From the Japanese manufacturer TAKEGAWA, specialist in high level preparations for the Honda CRF engines and their Chinese replicas, YX and Z 150 / 160cc, we get the springs racing. These springs are harder. Especially calculated so that the motors that seek the maximum of power do not meet with the take off of the valves on the camshaft.
It means that with the series spring, we will remain at high rpm with which the valve loses contact with the cam. This fact causes that they do not close correctly. It is simply observed that it reaches a point that it can not rise more than rpm due to leaks. But it can cause impacts between the valves and the piston, which would be the breakage of multiple chain components. In these details it is worth spending a tad more and have the guarantee of Japanese or European quality product that risk a general break of stock and piston.
With these springs we will see that the engine will not limit us the rpm and we will be able to achieve the maximum power of the engine. It is one of the first things to play on a Pitbike engine along with the carburetor. Reinforced springs