BMW R850R: Windshield

The below repairs, replacements, and what-not have all been done by me on my 1997 R850R. Many of the procedures can apply to other BMW bikes of similar vintage, primarily the R1100R and to a certain extent the R1100GS. Do not attempt any of these procedures unless you're confident in your skills - however limited - as a shade-tree mechanic. Don't send me hate mail if you mess something up!!

Cutting down the windshield

Tools Needed: low-tack (painter's) tape, 2 inches or so wide; tape measure (preferably cloth); medium crosshead screwdriver; small flathead screwdriver; small pair of pliers or wrench; Dremel (or similar) high-speed rotary tool with cutting and sanding wheel attachments

Parts Needed: if you replace the stock "bolts" like I did, you will need 4 #8x32 cap bolts (1 or 1.5 inch length), 4 #8 washers, and 4 #8 nuts with nylon inserts (lock nuts) - if you do this you'll also need the appropriate hex wrench to drive the cap bolts - I think they are 2mm hex.

Note: There will be flying bits of plexiglass in this operation - the use of eye protection is HIGHLY recommended.

Before:
 

During:
I wanted a shorter windshield on the aftermarket Parabellum "Scout" fairing simply because at my height (about 6 feet 2 inches) and the way I sit on the bike, the windshield put on by the previous owner (who is shorter than me by about 2 inches) put the air flow directly at my eye/nose level. I couldn't ride with my face shield up at low speeds because of the direct blast of air, and at higher speeds I was forced to close my face shield completely to prevent the buzzing noise of a wildly vibrating face shield. He did send me home with two additional windshields - both taller than the installed one!

Since I really liked the look of my former '99 Suzuki Bandit 1200 - which had a very café racer look about it - and I've always loved the look of the mid-70s R90/6, I decided a short, sweet windshield would do the trick.
 
The big decision was - exactly HOW short? The end result is a bit shorter than I intended, but it looks kind of cool and put the wind on my chest, right where I wanted it.

1. Put the bike on its center stand and figure out a way to basically center the fairing in relation to the rest of the bike.
2. Estimating roughly how high you want the windshield to be, use the low-tack tape to cover a swath of the windshield wide enough to handle the approximate curve you want the finished shield to have. Using this tape will not mar your windshield and will protect the plexiglas from burning when you cut it with the Dremel.
3. Using the tape measure, find the center line of the windshield and mark it with a grease pencil or similar removeable writing device. You can also mark other waypoints on the windshield, such as where the mounting points are and where the ends of the fairing meet the shield.
4. Pry off the plastic caps covering the mounting screws - use a knife or small flathead screwdriver.
5. Using the crosshead screwdriver on the outside and the pliers or appropriately sized wrench on the inside of the fairing, remove the plastic mounting screws. If, like me, you think this is a cheap and easily breakable way to mount your windshield, discard these fasteners - but be sure to retain the larger clear deep washer that the caps click onto.
6. Referencing your center point mark, lightly sketch out your desired windshield curve, erasing and re-sketching until you're happy with it. I used a piece of string to hold the line I chose, holding the string tight with one hand behind the shield while I drew over it on the front side with a marker.

Note: You'll need a hard, narrow, but flat surface to best cut the windshield - I used the neck end of a hard guitar case to rest the shield on as I cut it.

7. Insert and secure the cutting wheel into your Dremel.
8. The cutting wheel is going to work more efficiently in one direction than the other - pay attention to whether or not you are guiding or pushing the tool - since you want the tool to do the work, you want to be guiding it; if you are not, position yourself and/or the windshield so this is what happens. Go slow, let the tool do the work, and follow your line as closely as possible.
10. Once the shield is cut in two, discard the unwanted portion. Remove the tape from the remaining portion of the windshield.
11. Remove the cutting wheel and insert a sanding wheel into the Dremel.
12. You want to smooth out the freshly cut portion of the windshield and slightly bevel or round off both the front and rear corners. Again, go slowly and let the tool do the work. If your sanding wheel becomes worn, switch it out for a fresh one.
13. Reinstall the windshield using your shiny new stainless steel cap bolts and locking nuts (which I purchased at Home Depot for a grand total of $2.37). The nuts should be firmly tight, but not overly so - you don't want to crack the fiberglass of the fairing.
14. Replace the plastic caps that cover the mounting bolts (now they're bolts, anyway).
15. Brush all the plexiglass debris off your clothes while you're still outside, and toss that stuff right into the laundry. Once you're all cleaned up, take your bike for a test ride!
16. If you notice any instability in the windshield while riding STOP IMMEDIATELY and retrace your reinstallation steps to make sure you didn't miss anything.
17. Enjoy your cool looking new shorty windshield!

After: