New doesn't always mean good. Your "new" carb could be one of those that "fits your machine" but doesn't work properly. Sounds like it's running too lean and getting too hot. Instead of a new carb I find it better to clean and rebuild the original piece. If you were able to get the machine to run, then you can probably figure this out yourself. Get a repair manual so you have the correct specs for the machine. Your spark plug could be the wrong heat range, the jetting in the carb wrong for your location.

 

You are getting ripped off - he was just too lazy to rebuild the original carb and got you to buy a cheap replacement carb - now the pipe running red hot is an indication of too high an octane fuel, old fuel or a lean condition in the carb - it has nothing to do with the crankshaft unless the timing is off and that can be corrected. You need to find a different mechanic!

Also, it's not abnormal for a single wall head pipe to run red hot for a few inches - typically will only be seen in subdued light like inside a garage - get out in the sunlight and see if it can be seen - my CRF250 runs the head pipe bright red for 8 to 10 inches away from the exhaust port and it perfectly tuned - you don't see it outdoors, but it is very noticeable indoors.

 

Thanks everyone I've been searching and searching for answers I believe he makes a living off of messing people over cause we clean the carburetor and that's what got it running but it didn't run like its suppose to I dont know