Windscreen Buffeting

[Radioguylogs]

I put a National Plexifairing 2 on my SF over Thanksgiving.



With 47 degree temps today, I had a chance to try it out.

Buffeting is unmerciful over 50 MPH.

Any hints about setting it up to minimize buffeting?

[Prisoner6]

Hi, Mike -

Go for another ride, and experiment with your riding position.

In other words, move around a lot during the ride (slouch down, sit up as tall as you can, move forward/rearward, etc.)

If you can find a sweet spot that minimizes or eliminates buffeting, it will tell you whether your screen is too tall/short and/or too close/far away.

It sounds to me like your windscreen is, at the very least, too short for your height in the saddle ...

Creating air flow directed squarely at your head, instead of over it. If your windscreen mounting is adjustable, even a 1" height adjustment can make a difference.

[TADracer]

You might find that the little wings that pop out in front of the grips may be the culprit.

I have no proof of that other then I had a shield very similar to this mounted on my SF several years ago and experienced the same thing. I tried a lot of different positions until I finally took it off and hung it up in the shed. A few years ago during a frame-off remodel I decided to cut the shield down into more of a bug screen. Buffeting gone. I am tall but in spite of the small size of the shield it takes all pressure off of my chest and throws the Windstream about an inch over the top of my helmet. I have had it over 110 and can ride sitting up just nicely.

But still, you should try using all the different mounting positions allowed by your shield to see if you can get the sweet spot.

[Radioguylogs]

Thanks for Suggestions

Marco:

I did try various head positions during the hour that I was riding yesterday.

When I ducked down or moved closer to the windshield, the buffeting improved.

When I stuck my head up, it got worse.

So, based on the remarks so far, there is probably not some magic angle or trick; just simply move it up to make the air go over me as much as possible.

The current height of the windscreens seems just right, as it is about the same height as my nose when I sit comfortably. Seems like I may have to make a compromise.

Mike:

Your experience with the hand grip shields is quite surprising and interesting.

[crazy steve]

My experience is the top of the windshield should be be right at eye level (so you're just looking over it). Even small differences can have big effects. And tipping it back (so the top is closer to you) will help. As has been pointed out, how you sit on the bike has a lot to do with it, and not every windshield is effective for every rider.

And the helmet you wear will effect this; I use an open-face helmet, and when using a 'bill' type visor I get more buffeting.

[jetmechmarty]

I have the Plexi 3 on my Special. Steve is right about the bill. Also, you have to tilt the screen back a bit. It should at least follow the angle of the forks, if not more.

[IanDMacDonald]

I think you have it too low Mike. I have "whatever is in my sig", and I have a nice gap between the headlight and the windscreen. An awesome shield I have for the Fall.

[Radioguylogs]

Move it Higher

I appreciate the helpful information and suggestions.

It's helpful to hear that eye level works for Crazy Steve.

I was thinking Marty might be able help because I remember seeing the windscreen on his Special, and I liked the shape except for the lower portion.

Marty: Considering how low you mount your handle bars, and your physical height, you must have the top windscreen brackets up above the bend on your handlebars? It doesn't seem like I could go any higher below the bend, and it seems doubtful it would mount correctly over the bend, so I need to move the brackets up above the bend?

My windscreen rake is barely more than the forks, maybe I could try a little more. It should happen automatically if I move the brackets up further on the handle bars.

[kboehringer]

It should at least follow the angle of the forks, if not more.

Mike,
I have barely minimal experience with a windscreen compared to most others here. I do have one and plan on purchasing another very soon for my other XS11. At first I had it too "Tall" and I experienced buffeting. I followed Marty's instructions on mounting (he provided me last year) and moved it to a slightly greater angle than the forks..... NO more buffeting, gone completely!

I wear a full-face modular helmet and like to look cleanly over the shield. Personally, I also prefer the shield at nose level.

KURT

[jetmechmarty]

I appreciate the helpful information and suggestions.

It's helpful to hear that eye level works for Crazy Steve.

I was thinking Marty might be able help because I remember seeing the windscreen on his Special, and I liked the shape except for the lower portion.

Marty: Considering how low you mount your handle bars, and your physical height, you must have the top windscreen brackets up above the bend on your handlebars? It doesn't seem like I could go any higher below the bend, and it seems doubtful it would mount correctly over the bend, so I need to move the brackets up above the bend?

My windscreen rake is barely more than the forks, maybe I could try a little more. It should happen automatically if I move the brackets up further on the handle bars.

It's hard to tell where yours are mounted, but mine are mounted somewhere in the middle, between the bends.

[Radioguylogs]

Not sure

It's hard to tell where yours are mounted, but mine are mounted somewhere in the middle, between the bends.

Marty:

Maybe you could take a peek at my first post.

"In the middle, between the bends" means not 'on' the bends, but 'inside' the bends, like where I have them?

Thanks for your help

[madmax-im]

I cant really see where this screen is off the mark...so to say...its positioning looks quite similar to how mine is mounted...and for me it works fine without buffeting...but i am only 5'9"...if you are much taller then I suspect the screen itself isnt tall enough for you....but position wise on your bike it looks to be correct...without seeing it in person one cannot say with certainty that it is correct...I guess you'll have to play with it some more...LOL

[jwhughes3]

I think if you take it up another 1-2" and create a better gap near the gauges that may also help by sucking some of the air up the backside.

I had a Plexifairing 3 which is taller and it did wonders for my head buffeting. On my Windjammer I added the extra tall windscreen for same reason.

John

[XJOK2PLAY]

If you find that the shield is a bit too short, you might add a Laminar Lip to the top to extend it and redirect the airflow.

On newer bikes, (like my C14,) they also form the bottom center of the shield with a "U" shape. This allows air pressure under and behind the screen, which eliminates buffering.

I agree with what was said earlier about the best height...
If you can get it to just below your line of sight it should reduce/eliminate the buffering.

I use 2 different shields on my C14. For cold or rainy weather, the Cee Bailey's High Dome Ultra Tour... (it's tall and wide.) No buffering.
For summer heat, a low profile sport shield called a CopperDawg. It's low, laid back, more like a sport bike. But, it was created by a guy who rides a C14 and lives in Florida. It's design is such that aims the air flow straight at my chest, but is streamlined in such a way that it's a steady flow. Regardless of speed, no buffetting.

Shape, height, position... all come into play.
But, if it's just a bit too short, a Laminar Lip might solve the issue.
Bob

[Radioguylogs]

More ideas

Bob: Thanks for your thoughts.

I haven't tried anything more yet because it has been so cold recently. It was -4 degrees on Sunday morning, and we have had constant snow flurries for a week, but no significant accumulation.

I suspect the air flow under the windshield might be a big influence as you suggested.

Hopefully I won't need a Laminar Lip, because this windscreen works for a lot of people....but it's an option.

I will be trying these ideas as soon as I can get another weekend day near 50 degrees. The temps might cooperate this weekend, but I will be 'up north' as we say in southern Michigan.