How do i replace the starter motor on my r1200gs 2004 bmw

remove the cover ,wind motor over to Top Dead Centre ,look for timing marks (may need to turn over once more to get all the marks to line up) Mark all the reference marks with a white paint pen to make them clear , Release the tenenser & lock it out remove the old belt ,refit the belt making sure the marks all line up release the tenenser and lock it ,recheck your marks ,wind over by hand a couple of times to check everything is OK refit covers

There is no cam belt. Cams are chain driven and you have to remove and strip the entire motor to change the chains.

Will depend on year, later models use a CanBus system, which replaced the fuse box, hence no fuses. If something trips the canBus acts like a fuse to protect what ever caused it to trip, turning off the ignition for 30 secs and back on again resets the system.

There is no fuse box. All electronic fuses which are controlled by the CanBus.

No, Diagnostic software cannot measure your clutch wear.

Remove the starter motor. You will be able to see a small section of the clutch and measure the thickness.

You basically split the bike in half. You need a way to support the machine under the engine and then remove the whole rear section of the bike. You will have to disconnect the brake lines to the rear brakes and remove the wiring harness to the rear section of the bike. It is not a job for the timid..... but can be done if you have some mechanical aptitude and take your time.

Much easier on the R1200GS than the R1200CL listed in your title