F800GS rear brake problem

Hi All,

Firstly I'm new to the forum so hello. I live in London, work in the City and ride my F800GS in every day!

I have had the bike since new(~6 months) and to begin with the rear brake was great, very responsive with little travel and would bite instantly. However recently it has taken a lot more travel for it to engage and and feels a lot less responsive.

I took it to my local dealership and they bled the system and replaced the master cylinder as apparently the piston was sticking. I do now have a back brake again, however it is not as tight and instant as it was previously and still requires a lot of travel.

They said there was nothing more they could do and that it 'wasn't any different to any other F800's they had in'.

Can anyone suggest what I might do to get it back to how it was before? On a motocross bike you would adjust the piston up that is attached to the lever itself to reduce travel, does the bike have this option?

Thank you for your help

Check that the caliper is sliding freely on the pins. Push the caliper in towards the disc. If all is well the caliper will slide on the pins and the piston will be pushed back in. Make sure you pump the piston back out again. Any further work required to free it off will mean the wheel will have to come out.

If you want an independent engineer to check it I can highly recommend Jap & German Motorcycles in Druid Street (www.japandgerman.co.uk).
As you are in the City they wont be too far from you, being just south of Tower Bridge. They can check for any problems and make any adjustments you may want. Plus there is a Really, Really good coffee shop just round the corner.
And welcome to the forum.

Welcome to all things UKGSer

People adjust the position of the rear brake pedal with the adjustment from the pedal up to the master cylinder (it pushes on the piston to operate the brake) this is a big No No

There must be play so that there is no pressure on the piston and it can fully return to its 'at rest' position. By all means adjust the rod to give the minimum clearance ... thus reducing the length of the brake lever movement before it starts to push the piston