blacknblue, your story matches what I have found in my limited experience with motor builds but also what I have read. Running them WFO after a 5-10 minute warm-up period seems to make the motors run stronger. Maybe it will slightly reduce the longevity (maybe) but as you said most everyone on this forum is looking for performance over longevity anyway.
When I was younger I rebuilt the bottom and top end on a bored and stroked, fully built big valve 500cc 350X motor. I was attempting to break it in slowly but it developed an air leak on the intake and it would run lean and when this happened it would rev up to the moon before I could grab the clutch, brakes, and kill switch. Of course it took going through this several times before I figured out what the problem was and it scared the **** out of me that I was accidentally screaming a brand new motor that I had just spent thousands of dollars on. Well after I got the air leak fixed that motor pulled VERY hard and is the strongest quads I have ever ridden. A year or two later I cracked a case on that motor and bought another low hour 500cc 350X motor and even though it had the exact same bore, same stroke, same cam, same pipe, bigger valves and even a better FCR carb it never pulled as hard as the one that was literally broken in at WFO. I bought it used so didn't break it in myself but I did tear the head off and inspect it before I ran it and it was indeed a very low hour bored and stroked motor but didn't run as strong as my other one.
Current quads:
- Honda TRX 400EX - fully built 416cc motor and full XC racing setup for fast trail riding and hill climbing
- Kawasaki Prairie 650 - work quad for around our property and main quad for the wife to ride
- Suzuki LT80 - kids quad
- Honda TRX 350RX - my old school hybrid MX quad from the 90's that has a 250R chassis with a built 350X motor and has now been converted into a XC setup
Previously owned several other sport quads and a few trikes over the years.