got a bike with no v5 owner lost it,no number plate,ive got engine and frame no been on dvla webb site but getting confused,the bike is 1984 dt 80 mx which i am doing up.

if you've got the engine and frame numbers im pretty sure the DVLA will give you an age-related plate

You can phone DVLA direct and they will inform you exactly what you need, however in my experience,

You will need a dating letter from Yamaha UK. If you present that, plus clear photos of the engine and frame number at your nearest DVLA centre they will take the deatails and may ask you to present the bike at a VOSA centre where their guys will look at the numbers. In my experience the VOSA guys are good at picking up any unauthorised alterations of the numbers. It will be good (for you in the event the bike was stolen) if you have a receipt from the guy you bought it from.