So far Ive calculated the prices of parts.
Prox piston set ~150€
Athena gasket set with valve stems 140-180€
Crankshaft bearing RH ~30-40€

Crank pin+bearing+rod+chain guides+chain with shipping is 301€. Those are from https://www.motorcyclespareparts.eu but I will ask my local Yam dealer and should get answer tomorrow. Also got one shop that might get even cheaper than Yam dealer. Then I will see where I buy which part, so I get them as cheap as possible from different dealers. Right now the price for parts is around 670€.

Work price:
120€ with engine on the desk. I will take off the engine(No problem for me to do that or other jobs on my bike or car, but I will not touch the engines, cause if I do something wrong there, its way too expensive for me to fix again compared to anything else and the error margins for engine are lot higher cause too many parts).
40-50€ for crankshaft pressing. Should be done in a day.

I removed my old XT600 engine total of 3-4 times. I can't run the engine anymore cause the case is off already. But most shops agreed that its the rod. But to find it out if its true, I need to remove cylinder anyway. Its much easier for me to transport the engine than whole bike.

While the engine is off, then I can grease rear link if needed. Do cush drive mod. Clean up everything properly. Do the tail mud guard with rubber under the seat(aftermarket exhaust problem) so it wont push dirt there(used silicone for the moment).