New Brozz250 smoking
 

Is it Normal for smoke to be coming off of the exhaust near the motor on a new bike? It also is cutting off on its own after a few minutes of running

It's normal to get some burn off when you first start a new china bike.

I would pop the gas cap and see if it's a venting issue.

perfectly normal, that's new engine!!!

Yeah, it's normal for a bit of a smoke show on brand new bikes. They are coated in a protective oil film for transport.

It's normal for the oil and paint to burn off when they're new, but it's not normal for them to shut off on their own. Check for loose intake bolts or a vacuum leak. That will cause the exhaust to get hotter than normal and make it overheat and quit. It's probably ok, but wont hurt to check.

Did you adjust your idle screw to about 1,400 RPMs ? Does it just go from a nice smooth idle to suddenly dying like someone turned the key off, or is it more like it gradually looses RPMs, and dies ?

I did adjust the idle screw after it seemed warmed up and had it around the 1500 mark. Definitely shuts off like someone turned the key. I’m going to check the bolts on both sides of the carburetor to make sure they are not loose tomorrow based on the potential vacuum leak mentioned.

I would bet it has more to do with spark than air,or fuel , if it just dies suddenly from a smooth fast idle. I don't know what the temperature is like were you live,but these motors get hot especially stationary, and idleing . Electronics have a way of acting up when exceptionally hot.

You also need to gain access to the idle mixture screw and tune it. You will have to remove the plug that is covering it up. I'm sure it's like most of these bikes, the idle mixture is probably set way to lean. But before you go nuts trying to tune it, adjust your valves. More than likely set with little to no gap.

Iam with Jerryhawk250 on this. If your valves are too tight this is what would happen.

I did actually adjust the valve lashing before ever starting the bike. I followed a "Joamon" doc i found somewhere that listed .003 for break-in. Its possible maybe I didn't do it right since its my first time doing it but basically followed the steps I saw online in a few videos.

As an update I pulled the spark plug (i had replaced with an NGK ) and found that the gap was high so I reset the gap to match what the Brozz manual had and it seemed somewhat better and stayed running without cutting off.

My next thought is the fuel/mixture screw on the carb - anyone have any pictures or know of a video that shows how to modify it - mine is either capped or broken so no screw driver will fit.