New CDI, Spark Plug. WONT START!?! Help!

WildWillis

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Local time
12:55 AM
Joined
Nov 8, 2016
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8
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Australia
Hey, I've recently bought a cheap Chinese motor and rode around for a bit no drama's.
I saw oil leaking from the bottom of the bike at a substantial rate before changing the ratio to 20:1 to fix the problem.
After that I hit the road no problems at all. until.... My bike simply would not start, so I pedalled really fast and it started up but then would stall if I went to slow. I attempted that various times and after doing it probably 2 times it just would not start at all.
I replaced the spark plug, No results
Replace: CDI, No results
A few days prior I tightened the cylinder head bolts and heard a crack. not thinking it was anything I proceeded.
Checked Magneto and seems fine but I cant test it without an altimeter unfortunately. I pedal release the clutch and can hear the engine turn over but with no spark. It almost sounds like gas or air is escaping when I do it.
I took the cylinder head off to look inside but had no carbon. When tightening the bolts It cracked about 2.5cm in the middle. After that I've given up and I'm not sure what to do.
Please Help!

I checked the air filter, tightened carburetor etc.
 
Hey, I've recently bought a cheap Chinese motor and rode around for a bit no drama's.
I saw oil leaking from the bottom of the bike at a substantial rate before changing the ratio to 20:1 to fix the problem.
After that I hit the road no problems at all. until.... My bike simply would not start, so I pedalled really fast and it started up but then would stall if I went to slow. I attempted that various times and after doing it probably 2 times it just would not start at all.
I replaced the spark plug, No results
Replace: CDI, No results
A few days prior I tightened the cylinder head bolts and heard a crack. not thinking it was anything I proceeded.
Checked Magneto and seems fine but I cant test it without an altimeter unfortunately. I pedal release the clutch and can hear the engine turn over but with no spark. It almost sounds like gas or air is escaping when I do it.
I took the cylinder head off to look inside but had no carbon. When tightening the bolts It cracked about 2.5cm in the middle. After that I've given up and I'm not sure what to do.
Please Help!

I checked the air filter, tightened carburetor etc.
I guess we know you need a new head. Probably a gasket to cause it sounds like you over tightened it. You should invest in a in. lb. 1/4" drive torque wrench. 8mm head bolts torque at 162 in. lbs. Roll the bike with clutch engaged, with plug out, wire attached to plug, and side of plug grounded to engine to check for spark. Much easier if you have a way to get the rear wheel off the ground. Chances are that it was the head the whole time, and your spark is just fine.
 
If you said it ran until you idled down, it might have just been the idle rpm set to low.
 
Come on guys the guys got a 1 inch long crack in the center of his head that might bear some attention.
 
Come on guys the guys got a 1 inch long crack in the center of his head that might bear some attention.


Whoops, I should have read the whole thing.

Ya, might want to get some duct tape.
 
definitely replace the head and when the new one comes in plane its mating surface flat so it seals good.
order a new head gasket while you're at it.
But I think the lack of running (before he cracked the head) was due to a bad stator coil or bad electrical contacts at the screw heads (because that is the ground path for the spark)
 
He may very well have a bad stator,and it sure wouldn't hurt to order one even if it's not the issue. Spare parts always come in handy. Ha actually says that a few days prior to the troubles he was tightening the head and hear a cracking sound, but thought nothing of it. I thought possibly the crack was minor but grew causing the later problems. Coincidentally last week I not paying attention to my torque wrench setting I over torqued a head and herd a light ting. I didn't investigate it, put the bike on the stand and fired it up. It ran fine so I took it for the test run. Got about 1/8 of a mile and boom! the head split completely in half. It didn't hurt the engine so I replaced the head, but it left a hell of a mark on my ego.
 
definitely replace the head and when the new one comes in plane its mating surface flat so it seals good.
order a new head gasket while you're at it.
But I think the lack of running (before he cracked the head) was due to a bad stator coil or bad electrical contacts at the screw heads (becuase that
 
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