gear question on my scooter

[ML-TOYS]

i have this scooter with a 33cc motor. this thing has a jackshaft to make up for the offset from the gearbox on the motor.
the gears run like this
on motor 18 tooth
both sides of jackshaft 18 tooth
whel has 60 tooth
all #25 chain.

current speed is suppose to be 12-15 but of course i need a bit more for the customer.
what would you suggest changing for more top end like another 5mph maybe 7 more. giving an initial kick with foot is no big deal on a gas scooter if needed.

thanks

 

[Doc Sprocket]

I suppose the 50-dollar question is- which sprocket can you change easily? Altering any one of them +/- a couple of teeth will alter the final ratio. What can you get your hands on?

To increase speed, make
*engine sprocket or j/s output sprocket bigger
*j/s input sprocket or axle sprocket smaller

 

[ML-TOYS]

thanks toy, i can get any size i need since i am a parts distributor for scooters. i am removing the rear wheel to extend the air valve so the axle one will be the easiest to get to.

 

[OzFab]

Here's the thing: the fact that both js sprockets are the same size means they cancel each other out so, you final ratio is 3.33:1.

Do you know what the engine reduction ratio is?

 

[ML-TOYS]

Not sure about the reduction ratio, would have to look into it

 

[rmm727]

Is that gearbox a "gearbox" or a "cvt"? They look similar on the outside.