A new LS2 CR1 helmet found under Decor / Misc. Decor, costs 50. It's specially made to fit onto The workshop 2. Shelves . You need Ambitions or a later pack for the helmet to show in your game. Use cheat moveobjects on to place helmet on the 2nd shelf.
LS2 CR1 helmet (MediaFire)
The workshop 2. Shelf set
The workshop 5. Bell MV2 helmet
The workshop 4. Bike on hydrolic platform and rear wheel stand
The workshop 3. 6 tire sets
The workshop 1. Bench, vise and hammer