Old cg 125, gear ratio changes, what to do?

[tahx]

Hello people. i own a cg 125 2005.

i had recently changed the clutch plates and straight out of the garage, is seemed to run fine.

the problem started from next day, i noticed the gear ratio has changed. for example for 2nd gear, i used to get the end of gear RRRRRRRR sound on like 30/35 kph, now it starts revving on around 20 kph. so while on the first day , i could get like 50-55 kph on 4th gear, now im getting around 40.

is it the clutch plate or something else. please help me out guys! TIA

[Hassan1991]

ASSALAM-O-ALAIKUM
What's the condition of your bike's engine and carb?
Clutch plates can't cause this problem until they are worn-out.

[tahx]

walaikum assalam.
the bike engine is in avarage condition, so is the carb. recently i overhauled the carb myself following the manual. it seems to work better than before now.
There is no chance of clutch plates worning out, i changed them 2 days ago.