How do I stop the spark?

[b.walker5]

Come on now, you all know you HAVE to plug the wires some how or you will let all the smoke out!!!! It is the smoke after all that really does the work in all electrical systems.

Absolutely.... It's known the world over and taught to every apprentice that the Blue Smoke is the basis of electricity and everything from that point on is about how to stop it from leaking out.

[clcorbin]

That's like saying turning off your light switch at home is going to hurt the transformer on the pole. This sounds like the same people that tell you it will burn up the electrical on a bike to jump start one from a running car.

Electricity isn't like a liquid. Volts aren't going to pool and dam up behind the coils. Just like it won't hurt to have the electricity behind your light switch wating to be turned on, (Grounded) it doesn't have your coils charged waiting for the potential to spark. Your TCI will send the signal to the coils.. and really doesn't care if it fires or not after that.

So.. warm the motor up first, pull all the plugs, hold the throttle wide open, and with a compression tester installed, crank away for a few seconds or until the needle quits moving.

Won't hurt a thing.. but make sure you don't leave a wire attched to a spark plug right next to the hole. It may spark and give a nice little flame-thrower demonstration... but even that is a slim chance.


Tod

Actually, it is POSSIBLE to damage parts of the ignition system doing this. The problem is break down voltage. The voltage on the primary side of the coil starts to rise (quickly!) when the transistor opens the ground path to the coil. Normally, the voltage on the secondary (which rises even much faster than the voltage on the primary) will get high enough to fire the spark plug. At this point, the voltage stops rising on the primary and in fact collapses.

Things are a bit different when you don't have the plug attached. The voltage starts rising, but there is no way for the power to be dumped into the spark plug, so it keeps rising on the primary much higher than it normally would. Eventually, the coil magnetic field collapes and the voltage drops on the primary.

During this very high voltage event on the primary, the switching transistor has to resist this reverse voltage. The higher the voltage gets, the harder it is for the transistor to resist it and it is possible for for it do do some minor damage every time it tries to fire. Eventually, it can fail because of the tiny damage done over and over again.

Will it fail the first time you do this? Probably not. Will it EVENTUALLY fail? Probably. Will it decrease the life of the transistor? Probably.

It's your bike, so do what you want. I don't see any reason to risk doing some damage to the electronics on the bike, even if it probably won't destroy it right away. Besides, all you have to do to kill the spark is disconnect the two bullet connectors (one for each coil) that provide 12v power to each coil. You do have to pull the tank off, but that takes all of 30 seconds to do.

[petejw]

I agree with clcorbin as well, its one of those
things you could do a thousand times and nothing happens,
yet do it the first time and it could blow the tci,
it doesnt hurt or take any longer to earth the lead or the plug onto the head,
if earthing the plugs on the head you can check out
the condition of the spark at the same time.

i would especially do it this way with after market coils
with the higher voltage they put out.

and is more critical on eloctronic ignition in later model cars.


but each to there own.

[Pat Kelly]

jump starting the bike with a car

At one of the CA rallies I watched as LoHo jump-started his Suburban with his XS. Was this bad? Both bike and car are fine last I saw.

[3Phase]

At one of the CA rallies I watched as LoHo jump-started his Suburban with his XS. Was this bad? Both bike and car are fine last I saw.

It depends. Was the XS running? It could have seriously damaged the Suburban's electrical system if he tried to jump start it with a running motorcycle.

Maybe he just got lucky!


Regards,

Scott

[oseaghdha]

You guys are way too complicated!

Just jump it across the solenoid with the key off.

duh.

[Fix]

I have a bit-bucket I use when I have to disconnect a network cable. Otherwise the internet could spill out.

[randy]

Right. And don't forget about something to hold all those dropped tokens. You can hang 'em on a ring for safekeeping..

This is getting too silly even for me

[cywelchjr]

Hey, save up the contents of the bit bucket for the next time you want to put someone to sleep, just use the ether you collected from the disconnected cable.

[T99Ford]

clborbin IS right. The primary circuit of the coil being left on is the problem that most manuals caution against when recommending grounding the spark plugs. THis is the same reason that it is not a good idea to leave a key turned to the "on" position if the engine is not running (use the acc. postition).
This was more of a concern with breaker point ignition, though, when there was no transistor to regulating the primary ground path, and it was luck of the draw whether or not your points would be open or closed.

For a compression test, though, I just crank it the way it is and don't ground them. I suppose there is the safety issue involved also, as I have set more than one lawn mower on fire this way

[3Phase]

Just jump it across the solenoid with the key off.

duh.

That only works on bikes with no ballast resistor. On '78 - '80 bikes, the Red/Yellow wire from the solenoid goes to the TCI and runs the coils without the ballast resistor. It'll still spark.


I remove the 4 wire connector from the TCI for the times when I'm working on the bike and I don't want it to start but I need to use the starter. Compression testing isn't one of those times.


Regards,

Scott

[randy]

If the key is off it won't spark the TCI needs power to do its voodoo

[3Phase]

If the key is off it won't spark the TCI needs power to do its voodoo

You're right, I didn't write that very well, did I? Bleh... I was referring to the time TheWiz had his starter solenoid stick. He couldn't shut off the engine and the starter motor was running.


Regards,

Scott