Another windshield experiment

[2005c6]

I posted this on the "Unbelievable" thread as well, but realize some of ya'll might be done looking at this thread, so I thought I'd post a new thread:



I tried another experiment this afternoon. I took the windshield completely off, and rode for about 20 miles. Now, strickly in the interest of science, I even made one run over 100mph (that's SOP for me ).

The wind noise was much better. Yes, like on any motorcycle with no fairing, I was getting a full blast, but that "high velocity" air normally coming off the top of the windshield was no longer there, and the general wind noise around my helmet was much more subdued. Up until the ST, I had never owned a motorcycle with a fairing anyway, so I have no problem riding without one.

I think what I want to do now is cut a windshield down as low as I can so it looks right over the front of the guage shroud, and maybe even tint it. Then use a stock windshield for winter riding. If anyone has a windshield they want to get rid of cheap, let me know (stock or otherwise). I don't want to pay much because it's still in the experiment stage.

Anyway, pulling the windshield off is really easy, so ya'll might want to try this as well.

[STPilot]

Jim

I just grabbed a used aftermarket shield to do exactly what you described. I'm gonna start by wackin off the top, 2 inches at a time and see what happens. :D

[steve18]

Jim,
Is adjusting the windscreen up on the brackets pretty easy? I tried to find some posts describing how to do this and couldn't find any.

Steve

[2005c6]

Jim,
Is adjusting the windscreen up on the brackets pretty easy? I tried to find some posts describing how to do this and couldn't find any.

Steve

Yes, it's very easy. Once you know the sequence, it's about a five minute job. You unscrew the four phillips screws that you see holding the black plastic covers over the brackets (BTW, this whole job should be done with the windshield in it's full up position).

Then, you will see four 10mm nuts holding the windshield bracket to the adjusting arms. Just loosen them - do not take the nuts off. Then you can slide the top part out of the slot, and move it up to the other slot. The bottom part just rides up in a closed slot. This will be very obvious when you look at it with the plastic covers off.

When putting the plastic covers back on, be carefull not to over tighten them - you are just screwing into plastic.

[Fireball18]

As an alternative, and a way to get two extra positions out of the fixed windshield you can do this: Remove the black plastic beauty covers, then remove the windshield itself using an 8mm socket. Set aside carefully. Then, using a 10mm socket, remove the nuts that hold the windshield brackets in place. Turn them upside down and replace them on the opposite sides--left to right, right to left, adjust to upper or lower and tighten the nuts. Just make sure you adequately tighten the bolts as the brackets will be upside down and the little "hook" won't be resting on top of the threaded screw shaft. So far, in 2 years, I've never had anything slip. The only thing different you'll notice is that at the top, when you replace the black plastic covers, the top of the bracket will be slightly above the inside black cover. No biggie. This gives you a high position that is slightly lower than the stock high position and a low that is slightly lower. You now have 4 instead of 2 windshield positions to choose from.

[DataDan]

Very interesting data point. Contrary to popular belief, and in agreement with your experiment, windscreens create wind noise, they don't reduce it. The alternatives are: little wind noise but lots of wind blast, or little wind blast but lots of wind noise. The noise is created where there is turbulent flow at an edge the separates high pressure (the front of the screen) from low pressure (the rear of the screen). A windcreen that reduces wind blast will necessarily create turbulence and noise. (On a bike like a Gold Wing, noise is reduced because the turbulent flow is well above the rider's head.)

Honda tries to minimize turbulence by feeding high-pressure air from the base of the screen, via a vent, up the aft side of the screen, reducing the pressure difference at the upper edge. But that goes only so far, and the difference can't be completely eliminated.

Fourteen years ago I experimented with my silver '91. I was annoyed by the wind blast and wanted to see why the vent wasn't doing what it was supposed to do. I taped short lengths of yarn to the inside of the screen and took the bike out to "the people's wind tunnel" (aka Interstate 680). I found that the vent created nice flow up the aft side of the screen, but 4 inches from the top, the flow separated from the screen. So the fix to make was pretty obvious to me: chop 4 inches off the stock windscreen.

After cutting down the screen, I again ran a wind-tunnel test and found that air was flowing all the way up the aft side and joining flow over the top nicely. Noise was decreased, and, though my head was in the airstream, it was smooth-flowing air, not the turbulence that previously came off the screen.

