use of restrictor plates, need opinions, thoughts?

[hanz63]

Really I'd think if these engines would run that much air fuel mix that even those gaskets allowed, they wouldn't be here long. But then again, I'm no engineer.

[KE4AVB]

Engine OEMs are just restricting the peak HP based on the equipment design specs. It is a way to sell supposedly larger engines to the equipment owners. The restrictor plates are mainly the difference between some engine models. I have one commercial customer that has notice a slight increase in HP of his Z950R that I removed the restrictor plate from his Kawasaki engine. With these many of the engines are physically using the same parts like the FX7510, FX801, and FX850 which are basically the same 852cc engine.

Since these are governed engines they just produce a little more HP under heavy loads. Once governed rpms are reach the system start reducing the air flow through the carburetor ie via variable restrictor plates. You will have seen these variable restrictor plates on all carburetor engines. You probably know better as throttle plates (butterflies). I also seen a few carburetor where the throttle plate opening where limited for the same HP restriction. Remove the limiter and no notice engine speed just a little stronger under load. But that doesn't the peak torque either as is usually somewhere in the mid rpm range anyway. Now if the governor is crippled then you could push engine beyond it design max rpm limits and then things would start coming apart.