The days that I noticed this were really hot days in the summer, probably pushing 100° outside. As far as if the temp gauge rises going up hills withour the AC on, I'm not really sure, I haven't taken it up any steep grades in a while. I'm not super mechanically inclined but I wasn't really...
I have a 1987 R10 with the stock 305. My temperature gauge wasn't working properly so I put a new sending unit it and everything seems good now, it will climb to 210° at the middle of the gauge and stay there. But if I cruise down the highway, no traffic and with the AC running, it will...