The upper hose on the OE setup cannot be separated from the 'T' and the lower two hoses; it's one complete unit.

Your best options are:

1) HEL (as mentioned). Their standard "race" setup for the Ten, which has two separate lines running one to each caliper from the master cylinder, actually has plenty of slack to deal with moderate risers and handguards. The separate lines (without the rigid link) also give you a bit more flexibility in routing too.

http://www.helperformance.com/hel-brake-lines-for-yamaha-xt660-z-tenere-2008-2010.html

2) Venhill. They make custom length hoses, but will work out more pricey than the above.

http://www.venhill.co.uk/

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