[5valve]

What you have is OK.

What I have is non solvable and is calling probably for new cylinder/piston set.

What you see in pics has happened 4 times in a row over a span of 7 riding hrs. New piston and diamond hone every time. Bottom end currently doing 2nd time, conrod included.
Piston to cyl clearance 0.08mm.

Piston in pic has done 3hrs.

The actual cylinder lines in picture were created in newly honed cylinder in 5 minutes of idling only. No dirt, everything clean, completely stock jetting, to exclude any lean condition. Black plug.

Total engine hrs 72. I have never came upon such a problematic bike. Managed to accumulate 7 riding hrs since february and constant repairing in between.

Bike kind of works normally, but at constant gassing or in tech terrain, heat arises, engine vent constantly on, due to heated water. Sth is griding. Thermostat removed, waterpump ALU impeler, cases and cooling system pressure tested OK.
No pinging, no heat pitting on squish band or piston faces.

Have no clue what is going on....