The engine revs fine to 4.5K then i can hear a strange but not loud sound from the engine.
I can hardly get it to rev more than 5K.
It sound like a leaking sound Fuzzz.
I have changed a lot of things which have helped me on other problems.(OVP,COIL)
I also do regular service air filter,plugs and the others.
The fuel filter is not changed.
The lambda works fine.
My first thought was some kind of fuel delivery problem.
But i have kind of ruled that out because my engine starts perfectly in cold wheather.
Could it be the valve guides or the timing chain.
Have anybody had this type of problem ?

Pelle 300E 4M -89