I am joining the dark side. A bone stock NSR50 is too long in the tooth to keep up with the 4s MiniGP bikes. Our spec class puts the NSR with the Honda NSF100 and Kayo GP 125.
My donor bikes are: 2004 Honda NSR50, 2002 Honda XR100
A little off topic, but do you happen to have a stock XR100 head laying around Brian? I was planning to do the Kitaco 100cc kit, but I haven't decided yet. --L*64