Words to the wise: In going after a valve adjustment on my 2003 R1150R I was removing the OEM valve cover protectors/head guards on my bike. These are the black plastic version with 3 attachment points,one on front and back of kug, the other under the jug. The one under is the culprit in my case and on each side! I encountered resistance there & eventually after trying a soak of the threads I proceeded to break of both of these socket head screws. The guard uses the bolt on each side that is in a threaded hole that is open at the back. My guess is that this allows corrosion to be more likely with these two holes. What makes for a difficult removal is the fact that these holes are both too close to the jug to allow a straight shot into the broken bolt for drilling. Not to get into a "broken bolt tutorial" here but I was able to use a 1/8" drill and keeping the drill very close to the underneath side of the jug, drill through the remaining bolt. When possible I avoid using bolt extractors but had a new Craftsman available and I tapped it into what looked like a doable situation. FWIW, the pkg said made in China. It broke before I could even give it much pressure. The other side I have almost out via more conventional chipping away with hardened steel "needles" I have in my tool box from past industrial work. Seems to be a job for a carbide burr next or maybe even a diamond burr using my Foredom tool handpiece. Heat is a hard sell for me in the jug location w/o removing the finish from adjoining parts.
Beware of these two bolts that are encountered in a common maintenance procedure! It's not an easy spot to work nor a kind to your bike operation.
I'm considering using a through bolt in a clearance size hole next rather than a cleanup the threads operation.
I've seen these black guards criticized before, as compared to the more robust tubing style but find they actually do the job well with little weight, never had an issue before but been some miles since valve adjustment too. Hope I created some caution here.