Can't Get a Spark... Again...

GoldenMotor.com
Jan 21, 2015
610
25
18
Portland, Oregon
So after getting my bike running for the first time, it ran for 5 days, about 30 miles each day, then on the 5th day, as I was going up the mountain my house is on, the motor died. I thought it was cause I was going too slow, so I turned around, pedaled downhill, and it started again. Got home, but the engine made some funny noises, like it was not getting a spark every time. Then next day I tried to start it and can't get a spark. So far I've redone all the wire connections, replaced the spark plug, regapped it, replaced the boot, taken the cover off the magneto to check for stuff coming loose, disconnected the kill switch, reconnected the kill switch, replaced the wire, checked the connections again, and put the old wire back because the new one didn't work and I knew the old one did (and tried to start it after every step). It still won't spark. I have no idea how to isolate the problem, could be anywhere from the magneto to the plug, what should I do? And if nobody can help me solve it, then does anyone in the Santa Cruz area have a good 12-gauge I could borrow so I can shoot the thing a few times?:-||
 

brown

Member
Feb 1, 2013
239
16
18
Bloomington IL
Everyone who owns a China Girl motor should buy a spare magneto coil. I prefer to buy the 2 wire variety. They go bad all the time. If you get the coil wet they seem to go bad even quicker.

To test the magneto coil get a multi meter/volt ohm meter and read the ohms of resistance between the blue and black wire.

Put one test lead on the blue and the other on the black. set the meter up to test ohms on the 2000/2k scale. Ohms should be between 300-400. Zero resistance shows the coil to be shorted (bad). Infinite resistance means the coil has a broken wire(bad).

If you don't want to mess with testing just try a new coil. They coils are pretty cheap and available everywhere including Ebay and Amazon. Better to buy ahead so you don't have to wait for them to be shipped.
 

fatdaddy

New Member
May 4, 2011
1,516
4
0
San Jose, Ca.
Everyone who owns a China Girl motor should buy a spare magneto coil. I prefer to buy the 2 wire variety. They go bad all the time. If you get the coil wet they seem to go bad even quicker.

To test the magneto coil get a multi meter/volt ohm meter and read the ohms of resistance between the blue and black wire.

Put one test lead on the blue and the other on the black. set the meter up to test ohms on the 2000/2k scale. Ohms should be between 300-400. Zero resistance shows the coil to be shorted (bad). Infinite resistance means the coil has a broken wire(bad).

If you don't want to mess with testing just try a new coil. They coils are pretty cheap and available everywhere including Ebay and Amazon. Better to buy ahead so you don't have to wait for them to be shipped.
OH NO!!! NOT THE COIL. Yeah bro 99.99 out of 100 times if theres no spark, IT'S THE COIL. About $10 most anywhere. If ya get one with the white wire on it, CUT IT OFF, or at least cap it. DO NOT use it for anything. If the coil is weak sometimes you can run it downhill and get it started, but prolly not just pedlin.
fatdaddyusflg
 

fatdaddy

New Member
May 4, 2011
1,516
4
0
San Jose, Ca.
Are they available in any stores (not online)?
Also is there a better coil that won't go bad?
the short answer is,, nope. online, unless you know someone like me that runs a motorized bike shop. They are ALL made in China so you KNOW it dont get better than that.laff . So nope again, Not really a better one to buy that I've ever found.
fatdaddy.usflg
 

fatdaddy

New Member
May 4, 2011
1,516
4
0
San Jose, Ca.
Dont let em get wet, EVER. And never use the white wire for ANYTHING. Where you at in California? If yer close, Maybe I can help ya get one.
fatdaddy.usflg
 

bluegoatwoods

Active Member
Jul 29, 2012
1,581
6
38
Central Illinois
So how can I stop them from burning out if that's the case?
There's not much you can do except to make sure that it's water/weather proof. The magneto cover, that is. But the good news is that these things don't burn out every day. But they die on occasion. And a few die quick. Don't know why, other than poor materials/construction.

I suppose you need to go to one of them big box stores and buy yourself one of those pre-paid VISA cards. Then you'll be able to get parts online.

You'll also want a cheap Volt/Ohm meter. They can be had for as little as $10 or so.

Then go to the 'search' box at the top of these pages. Type in something like 'magneto troubleshoot'. You'll get links to all sorts of threads on the subject.
Here's an example:
http://motorbicycling.com/showthread.php?t=1056

Once you've diagnosed spark issues a time or two it won't be any real trouble for you anymore.

Best of luck with it.
 

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
I ALWAYS carry a spare coil in my kit-bag. I have had too many go bad in the past which left me stranded miles from home to NOT make sure I always have a spare. It also prevents you being off the road while you wait for your replacement. Whenever you blow out a coil, order another. In any case, I have FINALLY gotten to the point where I think I know how to properly protect these sensitive coils: use spray-on PlastiDip to double-coat the coil-body, and make sure that when you reinstall, use Permatex Form-A-Gasket #2 to seal off the case...I spread it on BOTH sides of the standard gasket to make it water-tight. I also glop some into the wire-hole and plug going to the CDI (outside AND inside that white fiberglass protector), and over the screw-holes once the case is sealed. I've even gone as far as spraying PlastiDip on the effected areas of after I'm done. I've gone many months now through adverse weather conditions and leaving my bike in torrential downpours without loosing a coil. I HAVE had unprotected coils go bad VERY easily in the past, like riding after a rain-shower. The hole where the coil-wires exit the case is pointed towards the front-tire. If you don't have a front-fender, rain-water easily gets sprayed up and into that hole...even a little moisture can destroy your coil.

PS: I notice you seem to have pushed your new engine pretty hard; are you sure you're broken in properly? Without an ohm-meter, it's hard to definitively claim a magneto issue. Be sure your compression is good (check the torque on your head-bolts), and try not to push the engine too heavily until you're broken-in.
 

bluegoatwoods

Active Member
Jul 29, 2012
1,581
6
38
Central Illinois
....... I have FINALLY gotten to the point where I think I know how to properly protect these sensitive coils: use spray-on PlastiDip to double-coat the coil-body, and make sure that when you reinstall, use Permatex Form-A-Gasket #2 to seal off the case...I spread it on BOTH sides of the standard gasket to make it water-tight. I also glop some into try not to ........
This is pretty interesting, Kioshk.

If you can spare the time, would you write this up with more detail? Before I'd try it I'd want to have a better notion of just where to put the plasti-dip and where to not put it. Things like that. Pics would be good.

If you wrote it up in a separate thread, then I can see a 'sticky' in the works.



And concerning spare parts; When I finish a build I immediately order another new kit. This becomes my parts stash. They're so inexpensive that it makes sense. (there are 2 kits sitting in my attic right now. I have plans for one. And #2 is spare parts.)

I've always thought that this would be a good idea for anyone and not just newbies.