Engine Trouble Engine wont start? TROUBLESHOOTING GUIDE

jeffuehrer

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Joined
Apr 12, 2010
Messages
119
I recently had an issue with my electrical. I was cruising along and then all of a sudden I lost power and then rolled to a stop. I could tell it wasn't mechanical because there weren't any loud noises. I did a quick field study. Checked spark plug, plug wire, cdi connectors, inspected inside magneto and drive sprocket compartments. Then I peddled the last mile and a half home. I already knew it had no spark. When I got home I swapped out the spark plug with a known working one. Nada. Then I swapped out the CDI with a known working one. Nada. Then I swapped out the magneto and voila! I also swapped out the magneto wire compartment plug from the rubber stopper type with the one on my spare parts engine which is threaded and screws in for a nice tight fit preventing any moisture from entering the compartment. I could see a visible difference from the non-working magneto to the working one. The non-working magneto had splotchy patches on the arms. The working one looked brand new probably because of the threaded plug. So I would recommend everyone get a threaded plug.
 


Big Red

Active Member
Joined
May 14, 2011
Messages
1,172
Yeah Jeff, 9 times out of 10 thats the problem when talking electrical. This may seem anul, But I've been trying FOREVER to get people to call the parts by the proper names. The MAGNETO is that spinning MAGnet that turns inside the COIL. What you actually replaced was the COIL. Thats the thing that is COILED with copper wire.
Everybody knows what you were talking about, Everybody calls the coil a magneto. even the suppliers call it a magneto coil. But if you were having an ongoing problem it helps to be as precise as possible. Like I said, Sometimes I get a little anul, Sorry.
And yeah, Keeping water out of the coil case is a GREAT idea. I've even used sillycone or RTV Blue to make sure at times.
Anyway, I'm glad you got it up and running. A broke bike just ain't as much fun as a running bike.
Big Red.
 
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Joined
Mar 4, 2013
Messages
56
I read through the list of things a dozen times..I think I fouled the plug by holding it to earth or the carby is flooding from a fouled needle its running me up the walls..Iv broke 2 pull starters and resorted to kick starting or tying and wearing myself out to get so mad I could throw it..I just wanna hear her BBRRAAPPP so bad..It had spark..couldn't confirm gas and whats the compression suppose to be???
 

Big Red

Active Member
Joined
May 14, 2011
Messages
1,172
Before I can even TRY to give you any advice I gotta know what ya got. 2 stroke, 4 stroke, china girl, Morini, hua sheng, Honda, ect, ect, ect. The more info I have the better I can help.
Big Red.
_______________________________
IT'S YOUR BIKE, BUILD IT YOUR WAY.
 

Fabian

Well-Known Member
Joined
Sep 8, 2009
Messages
4,522
I just wished i could be there with you because i would have the engine running within 2 minutes and if not it would be running within 15 minutes.
 
Joined
Mar 4, 2013
Messages
56
I need to know what the compression test should show and the proper torque specs for the head..Studs finger tight?I know to tap the tops to make sure they are seated good but should I torque them as well?
 
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Joined
Mar 4, 2013
Messages
56
I just wished i could be there with you because i would have the engine running within 2 minutes and if not it would be running within 15 minutes.
I wish you could be here too ..It has to be something simple It was smoking when I turned it over this morning..I'm going to get a fresh gallon on gas to mix up the right ratio keep this oil stuff for cleaning.
 

Big Red

Active Member
Joined
May 14, 2011
Messages
1,172
I've used up to 8 Oz of oil per gallon on a BGF engine for break in, (cause I don't really trust BGF engines.) Smoked some but still ran OK. And just put yer finger over the plug hole and see if it blows yer finger off. Even with a little head leak it should still run.
I kinda went through yer other thread to. I did notice that you were using the white wire for the kill switch. NEVER do that. It's a direct short to the coil and can, (and sooner or later,) Will destroy it. From the kill switch, One wire to blue, one wire to black. Don't matter what way. But you might have already shorted your coil enough to weaken it. A weak coil will get a spark, just not enough to start it.
If yer getting air, gas and a GOOD spark it should start, or at least POP a little. I think it's a weak coil. I've been through this a million times. LOOKS like a good spark, but WILL NOT START. So like I said, I think I'm gonna vote WEAK COIL on this one. CDI's go bad sometimes too, But 99 out of 100 times the coil goes bad first.
I always recommend going through the checklist before throwing money into parts. You've already done that. Coils are $12 or so, cheap enough to take a chance.
So when you install the new coil and get it running let me know. (Coil, Not Magneto)
Big Red.
 
Joined
Mar 4, 2013
Messages
56
Iv took the magneto magnet off..And one way it just wont go on,Id have to file it for it to slide over the key....Im pretty sure its TDC the way I have it.
It might be the coil,But the white wire wasn't to the killswitch I just cut it because I heard thats the thing to do..I was getting a pop every now and again early but now its just turning over..Iv tryed pouring some gas in the head and still no back fire or anything to think its firing at all..
 
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