I learnt something useful this week. Ensure the coolant level in the rad is sufficient so that the thermostat is in the liquid. It is located at the top so a low level of coolant means that the fan doesn't kick in. My mate's Evo nearly seized due to this. Luckily, I noticed steam coming from the overflow. The fan wasn't coming on even though the engine was extremely hot. Shows how critical pre-ride checks are!

Whilst I'm on, also pull down the rear brake piston protective rubber next time you check the bike over. it collects a lot of grit which remains after the finer particles of mud are washed out.

Dave

Agreed. I couldn't figure why the fan would not come on. It's been cold so wasn't too worried. The rad seems to have to be filled right up to the top of the filler neck. Then the fan operates normally.