Break In Engine Head giving off smoke

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cmb271

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Okay, So I'm about 98% done with the build I just need to wait for some loc-tite to cure and go to the hardware store to get some new bolts for the chain tensioner since I somehow snapped one but there's an issue I don't know if I should worry about.

The engine head when it runs for a few minutes tends to give off smoke, I know it's not coming from the exhaust and there's nothing flammable like wires or cables touching it so I can't figure out what it is. The smoke has a interesting smell as if it was burning plastic but theirs no plastic on the head, I've never noticed it on my first 2 stroke build but I did pull the head off and put JB-weld on the end of the studs. Some fuel leaked on it but I wiped it away but it's still smoking, is it burning off imperfections in the metal? Is my engine eating itself (it's not making any grinding or disturbing mechanical sounds) but I'm afraid I might fry the engine before I even get to break it in. I'm using a mixture of I believe 16:1.

I don't know if this is relevant but when I kill the engine via releasing the clutch at a dead stop and it stops small amounts of smoke comes through gaps in the carburetor where it links up to the engine, I don't know if this is just exhaust that didn't escape or a bad sign, I need help guys.
 
You first problem is your using way too much oil, 32:1 is a go-to number even when your breaking in an engine.... When your breaking in your engine giver ell';)
High load full throttle uphill runs
Don't revv above 5k.... This will let the piston rings seat in

I've seen on another thread that your problem might be a piston ring broke, in that case everything I just said is a waste;)
But hopefully it's just a new motor burning something off

Does this engine have decent power?
 
You first problem is your using way too much oil, 32:1 is a go-to number even when your breaking in an engine.... When your breaking in your engine giver ell';)
High load full throttle uphill runs
Don't revv above 5k.... This will let the piston rings seat in

I've seen on another thread that your problem might be a piston ring broke, in that case everything I just said is a waste;)
But hopefully it's just a new motor burning something off

Does this engine have decent power?
If I broke a piston ring, I feel like the engine would vibrate more violently and make distinctive sounds, the smoke is coming from all around the entire head not just the gaskets and openings. I was just going off the manufactures notes.
 
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The manufacturer tells you to do this so if your engine blows up its not due to their instructions.... These engines make so little power that it's basically just idling or its full throttle
That poor little engine has to work 2x as hard for the same power as other engines its size

I think it was HeadSmess that said these engines are just throwaways

http://motoredbikes.com/threads/another-problemo-guys-bogging.47704/#post-413519
 
I tightened the bolts on the head of the engine and the smoking has stopped, I'm going to keep this thread alive so other people could possible benefit from it.
 
Ima having the some problem on my mz 150 etz the bolts are tight after a rebuild. Smoke coming from the head Please HELP
 
Some of the factory paint/dirt/etc will burn off on the first warm ups.

That said, check your plug boot and all bolt holes and gaskets. Clean any oil so you will notice if other leaks open up.
 
Smoke coming off of the heads of these motors is not uncommon. When running hard you can see temps of 450f, that'll burn off just about anything. Hell, I've yet to have a sparkplug boot last longer than a couple of rides before melting.
 
You may possibly be running on the lean side extreme lol. Or running some ultra cheap spark plugs boots.
 
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