Well-Known Member
Hi Guys, i have a aprilia sonic 50

My setup is :

standard crank
standard piston
standard cyl head
Giannelli race pipe
mallossi variator
mallossi gear up kit
standard clutch and springs
3.5 gram rollers
standard belt

The bike pulls away brilliant gets to about 30mph and completely loses power, takes quite a while to get to 40mph but once at 40mph picks up again and rockets to about 62mph top speed, I cant understand why there a loss of power after the accleration?
Up gear kit is a little worn but nothing mager.

Any1 have any ideas or advice as to what the loss of power could be?

Thanks Guys !!!

Last edited:
Advertisement - register to remove this


Well-Known Member
I have the same problem. but my is very slow from 0-10kmh then fast to 40kmh and slower again to 50kmh and then faster all the way upp to top speed :S.. and i have a Yamaha aerox. with yasuni exhaust ::)


Well-Known Member
@ Luke:
Try heavyer rollers

@ Blue Ninja:
Oh bollocks, now i'm in trouble i have no clue what part it is in english :p
But it's a little screw inside you're Carburater.
Try getting a bigger one.
If you pull of you're air filter and get to you're carb. Get the carb off then there are 2 screws in you're carb (if correct) unscrew those.
You should end up with a little container like thing and the rest of the carb.
In the rest of the carb if you look towards where the screw's were pointing there is a small but pretty fat screw.
If you look good enough (and if it isn't worn off) it says a number on it (like 70 or 80 all the way going up to 120) Remember that number adn try finding a bigger one.
It's probably called a jet or a sprinkler or something of that nature.

And luke is just heavyer rollers try 4 grams or 4,5 or try mixing should work fine.
Advertisement - register to remove this