I was told when preparing the bike for the Isle of Grits that in the cool weather it would be a good idea to tape part of the radiator over. I hate removing Duck Tape from areas it has been hot so decided to see if I could make something that would cover part of the radiator and be adjustable while riding. 

It took most of a week to get it right due to clearances, and difficulty designing and making a system that would allow me to adjust it while riding. The flap is 1/32nd aluminum that has a shape to clear forks etc. This took many experiments to get right. The flap is mounted to an aluminum hinge which is all then held in place by the bolt in the center top of the radiator. 

I made and mounted an arm on the side of the flap and ran a 1/4 inch aluminum rod to that and up past the inside of the fake right ram air tube. After making four brackets to secure the tube and allow adjustment finally got it right and bolted it to the inside of the ram air tube. The mounting position of this little bracket is critical. Then I cut sections of surgical tubing and installed on the tube. This allows the securing bracket to hold the flap in place between the two fingers of the securing bracket with the door in any position. Then made an arm and using epoxy to hold a bolt and installed it to the top of the tube to allow easy grasp with gloves. 

I have a faster warm up, control of temperature up to the thermostat setting and don't need duck tape. I have found that the radiator is so big for this engine I can almost always just leave the flap closed unless I'm pushing the bike really hard.