I gave two ybr 125 both have 150 kit and 16t front cog. Recently back from 3000mile trip across Spain where the extra torque from 150 cc and a set of gears that exploit that made holds far easier and 60mph cruising easy enough, third gear acceleration in the midrange with these mods is very different....really ! 150 kit was £45 16t cog £10 , no brainier. Both bikes have high profile trail tyres fitted which will also raise the gearing ever so slightly. Put these bikes together for the trip with my son who is new to bikes. Iv messes with bikes for 40 years and I would say thus is the best value for money change Iv ever made to all the bikes Iv messed about with. Would recommend to all those who have respect for the solid, cheap, reliable ybr