Jetting and gearing for 125cc gpx motor

[minibiker]

Was wondering what gearing should i use for my bike i have a 125cc gpx race engine, high comp piston, race cams, whopping power, 13,000 rpms stock motor. What gearing should i use since i ride at frankston mx track which is full of turns and corners which is sort of a tight track, ive got a 13tooth front and 41 tooth rear atm, also i have a 26 OKO carbi with factory jetting was wondering what jets should i buy to give it some more performance??

 

[my67xr]

what settings is the carby on now, eg needle clip, mixture screw, and what size pilot and main jets.
how is the bike running? no bogging, no flat spots, spluttering etc?

changing the jets will only make more power if it is running bad,
the carby needs to be tuned correctly to suit the motor it is fitted to.
so if it is running good at the moment, fitting bigger/smaller jets may make it run worse.

Carby Tuning


how is the gearing now at that track?
you could try a 14tooth front sprocket on it, it may make the bike a touch easier to ride, with less wheelspin etc

do you have an outer rotor kit on it?

 

[motovert24]

i'd use a 15t front for frankston, on my oko26 i had the jetting as 38/100

rear sprocket doesn't really matter, 1 tooth off the front is the same as 3 teeth off the back sprocket i think,

on my lxr i had 14t front and 39t rear, changed it to 15t and seemed abit better. was a 184 tho. my gpx feels like the gearbox ratio is alittle better so i reckon 14t or 15t would be fine with whatever rear sprocket you use

 

[minibiker]

The track is alright but tight and short runs and full of turns, Was wondering what else to do to gain some more power?