Hi when open there are clips on opposite sides when unclasp should bulb and innards come straight out leaving glass and bowl.Never done one so don't want to damage and putting back together same way I suppose.Been looking for other people who done this and other electric work on Bultacos as better to watch and learn before attempting.

Hi, 

To access the bulb, simply twist the serrated plastic collar anti clockwise and pull it out the back of the reflector. (NO TOCAR) do not touch the silver of the reflector. 

If you remove the spring clips, the lens and reflector can be separated from the chrome plated rim.

Hope this helps

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