Before cutting down the windscreen on your ST1300, I would suggest a similar experiment. Find out far up the back side air from the base flows smoothly, and cut there. If you need to cut more, you can. But see how it works with a minimal cut first.

[steve18]

Thanks for the info! I will try it today.

Steve

[sherob]

My ride in this morning was interesting. Was able to keep the sheild lower than normal... no pressure, noise seemed less too, and MPG was higher(~45 @ 85mph). After looking at the sheild when I got here, it seems there is a wider gap between it and the front tupperware than before moving the brackets up... IIRC. :)

[NormanPCN]

Before cutting down the windscreen on your ST1300, I would suggest a similar experiment. Find out far up the back side air from the base flows smoothly, and cut there. If you need to cut more, you can. But see how it works with a minimal cut first.

That depends on the shield angle. The stock bottom vent is very restrictive. If you open it up and with the shield all the way down the airflow follows the back of the shield all the way to the top. Even on my +6W+2H CB shield.

[2005c6]

Great information from several of ya'll. Thanks!

[tdeboeser]

As an alternative, and a way to get two extra positions out of the fixed windshield you can do this: Remove the black plastic beauty covers, then remove the windshield itself using an 8mm socket. Set aside carefully. Then, using a 10mm socket, remove the nuts that hold the windshield brackets in place. Turn them upside down and replace them on the opposite sides--left to right, right to left, adjust to upper or lower and tighten the nuts. Just make sure you adequately tighten the bolts as the brackets will be upside down and the little "hook" won't be resting on top of the threaded screw shaft. So far, in 2 years, I've never had anything slip. The only thing different you'll notice is that at the top, when you replace the black plastic covers, the top of the bracket will be slightly above the inside black cover. No biggie. This gives you a high position that is slightly lower than the stock high position and a low that is slightly lower. You now have 4 instead of 2 windshield positions to choose from.

Darn it, Fireball18!!! :) I just got done moving my shield. It looks to be a little higher than i like. So now i'm gonna go back out in the heat and try your solution. :p:


Tom de

[tdeboeser]

Are there torque specs for the windshield parts?


Thanks

Tom de

[AgSTreak]

Of course I had to play with my windshield too on this weekend's 300+ mile ride, thanks Bob. Tried it set both high and low with the windshield at its lowest electrical setting. Locked high, the turbulence and wind noise were reduced quite a bit but the view over the top was also reduced along with the air flow. Fewer bugs hit my faceshield (Note: I have a Laminar Lip) which was also a plus.
Bottom line:
For long distance trips, I will use the high setting.
For short trips and commuting i'll go with the lower setting, until the weather cools.

Good catch, Bob :yr1: :yes: .

[vnsfxr]

Jim

I just grabbed a used aftermarket shield to do exactly what you described. I'm gonna start by wackin off the top, 2 inches at a time and see what happens. :D

Tim,

Keep me posted I'll probably follow your lead on this.

Vince

[tdeboeser]

Thanks Greg!
Just got in this morning, after moving my stock shield per Greg's (FireBall18) suggestion. For me it's an improvment. I still get air to my face and body, but there is less buffeting. With Greg's "bracket turn-over" the shield doesn't block my view (I'm 5'8"), and I can feel the air coming in behind the shield filling the void between the shield and I. I was able to test this at 90mph.

I havn't played with adjusted shield hight via the controls, maybe on the way home today.

Tom de
'03 St1300 :03biker:

[Marshal_Mercer]

Raised my shield to the top bracket position. Gas mileage went from 45 to over 51 MPG! Huh? Must be all of the noise dissipation.

Marshal

[Fireball18]

Thanks Greg!
Just got in this morning, after moving my stock shield per Greg's (FireBall18) suggestion. For me it's an improvment. I still get air to my face and body, but there is less buffeting. With Greg's "bracket turn-over" the shield doesn't block my view (I'm 5'8"), and I can feel the air coming in behind the shield filling the void between the shield and I. I was able to test this at 90mph.

I havn't played with adjusted shield hight via the controls, maybe on the way home today.

Tom de
'03 St1300 :03biker:
Tom, Glad that worked for you. :D

[STPilot]

Tim,

Keep me posted I'll probably follow your lead on this.

Vince

I will, I'm gonna try it out this weekend. :D