Had the same problem with Moby Brick when I decided to do the domino thing in the garage last year. Fortunately it was only on one side on my bike so I only had half the work.
First, is the windshield unbroken at the tabs that mount it to the "horns" on the fairing? That is critical to getting the parts aligned for the first part of the repair. You might have to break down and get an undamaged one.
Second, install the windshield, getting all the screws installed in the broken pieces. This will get things aligned so the windshield will go in after the repairs.
Third, using a straight edge, reflections of fluorescent light tubes, eyeball, etc, get all the parts in exactly the place where they should be. Don't rush, this is the most critical part of the job. If there is a bit of spring in them, you might need to hold them in position for the next step. Try not to be in that situation though, as you will then require a helper.
Fourth, with the parts perfectly aligned, saturate the fibers of the damaged area with CA(super glue) and then give it a shot of catalyst spray. This stuff can be had at any hobby shop that cater to the guys who build R/C airplanes. This will immobilize the broken parts in position so you can do the rest of the repair.
Do one break at a time, making sure that you have the parts perfectly aligned. Did I mention you should have the parts perfectly aligned? Once they're glued, it gets VERY hard to adjust them. With the windshield attached during this part of the job you can be sure that if all else fails, at least you will be able to attach it again when everything is done. The material the fairing is made of is very conducive to this repair technique.
A trick that the model guys use that may help to get stronger glue joints is to dust a little baking soda into the damaged area as a filler, working it in with a cheap natural bristle chip brush before you apply the super glue.
At this point don't be worried about glass fibers sticking up all over the place. You are going to grind them all down for the next stage of the repair.
When all the breaks are glued up look at your alignment. Are the surfaces straight and in alignment everywhere they should be? Make sure everything is perfect. This will be your last chance to get it right.
If there are any repairs that aren't perfect, you have a chance to get them there by soaking the joint with acetone applied with a small paint brush. Paint it on a little at a time keeping the area wet without the acetone getting all over the rest of the fairing. After a few minutes, the super glue will have softened enough to allow you to GENTLY bend things into alignment. You will have to hold them there until the acetone evaporates or at least keep going back every couple of seconds to straighten things up. When the acetone finally evaporates(about 20 minutes) give the joint a second shot of super glue and catalyst.
At this point all the broken pieces should be in perfect alignment and ready for the fiberglass. The fiberglass is necessary to restore the full strength of the fairing, and to prevent cracks forming at the breaks after all the work is done. I like to use a very light 3/4 oz. cloth tape about 4" wide for my repairs. The tape with it's bound edges is very easy to work with. I get it at the airplane hobby shop where I get the Super Glue and catalyst.
Two layers go on the top and at least three on the back side of the repair(use more if you can back there, you can't make it too strong).
First step in this phase is to get a sanding disc for a power drill. The old school drills with cords are the best. 80 grit is about right. Gently grind away the front surface with the disc to a depth of about 1/16". Do the full width of the "horn" at least 5 inches long on the horn. This is to allow you to stagger the 4" wide tape so that both edges of the tape are not on top of each other at the edges of the repair. Make sure the area you are grinding is smooth with no dips, high spots, or ridges. Any major dips in the surface will result in a weaker spot from too much resin for the glass.
When the grinding is done vacuum up all the dust. Cut two pieces of glass tape and check where they will be going on the repair. Trim them to fit, and mix up a small amount of polyester resin per my instructions in the other thread. Paint it on with a chip brush and lay on the two pieces of glass tape one at a time working the air out of each. You have about a minute to get each piece down. Don't try to get the glass to bend over sharp corners. It won't do it. Just get it nice and flat on the repair area.
As soon as you have the glass in place clean the brush with some acetone and wait for the resin to cure. If you mixed it right, that shouldn't take more than 10 minutes.
Repeat for each of the broken areas, working from the bottom of each horn to the tip. Be GENTLE with the sanding disc. The parts can still be knocked out of alignment. When all the breaks have been covered on the outside, go to the back and remove the windshield and glass the back side. This will be a bit easier in that you only need to rough up the surface with the 80 grit to make the resin bond better.
Again, do one break at a time, cut your fiberglass to fit and let the resin cure before moving on to the next break. I am going to recommend that you only use three layers on the back side, because the resin might cure before you can get all the air out of more layers.
I would also recommend that after each repair on the back side you make sure you can get the windshield back on with all the screws.
Once the glass work is done it's time to do the bondo and surface prep for the paint.
