It may have gotten hot, but it could be simpler. Many bikes don't generate enough current to keep up with ignition use until 2000 rpm or higher, especially older bikes. The Bridgestone 175s have notoriously poor charging systems, so check compression before getting too worried. Depending on the state of your battery, it may have just gotten low on voltage and no longer fired the plugs well enough. The excess smoking is curious as overheating a 2-stroke shouldn't make it smoke any extra unless it got so hot (into the 400+ range) it damaged the right side rotary valve center seal and pulls oil from the transmission.