the why of spark

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anysnail

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some of you might be familiar with my story. i was riding with my new accell super coil on :bike: then i had one strong backfire and now i have no spark. i know i need a new coil and all but i was wondering just one thing. what happened during that backfire that killed my coil? :confused:

i just put in new plugs gapped at .03, it had 7mm accell plug wires, i don't know what a 5ohm cap is but i used the caps that came with the 7mm wires, the coil was well grounded, it was a stock tci ignition to begin with, and i put 135 main jets in.

again i just took it out for a ride, the bike started sputtering then stalled, i dropped the clutch to try and restart on the go and it backfired. why did that kill my coil? :shrug:

i'm just curious is all.
 
What is the part number for your Acell super coil? Some of those coils have a primary resistance which is way too low for the TCI and they fry the output transistor of the TCI. The final blast was probably the transistor blowing open and causing a spark at the wrong time.

If I'm correct about all this, then it was not the coil that fried...it was the TCI.
 
140403s yes that is the one. also pardon my ignorance but what the fuck IS a tci anyway?
 
anysnail,

Well, that particular part number is OK for the TCI. It has a coil resistance of 3 Ohms. I would suggest that you measure the coil primary resistance to see if it is 3 Ohms.

TCI = Transistor Controlled Ignition. It's the factory electronic ignition from Yamaha. A very good system....30 years ago.
 
okay, i need a voltmeter to do that. when i get one i don't know how to use it though. what happens if it isn't 3 ohms? also is the tci something that i have to replace? cuz if it is i'm probably just going to sell the bike. i can't afford to keep putting money into it. i really just wanted something to ride. not something to mess around with.
 
any...,

I think that you are going to find that the coil is OK and your TCI just decided to quit. I would too if I had been working at the same place for 30 years....:D
 
HA! i actually have more time left at my job than i have been alive. i found a tci unit on ebay for $99. is that a resonable price or would i be getting fleeced. also what are the chanced of it quitting again? i really just want to ride man. i think we all know that feeling.
 
any...,

I would wait and check the coil resistance first. I'm only guessing as to what I think the problem is and I was wrong before.
 
don't buy another tci thats 30 years old. just buy a pamco unit and be done with it. very easy install and it works great!
 
well i tested the resistance on my coil and it steadied out at about 1.2 ohms. so i bought the wrong one and it fried my tci. now what?
 
- points, boyer, pamco....putting a used TCI in is asking for problems down the track
 
okay cool! i'm actually kinda pumped to do a whole new ignition system. i much prefer mechanical systems to microchips. which should i go with the boyer or the pamco? i'm leaning toward the pamco with the green monster i hear so much about. then i could upgrade the carbs and the exhaust and i'd have a badass! :rock:
 
Well neither the boyer nor pamco are purely mechanical systems. The pamco replaces the points but still uses the mechanical advance... and the boyer replaces the points and also replaces the advance with an electronic box that does the advancing.

Also, $99 is way too much for a used TCI (unless someone will buy it for that I guess :wink2:) :twocents:
 
well if the dyna is outrageously expensive so i guess i'm going to go with the pamco with the green monster in a few weeks when i get enough cashola. right now it's brokeville in the 'snail household! i guess it doesn't make sense to me to by the pamco non green unit for $26 less and then decide later that i wanted the mean green. besides like i said before i want new mikuni carbs and a 2 into 1 free flowing exhaust. yeah baby.
 
A backfire did not kill your coil. The problem with your ignition system killed the coil and that caused a backfire. Coils work on a principle called "induction". Induction is when a voltage is "induced" into a wire with no physical contact taking place. The energy moves from one place to another. In the coil its moving from the primary winding to the secondary winding. It happens when the primary circuit collapses. So your primary circuit collapsed. It, somewhere, has burned out. At that point the magnetic field in the primary circuit collapsed, went away. That causes the induction and the secondary voltage is created. It runs o the plug and it fires. It wasn't the exact time and you had a backfire. Understand?
 

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