Recently had a faulty grip on a F800. Same would apply to the 1200.
For those that are interested, here's how to do it.
This is what I started with:
Step 1: Remove the grip. Not going to give the rundown on how that gets done. It's pretty straight forward. The photos in this how to are mixed between the two grips but the principles are the same.
Once it's off, you will have this. Notice the bulge in the grip where the rubber has stretched. That's going to be handy.
Step 2: Cut the end down to the hard plastic core, about 5mm from the end of the grip. Cut all the way around.
Step 3: Do likewise with the other end.
Step 4: Insert a sharp knife at an angle into the bulge. DO NOT cut straight down.
What you see here is the element below the rubber. That's the part you don't want to cut into.
Step 5: Carefully slice through the rubber peeling the grip away as you go along.
When you're done, this is what you'll have.
Step 6: Now trim off the two ends.
And the other side.
I cleaned up the ends on the bench grinder, VERY CAREFULLY, until I had this.
If at this point you only want to replace the grips, skip directly to step 13.
Step 7: Now, have a look at where the wiring attaches to the element. If they are still intact, find a magnifying glass.
Follow the tracks and find the break. It's almost like the puzzles you did as a kid to find the path through a maze to the other end. Somewhere there will be a break. I found it here.
Step 8: Using a small Dremel bit, carefully grind through the plastic/mylar/whatever covering to expose the copper track on either side of the break.
Step 9: Using a soldering iron, carefully tin the 2 exposed ends.
Step 10: Using a single strand of thin copper wire, bridge the gap at the break.
Step 11: Test with a multimeter on the Ohm setting. What used to be an open circuit is now 9.1ohm.
Retest with the GS911: Beautifull words those: "The fault is not present now!"
Step 12: Cover the soldered area with a LITTLE Pratleys Plastic Steel just to protect it and smooth it over.
Now we get to fitting the new grips. Generic grips are normally different sizes, a larger one for the accelerator side and smaller one for the clutch side. The smaller grip is designed to slide directly onto the handlebar and not over the heater element. This unfortunately necessitates buying 2 sets of grips as you are only going to use the larger grip of each set. I would recommend a decent quality grip. Even at R180/set, it still beats the OEM R1800 hands down. In the photo below, we are only going to use the left grip.
Step 13: If the end of the grip is closed, punch a small hole in it. This will be used to fit the grip easily. Do not cut the end of the grip out at this point.
Step 14: Place the repaired element back on the bars and push the grip on a little way. 10mm is enough. Now insert an airgun in the small hole and apply a little preasure.
Step 15: Pull the trigger while maintaining the pressure. In one smooth move the grip is on.
Step 16: Now carefully cut out the end of the grip.
Step 17: and pop the end onto the element tube.
Step 18: Re-assemble the bar end weight and hand guard and you're ready to ride again, with warm hands!
Step 19: Plug in the GS911. End result: