Hi Don,
This might sound like a silly question, but are you using the correct width inner tube for the tyre?
My original inner tubes were meant for 26" x 1.5-2.1" tyres, but when I put some 26" x 2.35" wide tyres on the bike I experienced fast deflation of the tyres from tiny thorns etc. because the inner tube was being excessively stretched to fill the inside the wider tyre.
Since I fitted the correct sized tubes
(26" x 2.1-2.5") filled with Slime, I have only been inconvenienced once from a puncture after a 1/4" wide sharp piece of stone sliced through both the tyre and the tube.
Fortunately it was on the front wheel, so I was able to wheel the bike on the rear wheel for the last 2 miles of my 7 mile ride and was also able to use the motor to assist on steep hills.
This was definitely the longest wheelie my bike has ever done.
Whenever I have had to repair a puncture in the past, I have always tried to identify the precise part of the tyre where the puncture occured. I always mark the valve position and direction of the tyre before removing the tyre, and then I mark the inner tube direction as it is removed.
I then inflate the tube to locate and clearly mark the air leak and then place the tube against the tyre matching the valve position and the direction markings to locate the puncture area on the tyre.
I then carefully inspect and feel for any sharp intrusions in that area
(inside and out) and make sure that any broken thorns or small pieces of metal, glass or stone etc. are carefully removed before refitting the repaired tube. In some instances, I have used superglue to repair the split in the tyre and placed a rubber patch on the inside of the tyre to help prevent future problems.
Always make sure that the inside of the tyre
and the outside of the inner tube is completely clean and dry prior to assembly, as even a tiny piece of grit in between the tyre and the tube can eventually result in an unwanted puncture.
After installing a repaired tube, I always inflate the tyre to the maximum stated pressure and ensure it is holding pressure and seated correctly on the rim before refitting the wheel and lowering the pressure to my preferred ride pressure.
Unfortunately, it's impossible for me to say what has caused your particular puncture, but hopefully the above information will help you to locate the cause if it happens again.
The only guaranteed way of avoiding punctures altogether is to fit
solid tyres, but I have not been able to find any in a 26" x 2.35" size that would fit the narrow GM rims.
Alan 
