Bandit250. Very noisy engine.

I did fuel level adjustment for this carburetor. Though the engine became in good condition.
But a sound is loud rattle-rattle.Exhaust gas is stinking.

I hated dismantling this engine very. Because it is troublesome.
However, I took off a head cover to check it. I needed some determination for it.

I checked it. Suspicious partial ... cam chain, valve clearance ... problem were not found.
I expected these. A chain lengthens too much. A valve locks it by carbon.

The head inside is very clean. There is not an oil gossan. I was surprised a little.

The possibility moved to a cylinder and a piston.
It is what I was afraid of most.
I must remove a cylinder block.