Displaying a paper tax disc on your motorcycle is no longer necessary from today onwards (October 1st 2014), though you will still need to tax your vehicle. If you buy from a dealer, then they can tax it for you, if not, you will have to do it yourself by internet, phone or the Post Office. There is no grace period, and this must be done before you ride any bike away. When you sell a bike, the DVLA will automatically refund anything left on your tax disc to you, but it will only refund to the registered keeper and in whole months, which does not include the surcharge for buying 6 months tax or via Direct Debit, which is 5%. Details here. Dealers are advised to use Trade Plates for vehicles in their stock in all circumstances including test rides by staff or potential purchasers. This is to avoid the problem of not being able to identify whether the bike is correctly taxed by the current owner. The online service may still show the bike as taxed if it has not yet been transferred to a new owner. You can check on your VED status online here.