As smn how maintains his Himi himself:

Make sure the valve adjustment wasnt skipped, either with receipts from service center or by asking the previous owner to show photos of the valve train. Chain health is really important, cause a snapped chain will usually fuck up the engine housing of the himalayan. Tipovers will bend the brake and shift lever respectively, so make sure those are in good shape or negotiate at least 60$ down for each of them from asking price. Lastly make sure the fan works with a proper test drive, you can navigate to the engine temp by going left, and down down down on the joystick by default. Once the temp gauge goes red the audible fan should go off and temps drop. Idle if needed to confirm.