I had starter problems recently which were caused by a broken Woodruff Key, but managed to find one with an exact fit:
This is the engine based on the Suzuki DR200
The correct Woodruff key for this model (which does NOT require grinding or filing), is this one from Suzuki UK:
Genuine Suzuki GT25EX (X7 1978-1981 Crankshaft Key 09420-04008-000
This can be found by doing a search on ebay.
http://www.ebay.co.uk/itm/Genuine-Su...item3391de4e67