Kill switch a killer?

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You better believe it does. Was holding off on answering while juggling what to do re: ordering the magneto (decided to hold off), but couldn't hold off thanking both Haze, and KC.
I am happy to help when I can bud, I started really documenting things about 70 builds ago and being a 30 year electronic engineer for decades the electronics are not that hard with the right meter and understanding of what does what.

I didn't bring up timing which can be another issue like a fluke weak magnet.
That spinning magnet has to be aligned right to excite the coil at the right time.
I short, it at 1 O'clock on the shaft at TDC and that keyway can slip a degree or too.
 
I am happy to help when I can bud, I started really documenting things about 70 builds ago and being a 30 year electronic engineer for decades the electronics are not that hard with the right meter and understanding of what does what.

I didn't bring up timing which can be another issue like a fluke weak magnet.
That spinning magnet has to be aligned right to excite the coil at the right time.
I short, it at 1 O'clock on the shaft at TDC and that keyway can slip a degree or too.

pretty easy to put them in backwards which wont do much for performance either...

and there was one case of the magnet itself being of reverse polarity?

the sheer beauty of these cdi's is the simplicity.

the magneto creates a pulsed AC waveform.
one pulse charges the capacitor, stores it via an SCR, then triggers the SCR and discharges the capacitor at a specific point on the opposite polarity pulse, a capacitor and resistor setting this point, along with the position of the magnet in relation to the crankshaft... wha? 5 components or so? i forget...


they also suffer from some unexpected EM effects when things like a killswitch is added...

the only reliable way to kill them is to either prevent the cap from charging (bypass it with a resistor) or prevent it discharging (disconnecting gate on SCR)... the standard way of just shorting or open circuiting the wires fries things.... did i say it in this thread already?

shorting the wires creates a high current low voltage in the magneto that fuses fine wires.

breaking the wires causes a high voltage low current that breaks down thin insulation between wires.

you need somewhere for the voltage and current, POWER, to flow...but you also need to dissipate it safely when not required! or things get hot real quick. we do this by adding resistance somewhere.

the old "white wire" magnetos...some ran lights. some got grumpy and refused to run with lights. some refused to run unless the killswitch was held down!
 
pretty easy to put them (mag coil or magnet) in backwards which wont do much for performance either...
hehehe, no, it's all magnet alignment.

they also suffer from some unexpected EM effects when things like a killswitch is added...

I suppose you could put a 1K resistor on one of the kill button wires but I just don't see it as an issue unless you do a lot of riding down hill holding the kill button in because just a second or two will kill the engine at idle, which is only producing weak power as it is.
 
Electronics are my weakpoint. I know nothing beyond the basics. I appreciate very much these explainations and instructions. I have so many ideas...

My solution is to keep an extra stator coil lying around just in case.
 
Good advice to check those readings before I tinkered with anything: the mag was in spec. Was damn hoping, naw praying, that was the culprit. Well, after a ton of reading on the forum here, guess I was damn fortunate the bike ran trouble-free long as it did, seeing I bought it 2nd hand from a perfect stranger: these puppies are such damn intricate mechanisms, systems within systems, all delicately balanced...when they're running, I mean. Which presently mine still ain't.

Got that new mag, two-wire joint, was gonna hitch in on, but that'd be pretty knuckle-headed, you think, till I at least find what's holding me up in the first place, right? Well, counted out the Kswitch and since I'm getting spark, got a new CDI (NGK), and the mag and magnet seem OK, I move on to what..fuel system? The line and such?

I see a bunch of stuff here and on tube on the working and maintenance of the carb. Is that where I go next, cleaning that sucker and what not? Again, can't say enough how grateful I am.
 
OK, I move on to what..fuel system? The line and such?

I see a bunch of stuff here and on tube on the working and maintenance of the carb. Is that where I go next, cleaning that sucker and what not? Again, can't say enough how grateful I am.

start at the beginning.

remove plug. ensure theres spark. check.

remove carb, stuff a drop of fuel down intake.

try to start.

if it starts, revs briefly, dies...its a carb or fuel delivery issue.
if it doesnt even cough, its another issue such as the base gasket leaking, the crank seals leaking, ignition timing etc. if its used, possibility the top ends stuffed. rings and cylinder plating. remove head and have a squiz. head gasket...?

there are only three systems.

you have an air pump, that needs to be sealed.

you have a source of fuel and a way to mix it with the air being pumped.

you have an ignition source timed to go off at the right point in the cycle.
 
After priming via the intake, it kicked liked it was gonna start, than immediately died. Assuming it might be a fouled carb, I removed the filter cover, and the darn filter was drenched with fuel/oil. I mean soaked. And ever after removing it, it still weeped oil to the inner edge. I wipe it away, come back 15, 20 minutes, oil was still collecting in curve of the inlet. Then noticed there were drops of fuel on the floor, and had been there for some time, just hadn't taken notice. So there's no saying how long this puppy's been spitting oil. Could this be at the heart of my problem all along?

Now I see on the net that carbs aren't all that costly, so thought of just buying a new one, but since the whole point of this exercise is educational, I decided to disassemble and clean the thing following the steps outlined here on the forum and you tube and see what I can learn, and maybe in the process just might get my bike to fire up.

One last thing. In unhooking the fuel line, do I drain the tank completely, and start off with a fresh fuel/oil mixture? Or is that necessary. Surely you vets must have a system, cause seems kinda unwieldy uncapping the line, recapping and hooking it up again without making a god-awful mess. Just don't want to get oil into some place maybe it shouldn't be...
 
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I usually just turn off the petcock if I know the fuel is good, to drain tank, I just put a long hose onto petcock and let it drain into a jug on the floor.
 
After priming via the intake, it kicked liked it was gonna start, than immediately died. Assuming it might be a fouled carb, I removed the filter cover, and the darn filter was drenched with fuel/oil.
Just to be clear as to the difference between a 2-stroke and a 4-stroke engine, you can't 'prime' a 2-stroke with liquid fuel.

Spray starter will work, but otherwise most of it just puddles in the bottom of crankcase and you don't want that.

On an NT carb, all the primer button does is hold the float bowl down to fill it after is sits awhile to fill it.
Keep holding it down and fuel is going to flow either out the filter if your carb is tileted back, or into the engine if it's tiled forward.

Is your carb level?

The entire fuel system is gravity based.
You simply need your carb as level to ground as possible to function.

If carb is level then it's just a float bowel adjustment but you can only adjust so far.

One last thing.
In unhooking the fuel line, do I drain the tank completely, and start off with a fresh fuel/oil mixture?
Or is that necessary.
Surely you vets must have a system, cause seems kinda unwieldy uncapping the line, recapping and hooking it up again without making a god-awful mess.
I do all my fuel system work outside, no exceptions as I live here and gas on carpet is not friendly.

You shouldn't need to worry about fuel quality yet.
But for prepping carb removal I like to have it running and just shut off fuel flow until the engine dies.

You can't do that, so just turn off flow, pinch the gas line where it enters the carb, disconnect that and secure the gas line end end as high as you can above the gas tank.

Got a level side pic of engine and carb?
I have a hunch that's your problem.
 
I hope you fixed it by now, m8. But, just in case, I wanted to ask a simple question: have you disconnected the kill switch? My bike was running great and then didn't turn over or would sputter out quickly from start. It turns on the kill switch was malfunctioning and cutting my engine out. If you haven't try just disconnecting the kill switch.
 
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