Hi:  I had a case of what was probably vapor-lock of some sort but wanted to check to make sure the symptoms fit the bill: Hot august day, at least hot for bay area standards.  Bike was parked in the sun at work until 2:30pm, and started right up and I rode off.  It felt a little weird I have to say... but I thought maybe it was just having to stop and go in traffic and me not hitting my gears right.   seemed to right itself once I was on the freeway.. crossed the bay bridge and just a