Repowering ignition coil

[bigskyforever]

I have been fighting poor spark on my old TX project all summer. Sooty spark plugs, poor idle, poor performance. I can now remove and reinstall my carbs in my sleep. At this time I am only using the kickstart, so starting it has kept me in shape. At this time I have not converted to electronic ignition as finances are a little tight right now.(too many projects) Having gone through spark plugs way too often I decided to change my game plan.

I removed the resistor type plugs and threw them in the garbage. I found non-resistor plugs at my local Honda dealer. Same plug as the old 450 two cylinder.(black bomber)
I removed the resistor cap and put non-resistor caps.(I could care less about the neighbours electronic gadgets)

I then wired the coils  directly from the battery through a 4 pin relay and also installed a relay harness also available at a local automotive supplier.

Basically the kill switch now controls the relay and you install a heavier wire from the relay to the coils, getting a much better power load to the coils. This will be the best money you will ever spend on your TX project!!!!! 

It now starts way better, less spitting sputtering, stronger idle and way better performance. 

If you test the voltage at the battery and test the voltage at the coils and you have an original wiring harness you will most likely have a drop in voltage. On my TX the engine would only start well if I had just charged the battery. When battery voltage was below 12.8 it would sputter spit and finally start. Voltage checks at the coils revealed 11.8 volts or less. 
I believe that the information out there informing us that the TX were subject to weak coils is not quite correct. The coils are originally wired from the kill switch with a 18 or 20 guage wire which can't possibly bring enough current at the best of times.
I can not take credit for the wiring idea. 
I found a vintage motorcycle site which discusses issue with old controls etc. and has a schematic on how to install the relay.
Do a google search«repowering ignition coils»  this will bring you to : wgcarbs.com  Let me know if any of you try this out. 

[retromech]

glad you are going in right direction-well done, will just point out I have had 2 instances where automotive 4 pin relays connected directly to the battery have engaged themselves when unattended, resulting in 2 events which led to an extreme fire hazard, only prevented by the situations being discovered accidently.

[bigskyforever]

I have placed a 10 amp fuse in between the power at the solenoid and the 4 pin connector to make sure there is limited amperage, which should reduce possible short or fire risk. Did you use a relay plug harness in connection.

More detail of your two events would be appreciated.

[retromech]

Hi,I am away for 2 days when I return I will give the full details

[farmrjohn]

I suspect the coils still could be a contributing factor, especially once they warm up.  I initially had that warming problem, and replaced the coils with a set from MikesXS.  That helped, but I'm really happy with the electronic conversion I did.  The relay/direct to coil wiring is a highly recommended mod on the XS-650 forum, but I went with the electronic conversion mainly because I suck at getting both sets of points timed and gapped properly.  Once warm the condenser could also be a factor, another system the electronic conversion eliminates.

[bigskyforever]

farmjohn

What electronic system did you end up using? Are you still using points as a trigger? Or did you use a Pamco .
I have a good gl1000 coil I will be using to fire my next TX project and will use only one set of points.
I am considering using the points as a trigger with the dual output coil. The wasted spark will also contribute to a cleaner burn. The second set up points will be set and condenser will be available should there be some technical issues with the igntion.

[retromech]

Hi, Regarding the coil repowering, as I said I have encountered 2 problems with 4 pin relays connected directly to the battery, both were factory fitted to their respective cars (in the 1970's).firstly a relay installed as part of the starter inhibit system on an auto trans car, when sat on the sales lot overnight the relay closed, energising the starter and cranking the engine, also taken from the starter solenoid is a wire that feeds the ignition coil 12v when cranking (when not cranking coil is fed approx. 9v through a resistor) resulting in engine starting, leading to damaged starter motor, associated wiring overheating, also damage to starter gear on drive plate, car found with engine running by patrolling police officer, who called my boss out in the middle of the night !!second incident was my own classic car
which is kept in storage, I went to my garage one day, stood outside as I could hear a buzzing sound, opened door to find horns blowing, both horns and wiring very hot, luckily caught in time, relay again at fault. I am sure technology has moved on since then, however it is not something I will forget, hope that explains my (slight)concerns.

[bigskyforever]

Thanks for your comments. Firstly I am not powering a starter as this unit is kick start only. I thank you for your feedback and experiene but I do not believe I have any further concerns at this time.

Thanks.

[retromech]

That's fine, I am sure the quality of electrical components has improved over the years and repeats of these type of events are unlikely, just that once you have experienced these type of incidents you do not easily forget them, I would however think your comments about not having concerns are correct as the risk is minimal.

[farmrjohn]

Sept 21, 2015 20:07:58 GMT -5 bigskyforever said:

farmjohn

What electronic system did you end up using? Are you still using points as a trigger? Or did you use a Pamco .
I have a good gl1000 coil I will be using to fire my next TX project and will use only one set of points.
I am considering using the points as a trigger with the dual output coil. The wasted spark will also contribute to a cleaner burn. The second set up points will be set and condenser will be available should there be some technical issues with the igntion.

Bigsky-

I thought I had replied, but I guess not.  The electronic system I used is a composite Toyota/GM/Honda/Yamaha as described in my DIY ignition thread.  Prior to finalizing that I used both points to drive a Ford TFI ignition module, which in turn powered the dual fire coil I'm using now.  That also worked fine, was easy to wire in, and was not that expensive.  Both methods did not require any non-reversable changes to the existing wiring but used the existing connectors.  The Ford TFI would not even require opening up the points unless you wanted to check the timing and gap.