Kill switch a killer?

Status
Not open for further replies.

Rockin_Roll

New Member
Local time
3:48 AM
Joined
Jul 19, 2015
Messages
9
Location
East US
The four months I've been riding my 2-stoke Skyhaw bike has been, as the Craig list's seller said it would be, a complete blast! I have not a bit of worry or moment of regret -- well not exactly, but that's nothing to do with the bike, and for another post. But this is for something that is indeed cause for worry and concern. Two, three months into the almost daily riding, maybe 5 to 10 miles a day at most, the kill switch went dead. Just wouldn't work anymore. I'd press the button, only after coasting to an almost dead stop, but the engine would still be purring pretty as ever. I'd gently release the clutch and she would halt, pretty as you please.

Couple of weeks ago I'd riding along and the engine/motor just stops. Bike keeps going with the momentum, the engine stops as if somebody pulled the plug. And it wouldn't start, after twenty or so attempts. I noticed the coil leading from the CDI seemed a bit frazzled so I ordered a souped-up CDI from bikeberry, along with a new 3-point plug (I know there's a bit of a row about this, but I have other types as well}. Took the bike out today and she still won't turn over. I hear and feel the poppin' compression, but no, just like before she won't turn.

I notice on You Tube some jokers with otherwise good working bikes are often stalled on starting because of the kill switch. Tho it's never made clear just how that keeps an otherwise good bike for turning over. Just how does that happen? Could that be at the root of my problem? If so, how did the bike continue to perform even after the switch was a goner. I'd like to order another one, but I sure would like to know if there something else I should look at which might be at fault before having to spend another week waiting for something which may not be the cause at all, get me? Appreciate any insight from you good folks.
 
kill switch is useless, get rid of it...

if you use it to short the cdi wires... you get a low voltage but a heavy current, fuses the coils wires.

if you use it to open circuit the cdi wires... you get a high voltage low current through the coil...flyback effects etc cause a super high voltage that destroys the insulation between the wires in the coil...

and if you have the type that runs a white wire, and thats hooked to the kill switch... certain death of magneto incipient!

its not that hard to pull in the clutch, stop with the brakes and just stall the engine out by dumping the clutch... far more reliable.


you can fit a decent killswitch to a jag or home made cdi that works in a different area and bypasses all these troubles...
 
As to what your actual problem is now, I think the coil itself is fried. Not the black box, the coil under the engine cover. Get a multimeter and google how to test for continuity, then test the coil under the engine cover. That will tell you for sure.
 
Hats off to ya'll both. Wealth of info in all that, enuff for me to at least began to see some daylight. Get back here soons I have something to tell. Again, my thanks.
 
Butterbean, finally got the multimeter, checked utube for how to use the darn thing, but must confess I'm unsure just what I'm supposed to be testing. You mention the coil under the engine cover. Is this one of the wires protruding from the magneto? And further, if in fact the coil you speak of is kaput, just what will I be replacing? The coil? The engine? Sorry but as I say, I'm a complete Kramer when it comes to anything mechanical. Appreciate it if you could be just a bit more concise, and, goes without saying, your help and patience is invaluable. My deep thanks, my friend.
 
When you get a new magneto (you will) get the newer type that only has 2 wires on it. The older ones had 3 wires, and were of lower quality. Wire a simple toggle or rocker switch into the blue wire (I fabbed a box onto the CDI to hold it) This kills the power to the ignition without shorting it out, making the whole thing much more reliable. When changing the mag, make sure it's sealed up good (RTV silicone) moisture will short out the coil.
 
Thanks, PH. Do I take it (not to put words in anyone's mouth) that is what is meant by the above suggestions of the coil being possibly burned out, the wire from the magneto? (I'll order it right away and be sure to order the newer type as you suggest.) Not trying to second guess anyone here, just trying to understand what I'm doing and why. Thanks for your time.
 
