinder 1 ignition feed used to trigger the relay already runs through the original TRX ignition fuse in the fusebox so there is protection for both feeds to the relay. :wink: .

Heavier 15amp cable is used on the battery/coil feeds and all connectors are crimped,soldered and then heat shrink for insulation.
I will be mounting mine under the front section of the R/H side cover beside the battery tray.

I'll be making up another 3 so if anyone wants one ($30 shipped in Oz) send me a PM.
I've used ring terminals not spade terminals on my coil feeds due to the Dynatek coils and the others I make will have insulated spades to suit the std TRX coils.
The green wire will have a blade terminal to connect to the original wiring harness so everything plugs straight inplace on the std TRX loom and coils.
Ring terminals are used for the battery feed and earth.
I will be taking my battery feed straight from the battery side of the starter relay.

You can easily remove the fuse from the relay as an added anti theft device too.
So if they know how to Hotwire the std ignition switch, this will slow them down why they trace why they still have no spark. :)
laughter is the best medicine

Rich
Site Sponsor
Posts: 217
Joined: Mon Dec 23, 2013 8:20 pm
Location: Derbyshire UK

Re: IGNITION COIL RELAY MODIFICATION

Post by Rich » Thu Apr 09, 2015 4:24 pm

best to check the earths as well.

User avatar
dandywarhol
Site Sponsor
Posts: 1639
Joined: Fri Nov 24, 2006 12:56 pm
Location: Edinburgh, Scotland

Re: IGNITION COIL RELAY MODIFICATION

Post by dandywarhol » Thu Apr 09, 2015 5:52 pm

What's the difference in volt drop between the original and modified systems Cobba?
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

User avatar
M.V.
Site Sponsor
Posts: 1509
Joined: Sat Jul 04, 2009 3:23 am
Location: Melbourne, Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by M.V. » Fri Apr 10, 2015 4:32 am

dandywarhol wrote:What's the difference in volt drop between the original and modified systems Cobba?
Yes, interested to know. Interested in a harness too if the drop is significant.

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Fri Apr 10, 2015 11:30 am

What I'm acheiving by this is bypassing a few extra connectors, switches and cable length & thinner gauge cabling.
The power to the coils runs from the ignition key through the neutral & side stand switches, the LHS handlebar clutch switch and ECU , back up to the handlebars on the RHS and through the kill switch and then to the coils. The headlight power is drawn along this feed too .
So I have effectively bypassed any extra load, all these switches and connectors and all these 0.1-0.2v losses start to add up.

Any voltage loss or extra load now is not an issue as the original coil feed is only used to trigger the relay which needs 2/10th of bugger all.
Voltage to the coils now runs down a 4mm /15amp cable about 500mm long straight from the battery with only the relay inline.


Cleaning all the connectors and switches will help but you can't stop wear n tear after 20 yrs.
I had cleaned all these point during the rebuild and I was suprised how much grime had built up even on the std connectors still in use on the harness.

I never bothered to meter the coils before the mod as I knew I would gain from previous experience.
As someone mentioned before, a good earth is a must too.

Australian model TRX's have the headlight hard wired and on as soon as you turn the key and this is drawing power along the same chain to that feeds the coils so a simple test is take a voltage reading from the battery, then one from the coil feed black/red lead.
Take a reading under load too when you hit the starter and motor idling.
Don't forget to meter the battery while idling too.
laughter is the best medicine

Rich
Site Sponsor
Posts: 217
Joined: Mon Dec 23, 2013 8:20 pm
Location: Derbyshire UK

Re: IGNITION COIL RELAY MODIFICATION

Post by Rich » Fri Apr 10, 2015 9:05 pm

common mod for old Kwak z900/1000, maybe worth putting a doide on the relay coil as well.

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Sat Apr 11, 2015 4:55 am

Finished the harness rebuild last nite and had the chance to fire it up this morning.
Ignition on, the battery and the coils meter 13.6v and with the motor running they both come at 14.3v .
Motor response is beautiful as I was expecting, sounds clean and crisp and revs with no hesitation right from idle.
laughter is the best medicine

User avatar
Rod.s
Site Sponsor
Posts: 1404
Joined: Sun Apr 25, 2010 11:01 am
Location: Brisbane, Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by Rod.s » Sat Apr 11, 2015 5:22 am

cobbadiggabuddyblooo wrote:Finished the harness rebuild last nite and had the chance to fire it up this morning.
Ignition on, the battery and the coils meter 13.6v and with the motor running they both come at 14.3v .
Motor response is beautiful as I was expecting, sounds clean and crisp and revs with no hesitation right from idle.
Those coils are good for that voltage and where you have them positioned will keep any extra heat generated at bay :D well done.
If it's not made in China, it's a fake!

