Method and an arrangement within a motor saw, having a guide bar, a drive motor unit including with its chassis a drive motor, whose rotatable shaft supports a drive disc, around which a portion of an endless saw chain runs, the saw chain also being adapted with its remaining portions to run along and form the guide bar arrangement with its guide bar and along tracks allotted to side edges directed away from each other. An anchored support plate, a displaceable clamping plate and with an interrelated arrangement in an inactivated position, the end area of the guide bar within a first mode displaces the end area in a direction perpendicular from the plane and from the support plate, and within a second mode displacing the end area and its guide bar in a direction along the plane allotted to the guide bar and out of the inactivated interrelated arrangement.
