Clutch wont fully disengage?

[adidasguy]

So, have you removed the right side cover and cleaned the clutch plates ?

[Joolstacho]

I've just run my bike with good (expensive!) 15weight oil, after a number of flushes & test runs using cheap 10w oil.
The gearchange/clutch now seems nowhere near as nice with the 15w. Surprised that the change to a slightly heavier oil weight has made such a difference. (the engine has certainly been 'round the block a few times, so it's not a matter of tight clearances). I've just done a top-end rebuild.
Just an initial observation at this stage... I haven't put enough k's on it yet to know for sure.

[ohgood]

I've just run my bike with good (expensive!) 15weight oil, after a number of flushes & test runs using cheap 10w oil.
The gearchange/clutch now seems nowhere near as nice with the 15w. Surprised that the change to a slightly heavier oil weight has made such a difference. (the engine has certainly been 'round the block a few times, so it's not a matter of tight clearances). I've just done a top-end rebuild.
Just an initial observation at this stage... I haven't put enough k's on it yet to know for sure.

Make sure it isn't over filled

[prmas]

In the hot weather I use 20w50 and find that both the clutch and gearbox work much better. Both have a much more positive feel. In the cold weather I use 10w40 or 15w40. I also change my oil every 2000km with a filter change every 3rd time. None of my machinery has ever seen dirty oil. 

[dinkydonuts]

In the hot weather I use 20w50 and find that both the clutch and gearbox work much better. Both have a much more positive feel. In the cold weather I use 10w40 or 15w40. I also change my oil every 2000km with a filter change every 3rd time. None of my machinery has ever seen dirty oil. 

That could actually be too short between oil changes unless you ride really hard. Modern oils can stand up to a lot of abuse.

[prmas]

With respect, as a qualified motor mechanic with 43 years experience and 25 years running my own workshop I can tell you that there is NO substitute for clean oil/coolant/fluid. This is not the right thread to go into details now but I am happy to discuss it with you further if you wish. Suffice to say that we have an expression in the trade: OIL IS CHEAPER THAN METAL !