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How To: Cut Down a Windscreen
Below is a detailed description (and photos) of how to cut down a full size Vespa screen written by Delaware Don and then, after being followed by myself, slightly edited and added to in order to enhance (I hope) the methodology. My additions are added between the ** marks. Many thanks to Don for doing most of the hard work. Now, over to Don…

Like many of us, I sometimes learn by trial and error. Such was my experience when choosing a windshield for my new GT200. My first purchase, given the way it looks, was to buy and install the smoke FACO mid-sized. It looked great, but directed the flow of air, given my height, just at ear and eye level, resulting in an incredible increase in wind noise and produced such tearing in my eyes (I wear glasses under my 3/4 face helmet), that it was truly unsafe to drive at anything above 40 mph.

My second purchase was the Vespa Tall....and tall it is! I looked through the windshield....not over it. Distortion wasn't bad, and wind noise was almost non-existent. In addition, the shape provided some additional protection for the hands during cold-weather riding. However, looking through the windshield produced poor visibility during rain, especially at night. In addition, the height of the windshield produced some bending and fluttering of the lexan at speed. And finally....there was that warning sticker that indicated the scooter to which the windshield was attached should never exceed 100 kph (approximately 60 mph).

My solution? Cut down the Vespa Tall Windshield. During my 40+ years of motorcycling, I learned that if you could peer over the top edge of any windshield and see a spot approximately 25-30' ahead of you on the road, the windshield would be of correct height. So....out into the street I went with GT200 and measuring tape. Picking out a spot at an appropriate distance ahead, I measured down from the top edge to the point where I was looking through the windshield. For my height (5'11"), that point was 4.5" below the top edge.

** At this point I should add that I had just added the tall Vespa screen to my GTS. The screen included the rubber edging around it which I do not like at all and was hoping to remove. My cut point using the measuring above was 13.5 inches above the headlight (I am 5’ 11”) **

Back into my garage I went, and performed the following (**I don’t have a garage, but the garden table was sufficient and I added a towel for protection**):

1, Removed tall windshield, leaving brackets in place.

2. Placed blue painters tape in a swatch about 12" wide over the place where I estimated the cut would be made. (The tape will prevent the foot of the jigsaw from scratching the lexan, and will also produce a cleaner cut).

3. I made a paper template by tracing the top contour of the windshield onto construction paper. Then marking a spot on the tape about 4.5" from the top, traced the contour onto the blue tape so as to have a line to follow while making the cut.

4. I carefully cut the new contour using a fine-tooth blade on my jigsaw (24 teeth per inch), being very careful not to hurry and to let the saw be the one who did the work.

** Here I made a few adjustments to the above points. Firstly, in relation to point 3, rather than tracing the outline I came up with the idea of making a test cut about an inch above my intended cut. This would allow me to test the blade I was using, see the quality of the cut, get used to cutting the Perspex and give me a real template to use to mark the real edge for my cut. I had bought a special Perspex blade for my jig saw and it cut OK on the test cut but half way through the dust from the cut was falling into the cut line and fusing against the heat on the blade causing the Perspex to stick itself back together (*you could spray the blade with water as you cut to solve this). The cut was thus a bit of a sticky mess. I then changed to a general but very sharp blade (as photographed). This cut almost like it was through butter and gave a really smooth finish (see the two pictures below). With the test strip I could draw a cut line with a bit of moving the strip as the screen is wider here than it is at the top. I then tried drawing a line with my small sports screen and this had a better profile to it for the cut anyway.**

5. After cutting, I left the tape in place and attached the windshield to the mounting brackets.

6. Using a sanding block and medium and fine sandpaper, I smoothed all the freshly-cut edges and made minor adjustments to the contour until I was satisfied. I then removed the tape, cleaned the windshield and went for a test ride.

** I used various sand papers from about 200 grit up to about 1000 grit for the final finish. I was able to get a perfect finish and removed the glue from the edging that was on the original shield. I also smoothed the edges to a slightly rounded shape by running some fine paper at an angle of about 45 degrees to the screen. This would make the edges much less sharp (and dangerous) and also may serve to reduce wind noise at high speed.**

My test ride was in 65 degree weather with a light rain and 25-30 mph crosswinds (Ernesto approaches!). The wind noise was almost non-existent, just like it had been before the cut-down. The air flowed up and over the top of my helmet, carrying most of the rain with it. If I wanted to, I could "slouch" just a little and eliminate all the effects of the rain on my helmet and face. I had road room to achieve a speed of 65 mph, and felt absolutely no ill effects on handling, even with some pretty substantial cross winds. I would feel very comfortable using it at any speed up to the GT's advertised maximum. Finally, almost all of the lexan flex and flutter had disappeared, given a reduced surface area with the same supports.

All in all, I am very pleased with the results, and also feel that the size of the cut-down tall Vespa shield is now much more in proportion to the rest of the machine

** My test rides were great too, even full speed (sort of) rain test. There is no fluttering about and I think the overall look of the screen is much better than with the high screen. You can judge from the pictures below.**

Delaware Don and London Charles!

Part 1: The ugly full size screen (minus the edging)


Part 2: Taped and ready to cut


Part 3: After the test cut (rough edge, wrong blade)


Part 4: The smooth main cut with the right blade


Part 5: The right blade...


Part 6: Close up - smooth edge!


Part 7: Finished, looks much more in proportion now!
Last Updated Thu Jun 12, 2008 1:53 pm
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