Hello from Greece

Hello everybody i am from Greece and my name is Dimitris,iwant to ask you something,i want to bye a xr 650 r used, and i want you to tell me what thinks must see on the bike so i can bye it,thank you

The XR650 seems very reliable.
I have read that early bikes had a problem with a clutch bush other than that if the bike looks tidy and well cared for it should be OK.
Take a look at the wheel rims, if it has been used hard off road these will show scarring.
The spokes in the rear wheel are also prone to becoming loose and breaking.

I used to have a Husaberg fe 501 e 2000 and has been stolen and i want to bye xr 650r for enduro use,is this ok?

The XR is a heavy bike.
I have found that it can ride any trail but it is hard work.
If you are young and strong you could have fun riding the XR in competition enduros but you will not as competitive as you would be on a lighter bike.
Hopefully this will explain it
I do not compete but trail ride on a 250 two stroke and the XR, I can cover the tight knarly trails much faster on the lighter two stroke but still really enjoy riding the XR.

I am 105 kg and 183mheight and my job is to lift weights, the Husaberg feels to me like a 125 2stroke so i beleive the xr will be very good for me.

Look for one with a stock engine.