bore

That in and of itself does not cause relibity issues. Low quality parts, poor machining, crappy assembly do.

The biggest killer is operator error. Lack of maintenance, unwillingness to follow jetting,testing advice are the biggies.

FYI, only bore engine enough to clean it up, nothing will be gained by maxxing it out.

Right, boring does nothing to gain power. You can do pretty much anything you want to these engines, as long as you have a good builder and care for it properly. Get a good port job and head mod, and it will make a big difference

My motor is stroked, bored to the limit (because of necessity, not for power) and ported and it will start on the first or second kick just about every time with no issues while riding. I agree that reliability will depend on the quality of the parts, the mechanic, and how the operator maintains his ride. IMO reliability is in the hands of the rider (testing for air leaks, properly jetted, clean air filter, etc...).

Definitely get the cylinder ported and the head re-chambered. Those two items and a good pipe with proper jetting will net you over 30-32 HP. That's double your stock output. A really thrilling ride that makes you wonder how that "Little Blaster" your sitting on , does it. The reliability is there too. These little air cooled 195cc engines are seriously "de-tuned" at the factory. Lots of power left on the table if you know where to look. The combustion chamber shape in the head is one of them. You can do all this and still run oil injection if you desire. I do and have never looked back. Pre-mix or oil injection... both work equally well. I hope this helps. By the way...
WELCOME ABOARD!