I put a 72cc BB in my wife's 2013 Agility because we also live in a city with hills, Marquette MI. But, I put 8 gram rollers in the variator keeping the rpm's down to let the engine live a little longer. The BB torque pulls most of the hills 25-30 mph & still gets 43ish top end. I have a long post with following my, trials, troubles & mods, with specs at the end of the post.
On the topic of losing power after 2/3 throttle. Your bike has a CV, Constant Velocity, carb. The hand throttle opens a butterfly which controls about the first 1/4 of the throttle. After that first 1/4 there's a slide that opens & closes, off of a vacuum signal, which controls the velocity of air through the venture. That's probably why it feels the way it does to you. My bike did have part of the diaphragm folded over which limited the movement of the slide. The diaphragm pulls the slide up & down depending on the amount of vacuum I mentioned. The bike would only go about 5mph up hill & is why I put the BB in it. Again it's all in my post.
Agility 50 / 2013 Agility 50-72cc
« by JayAre on May 12, 2015, 01:39:43 PM »