Clutch not engaging after oil change

[Supafly_MX]

I have a 92 cr125 and recently my sprocket had a leak so i pulled the sproket out and replaced the seal. While the sprocket was out the oil leaked out so when i put the seal in and put the sprocket back on i filled about +/-600ml of new car oil castrol 20W40 not realising that there was oil inside the motor.
So when i took the bike for a test ride the clutch didnt want to engage, the lever was soft very soft, but when the motor is not running and i put in first gear and rock the bike the clutch lever comes hard(normal). And when the bike is in motion (riding it) the clutch works through all the gears. Its only when i come to a stop and put in in 1st gear. I drained all the oil out and put the correct amount of oil ,Castrol 20W50.
Whats wrong with my bike ?

Could it be the thickness of the oil. It used to run perfectly before, why now ?

Please help
Cheers

Supafly_MX

 

[john3_16]

Go 10W40......20W50 is a little heavy for a 125cc motor...I had the exact bike back in 1992 and put many hard motos on the bike as well as lots of practice....10w40....AVOID energy concerving oils....

If your clutch is worn from lots of use the type of oil won't matter....Time to change clutch plates..

 

[Supafly_MX]

The clutch was replaced not long ago.