Jack,
I understand why you have fitted the flap to keep the hot air from the radiator from your intakes.
I'm kinda curious what effect the flap has on the temperature of the oil in your oil tank?
My $3.99 oil dipstick/thermometer (converted meat thermometer - told you I was a cheapskate!) shows my oil at 190 degF after a decent journey.
(The dipstick/thermometer I had on my Valk used to show 210-215degF but that was straight into the engine casing sump)
I see on your pics that you don't have a oil tank thermometer on Spike, do you have access to a infra red thermometer or any other way of finding out what temp your oil is running?
Curious Tony