Good used 14mm rear brake master cylinder with reservoir to suit the models listed below.

• K40 (K 1200 S, K 1300 S)   (04/2003 — 09/2015)
• K43 (K 1200 R, Sport, K 1300 R)   (03/2004 — 07/2015)
• K44 (K 1200 GT, K 1300 GT)   (11/2004 — 10/2010)

My suit other models but check the OEM number first with your one.

Came off a 2008 test ridden K1200GT.