Bought atv was working fine now won’t crank i purchased a new starter and for some reason it melted the starter when I tried cranking it don’t know what it could be any ideas ?

 

First find out if the crankshaft is free to turn by removing the spark plug, taking a case off and turning the crank by hand. If it is, check you got the right starter. The one for 50cc Honda clone engines isn't the same as the one for 90cc Honda clones, or you may simply have got a dud new starter.

 

starter overheats by itself when connected under no load

 

Is it normal for the starter to have case continuity ?

 

There is a small resistance through the starter armature windings, but not much. It will get hot quite fast as it is only supposed to run for a few seconds. However, if it is definitely overheating without being attached to the starter gears there is something wrong with it. Take a look inside. Most common fault is the earth side brush lead not being tightened down.