User avatar
dandywarhol
Site Sponsor
Posts: 1639
Joined: Fri Nov 24, 2006 12:56 pm
Location: Edinburgh, Scotland

Re: IGNITION COIL RELAY MODIFICATION

Post by dandywarhol » Sat Apr 11, 2015 9:06 am

You running a stock battery cobba?I wouldn't expect to see any more than 12.6 from a fully charged battery after the surface discharge has been removed by the coils :?:
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Sat Apr 11, 2015 9:26 am

Shorai Lithium ion


LFX18L1-BS12
SHORAI LFX Lithium-Iron Powersports battery, 18Ah PbEq 12V eq, “L” polarity, Case Type 1
Sku: 4897034420135
Part Number: LFX18L1-BS12

Specifications

Weight (grams): 1048
Cranking CCA (A): 270
Weight (lbs.): 2.31
laughter is the best medicine

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Mon Apr 13, 2015 3:36 am

Took the bike for a bit of a ride to book in on a dyno run and have definately found gains with this mod.
8) 8) 8) 8)
Finding more low down torque and overall running with pick up through the rev range in top gear roll ons with no hesitation and just asks for more. ( as the Ducati and r6 rider found out over the bridge :D :D )
Didn't take long to find the limiter in 2nd out of a corner and can easily start to lift the front wheel and bounce along the Tarmac if I roll on more than half throttle if over 3,000rpm.
I've still to set the mixtures as its hunting from idle and still a little untidy till 2500rpm.
I'll get around to checking float level too.
Hand on the coils after spirited riding and cool as a cucumber.

17-41 gearing ( soft limit set so far at 9000rpm)
laughter is the best medicine

Rich
Site Sponsor
Posts: 217
Joined: Mon Dec 23, 2013 8:20 pm
Location: Derbyshire UK

Re: IGNITION COIL RELAY MODIFICATION

Post by Rich » Mon Apr 13, 2015 8:04 pm

For Dynas improperly matching to the ignition will be the major factor in making them run hot and ultimately crack. Better primary voltage should lead to increased secondary and a better bang as you have found :D

coxylaad
Site Sponsor
Posts: 1211
Joined: Fri Jan 21, 2011 12:30 am

Re: IGNITION COIL RELAY MODIFICATION

Post by coxylaad » Mon Sep 04, 2017 1:28 pm

Are the stock coils not man enough for the job?

User avatar
epsilon
TRX-Enthusiast
Posts: 4
Joined: Mon Jul 15, 2019 5:13 pm

Re: IGNITION COIL RELAY MODIFICATION

Post by epsilon » Mon Jan 13, 2020 9:24 pm

Hello everyone,
Im happy to find this small cool mod.Im not a Trx owner i have a Tdm 850 2000 so this will
work for me just fine also.
I found this video with a guy doing a relay mode

https://www.youtube.com/watch?v=mqUdxWzZkog

Anybody knows if i modify the relay like the guy in the video will have as a result on stronger spark on the excisting mode with
the ignition coil relay?
Are there any dangers involved,meaning causing damage to a part on the bike?
Excuse my ignorance,electrics aren't my strongest thing.

cobbadiggabuddyblooo
Site Sponsor
Posts: 6809
Joined: Thu Aug 28, 2008 9:19 am
Location: Brisbane,Australia

Re: IGNITION COIL RELAY MODIFICATION

Post by cobbadiggabuddyblooo » Tue Jan 14, 2020 7:10 am

Replace the HT leads while at it.
7mm copper core lead is easily sourced and you can pick up 1m online easily for a couple of $$$
Remove the resistor from the plug caps too and replace with a small piece of brass rod or cut a brass bolt.
Resistor spark plugs are all you need for noise suppression and are standard anyhow on the trx.
Last edited by dicky on Tue Jan 14, 2020 7:38 am, edited 1 time in total.
Reason: Fixed an auto-correct error
laughter is the best medicine

Post Reply