Clunk and Lunge into 1st..

Hi All-



..long time viewer, first time contributor.



I recently got my urban assault vehicle out for spring. After a few weeks of riding on last fall's oil, I've put in a fresh quart of 20w-50, my usual summer oil lo these last 3 years. Starting 'er up and shifting into 1st, the clutch chunks something awful and the bike lurches forward (occasionally stalling). Idle rpms slow, and it feels as if the clutch is not fully disengaging. We are having 60 degree weather up here in Minnesota. And as stated, I have used 20w-50 oil plenty in the past with no troubles whatsoever.



REMEDIES I'VE TRIED

-- adjusting free play in clutch cable

(thinking maybe clutch wasn't fully disengaging)

-- allowing the engine to warm up for 5 minutes before shifting into 1st

(thinking oil viscosity needed to thin w/heat.. 60 degrees out)

-- holding in clutch for upwards of 20" before shifting

(thinking oil viscosity was keeping clutch from disengaging as easily as usual)

-- slightly backing the bike while shifting into 1st

-- blipping the throttle while shifting in..

(..read these somewhere)



None of these nor combinations thereof have worked. I'm not opposed to simply trading out the oil for a 10w-40 or something, but am confused.. as 20w-50 has worked so well for me in the past.



Any feedback or advice appreciated



2001 TW200

42 tooth rear sprocket

11,500 miles