So it means approximately your bike has covered some 19000-20000km.
Well Honda CG 125 usually vibrates but if the vibrations have increased than before then check and tighten all the nut bolts of the bike.
Adjust drive chain tension and oil that.
Do get the spokes of wheels tightened.
Clean the air filter properly.
If plug is not changed till now then change the plug.
Adjust the valve(tappet) clearance.
Adjust Air fuel mixture.
Use some quality engine oil. But that must be wet clutch safe and api grading no more than sj.
If the problem remains unsolved then check the Push Rod's, Rocker Plate, Cam Followers, Cam Gear.!
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