I put a set of 735mm length 200mm travel MARZOCCHI REP's on my ProX250, very good forks, compression, dampenning and rebound, and if it can handle the 250, it would be even better on a 125-140cc bike
I had probs fitting them as they are not made for my bike, they where 3mm smaller diameter both top and bottom i made alloy sleeves at work, the brakes didnt line up with the disc, i need to pack out the bracket to bring it closer to the disc and and modify the plate the calipers bolt to as the disc on the bike was to bike, so i had to move the setup back a little, an hours work on the bracket and sleeves and the 250 doesnt bottom out like it did with the original forks and feels so much better over bumppy tracks