How do your gears feel?
Can you shift as smoothly as before?
And can you tell if it's somehow overheating?
(do you feel unusual heat in your legs?)
In this particular model the correct type and
amount of oil is crucial and it MUST circulate
perfectly at all times since it's air cooled only.
BTW you should always change your oil while
boiling hot (careful), this way it's thinner and
takes with it all kinds of nasty deposits; get a
magnetic plug
Exactly what kind of oil did you use anyway?