[Darren69]

My S4 runs the same and gets hot, it was even worse before I fitted an oil cooler (which it didn't have as standard like the S4R). I also find the side air scoops help when on the move, they force cool air onto the rear cylinder.

The rectifier will get hot under the seat and will probably burn out before too long. Its a stupid place to have it really. I moved mine so it gets cooling air and fitted a big metal heat sink, its been fine since.