Many Racers Take Them Off to Save Weight:
Don't Remove Your Heat Shields....
Or You'll Lose 10 Horsepower !!

THE R6 HEAT SHIELD  Think of it as 10 Free Horsepower ! Most bikes have something like this behind the radiator. The purpose is to keep the heat away from the fuel system.

 Those black plastic / rubber pieces keep excess heat from getting to the carburetors / fuel injectors. The Yamaha R6 uses 2 different ones. The one pictured above covers the triangular space between the steering head and the frame spars to block out radiator heat. The 2^nd one is the rubber blanket that goes between the carbs and the engine to shield rising engine heat.    

If you want your bike to be fast:
Don't Remove Them !!!

What are they for ?? Well, imagine sitting on a starting grid (or at a stoplight). What would happen if you put on the choke ? Bad idea right ?? …the engine will load up with fuel and run bad. The same thing happens when the heat shields are missing. As you wait on the grid, the float bowls heat up, the fuel vaporizes, and your fuel / air ratio becomes too rich. When its time to go, the bike will be noticeably slower. 

Once you get moving it only gets worse, because now hot air from the radiator is BLASTING directly at your carburetor’s float bowls! Finding the correct jetting is impossible, since even if you set up the carburetors perfectly on a dyno, the fuel air ratio will always be controlled by how much extra heat the carbs get.

Think of it as Reverse Ram Air
…the faster you go, the less power you’ll have.

Heat Shields are Cool !!