and there is a solution to it as well
1: needle jet needs to be lowered to lean the mixture.
2: if bike cannot idle .. idle also needs to be adjusted. it has affect till 15 % of throttle.
3: pilot jet with smaller hole needs to be installed ..
first two will give satisfactory performance if you keep throttle below 75 % ..
for throttle above 75 % major petrol supply is via main jet and that needs to be adjusted as well.