My motorcycle windshield was broken right after I bought the bike (used). I was initialy planning to replace the plastic and reuse the existing hardware, but I really did not like the large size of the old windshield, and the mounting was really ugly. New motorcycle windshields are available in a variety of sizes and shapes, but they are expensive, and I just could not find exactly what I wanted.
Molding acrylic plastic is not hard to do (I have made a couple of items this way before, but not a windshield), and the material is readily available, so I decided to try making one. This one has a slight compound curve (bend in two diections) but most windshields are just a simple curve.
The bike in the picture is a 2001 Honda Magna 750, with my homemade windshield installed. This type of windshield would probably work for most any bike. It is fairly small, and I did not see any need for metal bracing on the windshield. It is mounted with four struts of 1/4" all-thread, bolted through the plastic. It has held steady at up to 75 MPH (legal, here in Texas), with no vibration or movement. It has killed allot of bugs that would otherwise have been splatttered all over me!
Step 1: Materials & Tools
For the plastic part of the windshield I used clear acrylic, .22" thick. A 18" x 24" piece was large enough and cost less than $20. It is sold in home improvement stores for replacing glass in windows.
These are the materials that I used for the mounting hardware. This will vary from bike to bike, depending on what is available to attach it to. I attached to the forks only, but a taller windshield might be braced to the handlebars.
4 Electrical Conduit Clamps - plated (Select size to fit on the forks and/or handlebars)
2 feet 1/4"-20 All-thread Rod - plated (struts)
4 1/4"-20 Acorn Nuts - stainless steel or chrome plated
8 1/4" washers - stainless steel
12 1/4"-20 Nuts - stainless steel
4 Rubber Grommets - 1/4" ID, for 1/4" thick material.
2 feet 3/8" dia. Black Shrink Tubing (to cover the all-thread rod)
1 Inner Tube (to cut into pads to isolate the clamps from your chrome)
1 yard Felt Cloth - synthetic or wool
Consumables which you will need:
Sandpaper: Various grits from 200 to 800 or 1000, depending on how shiny you want the edges.
Cardboard. The exact size and type will depend on the shape and size of your windshield.
Razor blades, Dremel cut-off disks, saw blades, etc.
Contact or rubber cement. This is to glue the rubber to the clamps
Full size baking oven. I used the one in my kitchen. We are only going to soften the plastic, and you should not be ble to even smell the plastic when it is heated. Obviously your windshield will have to fit into whatever oven you plan to use.
Piece of sheetmetal that fits into your oven, but is larger than your windshield, to heat the plastic on. This should be clean and smooth, no paint, preferably galvanized.
A sabre (reciprocating) saw, jig saw, or coping saw, to cut the plastic. I used a cheap hand-held jig saw with a fresh metal-cutting blade and it worked well.
Drill; manual or electric. A stepped drill is very good for drilling plastic. If not available you will need at least a 1/8", a 1/4", a 3/8", a 1/2" and a 9/16". See the section on drilling the holes in the windshield for details.
Files, course and fine.
Wrenches to fit nuts.
Vice: for bending the struts.