Sluggish starts after new belt install

[del la sol]

So the belt on my Zuma snapped, got a new one, exact same yamaha part # as what was in it. Before if you were at a dead stop and gassed it wide open, in say some grass, dirt, or gravel the bike would instantly take off spinning the rear tire, it was alot of fun. Now with the new belt if your at a stop and gas it wide open it just sits there for a second, and then slowly takes off, once you feel the clutch engage or whatever, you can feel something like engage, at like 2-3 mph it accelerates great and i'd say my top speed is definetly up a little. Last night we put a new belt on my friend's identical stock zuma and his got the same bog off the line with the new belt. I had read that a stretch/worn belt will cause your top speed to go down, and I know theres often a trade off between top speed and acceleration so could it be that a stretched belt while hurting your top speed can actually improve your take off? Or is it more likely we did something wrong on the install, I didn't really see where we could even do it wrong its so simple, but I'm not a professional.

[scootertrash]

I'd say a worn out belt would ride lower in the pulleys, giving you the effect of a lower gear ratio at take-off.
A new belt is going to be wider, which will ride higher in the pulleys, raising your ratio, giving more top speed.

[XPS1210]

how are the rollers?

[del la sol]

they look to be in good shape as far as my amateur eyes can tell, but i've got a couple new sets of different weights i'm going to try out and see if it helps any

i do alot of offroading and hill climbing riding, before at those really low speeds i'd be having pretty good power to pull me, now when i'm trying to crawl up a hill or get through some sand or mud and not moving at a decent speed its stuck in that boggish range and will barely get along

[zumasterling]

I think you should Terrence keep the new belt with the problems and you run his nice and seasoned belt. My kevlar belt better be in soon.