K100 starter carbon brushes replacement

Stripped the starter motor and noticed one of the carbon brushes on the negative post needs replaced.
Anyone here replaced the brushes using generic carbon brushes and soldered them in place.
I know you can buy each individual brush from Motorworks etc, but just wondered whether anyone here has done a suitable DIY with standard 6x9x13 mm carbon brushes.

Not yet, would like to know how you get on, I've got the starter out of my K75c sat in the garage at the moment. Fitted a spare unit to the bike for now, was going to order bushes from Motorworks and refurbish the original.
Good luck and hope it works out ok.

Ended up utilising a new carbon brush from an unused washing machine set that I had in my electrical toolbox.
Filed the brush down to size and resoldered. Works a treat. Starts up easily now. About 1 hour work.