Scooter Shack is now a read-only archive. Over 20 years of scooter knowledge (2006–2026) is preserved here. New posts, replies and accounts are closed.
Hello, Im new here
I have derbi senda sm 49cc 2007 and i've got problem with it...
The problem is that my Senda go only 60 Km/h
i have blocking things (tell me how its called,thing that blocks moto to 60 km/h cuz my english is poor )
and how i should remove that blocking thing ??
blocking thingy hehehe , you mean your senda is restricted and you would like to know how to de-restrict it.
a couple places you need to look into, first is lifting the rpm restriction on the cdi , Anthea do a unlimited CDI , that will allow the bike to rev a lot higher .
Exhaust, your stock exhaust is somewhat strangling the power the engine makes , changing this to a unrestricted exhaust will unleash even more power, BUT if you do this you MUST also have your carb upjetted to allow more fuel into the engine. more fuel = a bigger bang = more power = more speed.
once the three bits above are done , exhaust -cdi- jetting , you can tinker with your gearing ratio,
your engine will have a front and rear sprocket, a bigger front sprocket on the engine and a smaller rear sprocket on the rear wheel will extend your gear ratio overal. i would say no more that two teeth extra on the front sprocket should do you fine any more will put a lot more strain onto the engine and you dont want that to much.
Welcome to the scooter shack and your english is fine
gonna hedge its a stock 53 on rear, thats what they used to come fitted with as standard 53t rear and i think it was a 14t front
I3ence would need to count the teeth on the front sprocket im gonna say its either a 14t or a 15 tooth.
i also know derbi did sell a race front sprocket in a 16t form factor.
if he is running a 14 tooth front sprocket he could gain a couple extra mph moving to a 15t front sprocket, but i think a 16 tooth is just to much for the motor to pull , you would tend to see a 16 front and a say 43 rear used if you have a 70cc kit fitted as your producing a good amount of horsepower to pull that final ratio
i remember some models had a sort of restriction with the rear sprocket, the gearing makes it totally stupid to ride, massive rear and tiny front sprocket, if you go down the rear by about 3/4 you should see better power.
the exhaust is the main restricter on sendas, either crimp out the empty chamber bit, or buy a tuning one.
)