Try using proper 2t gear oil or at least ATF,they are a lighter weight oil & will fling off the plates easier,
XLD probably works better on an mx bike than a trials bike because of the higher revs that the clutch is pulling
I had a young guy bring me his late model Yam YZF250 complaining that the clutch would not disengage properly(ie drag),I took the bike for a spin & sure enough when you pulled in the clutch the bike would keep on going full steam ahead,even dragging the rear brake would not make it break loose.
I quizzed the owner on what type of oil & how much he put in as he had recently serviced it & that's when the problem started happening,He had used the correct oil & the correct amount as per the owners manual, So I thought I would have a look at the plates,I drained the oil out of the motor & out of the oil tank(dry sump innit),when i saw the amount of oil in the tray i knew i had found the problem,like about twice the correct amount,the owner had drained the sump & not the oil tank & then refilled with the correct amount stated in the book if you done it properly & drained both,the result was the clutch swimming in oil,not able to fling it off making it drag,refilled with the right amount & brand new again