Wanted to bring this discussion back up to the top.
Rode out to Savannah, GA last Thursday and back on Friday from Va. Beach. It is right around 1000 miles round trip.
When I left the temps were in low 30s with light snow for the first 200 or so miles, then it warmed up to around 40. The trip back was a little warmer (low 40s). Didn't have any issues with the clutch on the way down but on the way back (around 350 miles from home), I noticed the clutch acting "weak", once I pumped it a few times, the pressure would build up and everything was back to normal.
I had this problem two years ago while riding across Texas and Oklahoma in July (temps well above 100), and I attributed it to the heat and air in the clutch hydraulic system (did the lean the bike to the right and pump the clutch trick to get the air out). Once I got around to the cooler leg of my trip (Idaho, Montana, etc.) didn't have any issues. Had the bike checked out when I got home and I was told everything was normal. Can't blame the heat for the latest episode. Didn't see any leaks by the slave cylinder back then or this past week. The fluid level is still normal (it is the red kind).
I will be leaving in June on a 12K mile 30 days trip, I am thinking about having the clutch slave cylinder replaced so I don't have to worry about it. How hard is it to DIY and what am I looking at $$ wise?
The bike is an '09 GS with 39K miles on it, BTW.
1970 Honda SL100 (my 1st bike in 1972)
1972 Yamaha Enduro 360 (loved this bike)
1977 Yamaha RD 250
1978 Suzuki 250TS
1982 Kawasaki GPZ 550
2007 BMW F800ST
2009 BMW R1200GS (Current)