Engine Trouble Running Essentials- a complete troubleshooting guide

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#21
Yes, if it was installed wrong it wouldn't start at all.
The first one that went bad was 4 or 5 years ago. Had me totally stumped, did not think a magnet would loose magnetism. I didn't find any threads on it.
After replacement the thing ran fine for about 1000 to 1200 miles (Except normal ware and tare, a couple intake and exhaust gasket failures, fuel filter replacement,etc.).
Until it was stolen. (have two listed in "STOLEN BIKES") Have had a total of 4 stolen. (over the last 10 years).
This is the 2nd magnet go bad out of the five personal builds. And this is the first magnet I got that was bad already, new from GasBike.net. Luck of the draw I guess.
Or better yet, BAD luck.
 


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#22
By the way Stoneman; I think I looked like your avatar after plug, wire,
and cap, CDI, and mag coil replacement. And still no spark.o_O:confused:
Darn non magnetized magnets anyway.:(
 

Frankenstein

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#23
Jag you really need to add the paint behind the magneto thing to the list, I've seen it 2 or 3 times before so it's gotta happen often enough to people with black painted engines...
 
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#24
Well had a couple of above freezing days last week, Was able to work in my 10' X 10' work shed/shop. I decided to test the mag and cdi forward and backward.
I also took the best magnet from one magneto mag. and put it in another magneto mag. making sure the poles (north/south) were correct. These are the readings I got.
CDI (20k setting)
Black test lead to black wire.......Red test lead to spark plug cap---6.43
Black test lead to blue wire......Red test lead to spark plug cap---no reading
Red teat lead to blue wire.....Black test lead to spark plug cap---no reading
Red test lead to black wire.....Black test lead to spark plug cap---6.44
Black test lead to black wire.....Red test lead to blue wire and vice versa---no reading (no one shows this test)
Like I said, testing forward/backward and vice versa.
MAGNETO COIL/LOOP (20k setting)
Black test lead to black wire.....Red test lead to blue wire---0.31 vice versa-----0.31
Black test lead to black wire.....Red to ground---0.000 vice versa---0.000
Black to blue wire.....Red to ground---0.31 vice versa---0.31
These tests were done with my FREE State of the Fart Harbor Freight multi meter.
I can't get an accurate AC voltage reading from the magneto with this meter. Can't keep a consistent RPM.
I still have no spark at the spark plug, but it will light up the cheap Harbor Freight spark tester (dimly).
I'm still thinking weak magnets.
 

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crassius

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#25
I've never found a reliable way to test CDI with a meter, For most folks it is best to just try a different CDI. Much more likely a bad CDI than bad magnet.
 
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#28
Don't have a spare. I have only seen 2 others in this town (so far) and I don't know the owners.
Iv'e had a magnet go bad before.
I found a 3/8" shank and turned the engine over with my cordless drill. Got a volt reading of 19.3-20.2 with the meter set 0n 200 ACV.
The RPMs were low with the drill.
 

crassius

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#29
bummer, I'm a repair shop and I've built a tester for the CDIs - not a thing the average rider would do - maybe you can find a set of spares online to use to find which is bad
 

crassius

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#31
I used half a crank in half a case with head attached to allow spark to be seen and timing marks on rotor and case so correct timing can be seen

here's a pic (sorry it is a bit blurry, but camera is crap)

TP-front tester.jpg
 

Frankenstein

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#32
I wonder if you taped that setup you have with the high speed camera in a smartphone if you could get an extremely accurate rep of the actual spark timing.
 
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#33
That's something I was thinking of doing, using case half(s) and crank. I would want to take the connecting rod off the crank. Add a multi grove v-belt pulley and a variable speed motor for variable RPMs. Make a degree wheel out of an old CD/DVD. This would aid in building an AC alternator, like the "mini gen" for testing and working out as many bugs as possible. I like to do as much as possible by myself using what I find to work with. I just don't have a junk engine to work with. Donations welcome. LoL. Anyone willing to donate a junk crank and case I will put it to good use.
I'm building a timing light circuit now on a bread board, if it works Ill make a pcb and a portable unit.
 

crassius

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#34
yeah, I pulled whole center journal out so it spins fairly smooth - I turn it with drill on rotor and use regular car timing light w/12volt battery

you won't have to look long for a dead motor, seems grenading is best trick they know
 

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