The mag is pretty delicate on these engines, vibration used to kill them. The older ones with 3 wires were made pretty sloppy, the new ones are much more reliable and vibration proof. Leave the tie strap on the coil, then make sure the air gap around the magnet is even. There are many older threads on this forum about them to read up on if you don't understand their function. Another weak point on these is the plug wire. They screw into the CDI box. Replace the stock wire with a good quality automotive wire (I use Accel spiral core) and use a good spark plug (NGK B6HS) These mods will greatly improve both reliability and performance.
 
This is pretty easy once you know how it works and how to test parts.

...Two, three months into the almost daily riding, maybe 5 to 10 miles a day at most, the kill switch went dead. Just wouldn't work anymore.

A kill button is just a momentary switch.

Push it and it makes a connection between 2 wires, in this case the blue output and black ground magneto coil output wires under engine cover.

In short, no voltage from the winding the magnets spin inside makes it out so, no spark, the engine dies.

Virtually every magneto ignition system uses the 'output shorting' way to kills the engine and won't hurt anything.

It is passive, if the switch breaks it simply can't make the connection and you ride on.

..the engine stops as if somebody pulled the plug.
I noticed the coil leading from the CDI seemed a bit frazzled so I ordered a souped-up CDI from bikeberry, along with a new 3-point plug

Coil leading from the CDI?
Pictures of your wiring would sure be nice as shotty wiring is pretty common with kits like this.

The magneto is a coil inside the engine cover that has a magnet in that spins with engine RPM inside it and makes a low voltage in the coil with the blue (hot) and black (ground) wires as output.

The CDI (Capacitor Discharge Ignition) module has timing circuits and big step up transformer coil to make a big momentary spark with one wire to the top of the spark plug.

The other connection for the spark plug is the engine itself as a ground which goes all the way back to magneto coil whose black wire ground is attached to engine case.

Any break or shot in that full circle circuit will prevent spark.

I sure would like to know if there something else I should look at which might be at fault before having to spend another week waiting for something which may not be the cause at all, get me? Appreciate any insight from you good folks.

My troubleshooting procedure is simple these days.

Set that Bikeberry junk aside and start with what you had.

Disconnect all the connections.

Ohm the black magneto (in the case) wire to a head bolt, it should read a dead short.
If not, check the ground tab on the magneto.
Note:
The new skyhawk CDI's have no white wire, ground is the lower connector but it has a wire from it to ground.

Old style mags with a white wire have a tab out of the mag that solders directly to the mag base and they can come loose, just hold it down and re-solder.

Ohm the magneto from the black and blue wire, 320-380 ohms is ideal, an open or dead short means a bad magneto.

Ohm the CDI in the 10K-20K scale.
Red+ meter probe to CDI black wire.
Black- meter probe to the spark plug cap.
You should get about 6.9K ohms.

If not it could be a bad wire or cap.
Unscrew the plug wire at the cdi, use pliers or even cut it off and dig the junk out if need be and do the same test above again to the cable screw on the CDI.
If that works get a new wire and plug cap, if not you have a bad CDI.

If all of that is good there is only one thing left, the magnet.

That was indeed the problem with this repair on a new build with a 2014 gasbike.net front page engine kit.

When you pull the 4 bolts out of the magneto mount it should slam itself against the magnet, I mean to the point where it is hard to even get your first bolt in.
A weak magnet that lets you move the mag around pretty easily is not strong enough to create a spark which is what this repair had.

Magnet replaced, problem solved and that repair was done.

Once you know you have spark it's fuel or compression, and in your case probably a case full of unburt fuel, ride it around with the plug out and clutch out so you can blow the junk out.

Hope that helps.
 
Hope that helps.

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. For the first time since I've been riding, I feel like I have a half a** understanding what I'm sittin' on. Can't tell you how much this has added to the whole experience. Now I understand the pull for serious bikers/riders and race buffs--something that goes a bit beyond the kinetic sensation of moving through the wind. I bought one of those cheap analog multi-meter at first, but then went back and got what I shouldn't got from the git-go, digital. I got rid of the old cdi when I got the new one, so am unable to pix the frazzled connect I mentioned (a serious tinkerer throws away nothin' -- I'm learning). Soons I get the time and space to follow KC's instruction, I'll report in. Again, thanx so much.
 
Status
Not open for further replies.
Back
Top