After not running the Commando for three weeks I found the oil level was about a pint low. This is not uncommon after a few weeks laid up so I decided to drain the sump. However oil continued to drain from the sump and on investigation I realised it must of been draining from the oil tank and did not stop until I replaced the plug. Is this a definite indication that the oil pump needs an overhaul or may it be due to another problem. Thanks in advance