Kawasaki Ninja 400 Heat Shield/Thermal Deflector 2018/current


The Heat Shield/thermal deflector, it’s designed to protect the air box/ filter area from the thermal radiations generated by the cooling radiator and combustion engine.

Race Use Only


Spears Racing has been working on this newest product called a Heat Shield/Thermal Deflector for the Kawasaki Ninja 400cc , this unit will allow your motorcycle to maintain a lower consistent air intake temperature to your engine which will make your bike run soother and generate more power. The Heat shield/Thermal Defector is made from 6061 aluminum, lasered to perfection and allows you the ability to have it set to were you want it to be height (note the Slotted Bolt Holes) and is finished off with a  black satin finish.

Because of the forward-positioned air intake uses two (2) small ducts at the front of the bike to route fresh air to the engine, the air is heated by the engine and will pull down performance of your engine. Cold air is dense compared to hot air, which allows for a better quality burn when it is mixed with fuel and ignited. The Heat Shield/Thermal deflector, it’s designed to protect the air box/ filter area from the thermal radiations generated by the cooling radiator and combustion engine. The Heat Shield/Thermal Deflector has the degree of a separating wall/deflector between air filter area and rest of engine compartment.

The use of the Spears Racing Heat Shield/Thermal deflector has the following advantages: the air flow generated by cooling radiator (i.e. thermal radiations) is deflected outside the air filter area the temperature of the air box/air filter is maintained at an optimum level (i.e. their over-heating is avoided).

Several dyno runs were performed thru out the testing process, we have found that installing the heat shield there was a large reduction in air temperature inside the air box and also the surrounding area ;ie above the heat shield to the air box, this number was approx. 30° cooler.

Temperature variation measurements have been carried out at different speeds both in the area of the air filter and outside the area of the air filter with the Spears Racing Heat Shield/Thermal deflector protection
Because of the position in the engine area(enclosed in a tight area of body work) the intake is highly expose to thermal radiations from the heat generated by the  cooling radiator, exhaust pipe and engine itself which is a big disadvantage, the intake air it heated and the result is lower density, thus containing less oxygen per volume unit than cooler/cold air.

The dyno run intake temperature was .06 off of each other and both were above 94°

Kit contain the following:

2ea 6mm spring clips

2ea 6mm bolts


*** The Install of this unit will require the removal of the OEM Radiator Fan Assembly***

Spears Racing has been designing and making race products for decades, their continuous committed to excellence to advance as the industry changes. This commitment has resulted in more components specific to certain applications, proprietary products only manufactured for us. Each of these aspects has been put through stringent research and development stages to ensure that our product will exceed your standards.

Race Use Only