Engine Trouble Starts for a few seconds then dies.

[Louie]

Hi,
My bike has been running well for 100 miles. Yesterday, it died just at the end of my 3 mile trip I make every day. 4 hours later, it was fine on the return trip. Today it died midway through the trip and wouldn't start for the return trip.
When I drop the clutch, it turns over but dies out after a few seconds, and if I disengage the clutch it dies immediately. Im running 32:1 btw
Here's what I've tried:
I opened up the carb and cleaned it out (was clean anyways)
Opened up the head and checked the rings. (they're fine)
Tested the magneto (getting 370 ohm blue to ground)
Didn't try leaning it out with the c-clip because I've been running it at the same position for a while, although the spark plug did seem a little wet. This could just be from all my failed attempts to start.
I did notice that the exhaust pipe isn't completely flush against the exhaust manifold. Not sure if this could be the problem.

What else could it be?

EDIT: Just took off the exhaust cap and it had quite a bit of black oil in it. Not sure what that means.

 

[Frankfort MB's]

EDIT: Just took off the exhaust cap and it had quite a bit of black oil in it. Not sure what that means.

That's probably your problem....
Try and start the bike w/0 the cap on, probably clogged up the exhaust.

Don't worry, there's nothing wrong with the oil in the exhaust all 2 strokes do it

 

[Louie]

Tried doing that, same problem.

 

[Frankfort MB's]

Might also be a fuel lock on the gas tank, try to start bike W/O the gas cap on

 

[Louie]

I don't think it's that. When I took the carb off to clean it, fuel came gushing out of the fuel line because I forgot to close the pet cock. It's hard to tell if the problem is fuel or electrical because I get a little of both when I try to start it up.

 

[Louie]

Also, just tested the CDI resistance. Getting 7.4 kOhms from CDI black wire to spark plug cap. I believe that's about what it should be.

 

[Louie]

New NGK B6HS plug. No change

 

[crassius]

not turning petcock off when parked can fill motor with fuel - either keep it running until it clears out (may take a mile or so) or take out plug, unhook CDI and pedal motor till it all blows out

indication that this has happened is oil in muffler & excessive smoke when it starts

 

[gary55]

Sounds like it should be running fine. Don't hate me for mentioning these two things cause I know it sounds dumb, but is the nut on the choke lever tight? Sometimes they get loose and vibrate the choke closed when riding. How about the connector at the plug end of the wire. Sometimes they will break but still work intermittently. The only reason I bring these up is cause it sounds like everything is good.

 

[Louie]

Tried taking out plug and unhooking CDI and pedaling around for about 5 minutes. Nothing. Also I tested the plug and did get a spark. Not sure how bright it should look but i did see one.

My choke is fine, and I'm not sure how to check whether the plug connector is good.

I did notice that riding around with the plug removed actually sounded like the engine running, so maybe I'm confusing that sound for getting a spark when I try to start it. What could cause a weak spark?