Ive had few WR125s in the past and have been a long time member here. Ive been riding other bigger bikes but couldnt stay away and picked up another 2013 Wr125 a couple of months ago. I thought Id share my recent experiences getting back into a smaller bike again Bike was a low hours bike owner by an older gent (even older than me) I rode and it felt pretty ordinary . Big bog and weak power but ok at top . It was all orginal and still on its original piston. Played with the power valve arm - didnt do anything . Richened the needle height that helped a bit. Put the RM needle in with a #5 slide and put on an old 39mm Mikuni I had with the RB designs divider plate mod and hey - now we are talking .. Big power increase in the middle to top end . Jetting 460 main with 40 pilot . I would possibly try 470 main but dont have one . Put a new piston and rings ( Id say 10 hrs old ) in with a .3mm base gasket and now its feels great. Compression was down at around 120 and now at around 155 Felt it was maybe a tad rich down low and tried a 32.5 pilot and still pulls well. Less spooge. Had quite a few rides and really loving this bike . The top end power is surprisingly strong - even though I've had wr125s, 144s , 165s . I love the feel of 125 motor size. Its sounds great and gets a lot of comments. The handling is just fantastic . I really feel so confident on it and that means I ride it a lot faster in the tighter tracks than say the ktm 350 , fe450 or te250 2t , wr300 I have been riding . The steering is so good and I can push it in the corners much harder. So much fun. Ive put a stiffer rear spring on and all it really needs now is possibly shorter gearing - say a 52 rear. I will post any other big improvements .