Alert the semi-solid fork is probably not the right terminology, it shows that I don't know 100% whether the work has some sort of inner suspension.
My bike is almost this one but I feel there is some sort of inner suspension thing because there is a rubber or it is just decorative and I just imagine it is suspension due to tires. There is a small rubber cork to the fork so I think it is to oil the suspension. I looked inside the rubber thing and there is suspension looking metallic thing. Notice the small rubber cork for the oil, I have never put anything there.
I haven't yet dissasembled the bike and no specific specs because I bought it as 10k-driven used bike. So no precise diagnosis yet.
Description of the sound
The front makes a lot of whiizing sound. When I drive with weight on the front, the sound disappears. When I slow down even a little (i.e. the force is less on the front due to de-accelerating), the sound emerges again. Because of this observation, I thought that the fork is not rigid-fork but with small suspension. What would you suggest to do with the fork? I will disassembly it and apply some sort of special lubrication (it may be just that lubrication is eroded) or will I do something else?