What is this?
 

Please see attached. Can someone tell me what this screw does? So I have two of these Taotao 125's -- one of them has the screw, and the other one has it missing. Actually - it's more of a threaded rod-- the end of the screw is actually a nut. Not sure if I'm supposed to thread the nut all the way to top or what. Can someone advise?

Thank you!

From what I see, it looks like that should be a stud for the exhaust flange. Got a picture looking up from the bottom?

Okay, took a picture from the bottom side shooting up for you. I think the screw is to the left, being covered by the black pipe. Looks like I'm missing a matching one on the other side, and then that flange is hanging down as well?

Thanks again!

Yes, exhaust stud missing, looks like there could be a bit of it still in the hole, if so it is a job for a specialist, getting broken studs out and re-threading holes is one of the most awkward and skilled jobs a mechanic has to do. A local motorcycle repairer or general engineering shop will be able to tackle it.

Ah, got it. Thank you. So, we are attempting to fire these up for the first time today -- will they operate with this missing?

Thanks again!
Shane

You can, but don't run them too long. Not good for it to be sucking up the extra air. Bad for the valves.

yes good way to kill the engine. I would definitely leave that removal to the pros. Getting a steel stud out of a alum casing can be a real PIA.

Thanks for your help everyone! My buddy and I were able to get both of these up and running this weekend, including getting the exhaust mounted securely!

Cheers,
Shane