Cutting a Motorcycle Windshield

As Margaret has gotten more comfortable on her bike she has had an ever growing issue with the windshield.  She's getting a lot of reflections and glare on the inside that is affecting her ability to see the road due to its height. Everyone has their preferences on how tall, short, fat, etc. a windshield should be. Most articles, riders, and accessory places will recommend that your eye site should be just above the top of the wind shield.  I tend to agree with this.  Try having a windshield that you have to look through and ride in the rain.  No wipers means you can’t see through it and you’ll end up having to crane your neck to the side of the windshield to see the road.

We finally decided something had to be done for her.  We could take it somewhere and have a company cut it for us or try it ourselves.  HA! Let's do this! No Fear!  We Ain't Skeerd! The worst situation that could come from this is we could mess it up and have to buy a new windshield.  It’s not like we would mess up the bike from improper procedures on this task.

We started by having her sit on the bike in riding position. As corny as this sounds I took a builders level and stuck it close to her eye until the bubble showed level and marked that spot on the windshield.  Naturally she whined that I stuck it in her eye, blah blah whatever dear. This gave us a good visual reference as to where her eyesight came into contact on the windshield.  Then we measured down 1” from that spot for our cut point.  This point was exactly 2.5” from the top of the windshield.  I measured 2.5” from the top center around towards both sides and made a lot of pinpoint marks as I went.  When you get to a certain point towards each side you have to begin to taper your measurement to merge your cut line with the side of the windshield.  This way it won’t look like you just chopped off the top.

Next I connected all the dots I made using a permanent marker.  I did this freehand but had made enough dots to where it came out nicely rounded.  Now I took painters tape and ran it on the lower portion of the windshield along the marker line.  This helps prevent chipping if the jigsaw blade catches too much.  I made sure to put a couple inches of tape to prevent the jigsaw base from scratching the plastic while moving it along while cutting.

For the cut I purchased a Bosch Plexiglass blade pack at Home Depot for $8.95.  This was our only expense on the project since I had everything else necessary.

I started at the blend point on one side of the windshield so I could make one continuous cut most of the way around without having to stop and reposition the blade.  I didn't push very hard or force the blade to cut.  Just hold the jigsaw firmly and let the blade do the work.  I also held the windshield very firmly and close to the front of the cutting blade to eliminate any jumping that could happen from snagging.  If the blade snags it could cause the plastic to chip in that spot.  Snagging will usually occur from a dull blade, pushing it along to fast trying to force the blade to cut faster than it is able, or a blade that is not fine toothed enough to cut the material.  Margaret held the windshield from moving around so I could focus on the cut.  Just follow the tape line around and try to keep it as smooth as possible.  You might not get an absolute perfectly rounded cut but you’ll be sanding any points or other imperfections afterwards.

When you get about ¾ of the way around you'll want to stop cutting.  Your gonna want to cut the big rounded piece you've been working on off.  The reason for this is to prevent the plastic you've already cut from snapping off due to the weight which could cause damage to the windshield.  After you do this continue your cut on the remaining small piece until your done.

Now I took off the tape to get a better view of the cut and began sanding the edge with 100 grit sandpaper using an electric sander.  I used the 100 grit to smooth any areas that might not have been rounded well or any points that I needed to blend.  When I was happy with the shape I moved to 400 grit and used this one to begin rounding the edges to match the original cut.  I finalized the sanding with 600 grit without using the electric sander.  Doing this allows you to feel any rough spots with your hand that you might need to go back to using a courser sandpaper. 

 Before sanding the edge

Closeup before sanding

I tried to get another closeup of how well the edge looks upon completion.

And thats it!  The whole job took about 2 hours and came out well.  She's ridden with the shorter wind shield 3 times and is very happy with the results.