Can I throw my two cents in and I don't mean to come off sounding like a jerk or anything...
Your bike looks freaking great. Seriously it looks fantastic.
I think you have a fantastic story here. I mean not only is it interesting in that it makes people THINK about the fact that these other items besides just the piston need maint., but it shows them "Hey bearings, linkage, lube etc...".
I think the 144cc kit is fantastic because the YZ125 is one of the most popular bikes made. So it gives owners with roached cylinders an alternative - and not only an alternative but a BETTER alternative because it gives it more power and makes it easier to ride and certainly that creates better lap times.
I also think that whether or not you put a pro on it or a rank amateur is 100% unimportant. It's an interesting article - look at some of the tests they do in the magazines such as "budget bikes" they talk about their build but they rarely race them! Those articles happen all the time - why? Simple not everyone can afford a $10,000 race ready thumper.
What you did here was fun, exciting to those reading it because they wanted to see it happen and well it developed "interest" and so that makes it a 100% success.
Does this bike have to win nationals? No... can it race against 250F's at the local level? Maybe with a good rider on it -but- it also shows you can build something, have fun and not spend a trillion dollars by building a bike you already have.
Now here is an FYI. IRONICALLY The first ever motorcycle test on the internet was called "CAN AN OLDER BIKE BE COMPETITIVE and it was a KX500 that was built up exactly like this YZ125 was... From bottom to top from scratch. This story reminds me of that one very much...
Good job guys... and the first line said I hope I don't come off snotty... That was in ref to some saying this was going to HURT if you didn't build a race winner... not every bike is a race winner, ask KTM and the guys riding 350SX thumpers... what you did do was post a WINNER of a story for everyone to read and follow along with. And that is what this is all about.
Peace, Mikeee P