Knocking noise!?!?!

It could of ran hot .but the exhaust skirt is on the piston.blasters are famous for brakeing of piston skirts.from many things.1 over heating from running lean.improper brake ins also u said the shop u had work done didnt install the oil hose to carb? Could of blown from that lack of oil.if a skirt broke inside your cylinder may need a bore job to clean it up and check lowend crank bearings if did brake im not trying to scare u but only way to find out is to tear into it and look.very easy remove tank, carb,and remove 4 bolts on jug.give us feed back on what u find.
 
Well it's going to the shop today to get checked out... Hope everything's fine, if not how much could a bore job cost with a new piston?
 
Idk on priceing thats the shops call but rough guess 200 or so could be cheaper.let us know what all that knocking was.i hope it wasnt something bad
 
I would ask for an itemized list of everything they do (and everything they did before) to your Blaster and go over the items with the shop rep until you completely understand what they did. Don't let them try to blow 2-smoke up your a$$.

Make sure whatever they do to it that you start it up and run it while you are at the shop so you and they can see if it works. If it is doing exactly what you hired them to fix in the first place, you want to make your point right there in the shop so everyone within earshot knows about it, especially if they try to charge you for their shoddy work the first time around. Do not be shy about getting what you want...shops are masters of trying to talk customers down to cover poor work ethics.

I may have overlooked this but did you mention if your oil injector is hooked up and functioning with oil in the reservoir, or are you specifically mixing your oil and gas?
 
well the guy at the shop told me un hooked the oil line from the carb purposly becouse he mixed a little 2 stroke oil into the engine but idk im not shure i just told him to leave it alone next time and get the job done...