The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Danno on May 15, 2008, 01:15:41 PM
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Hi everybody. I've been riding on and off for 40+ years but am new to the BMW world and this forum. I found an exceptionaly clean 84 R65 with 34K miles and fits me (5'10") and my plans (commuter) perfectly. I reinstalled a aftermarket windshield that the seller gave me and am now plagued with bad helmet noise. I've been playing around with raising, lowering, tipping it back etc but am not satisfied. Is there a rule of thumb regarding windshield height? It was at eye level but by tilting it back it's a couple of inches lower.
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Screen selection is very much a suck it and see thing. Different bikes, screen design, mounting, rider height, helmet design, wind direction/strength and travelling speed all play a part that has one biker at 5'3" loving one screen while a 5'10 rider is suffering, or even vice versa!!
Some screens end in a flat edge that creates eddy currents, others have lips or even laminar lips that try to lessen those eddy's. Making a combination laminar lip if you have a flat edge screen may work, it's easy to find out.
You will need a piece of material, preferably perspex the same thickness as the screen, about 40mm deep and almost as wide as the top of the screen. A couple spacers clamped either end to hold it about 15 - 20mm off the surface and angled so it deflects the air up and over the edge of the screen and can break those eddy's and hopefully send the wind over your head. May or may not work, but the only other alternative is lower bars to lower your riding height, or a higher screen.
Send a pic if you can so we can see what sort of screen it is and better give advice as some are a lost cause.
Bill............................;-)
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.... Or, you can cut the screen lower in height so that you get a full stream of wind right into your face/neck - it creates MORE wind
on your head/upper chest that you have to fight, but the idea is to get the air flow to be smoother/less turbulent so you don't get
the buffeting/inconsistent air friction.
My Concours has a lip on the upper edge that does a fairly decent job of flipping the wind up just enough so that it hits the top of
my helmet, and I can look over the top edge of the screen while in normal riding position.
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I, and I think most riders, like to look over the top of the windshield. Mine are adjusted to be about 2 inches below line of sight. the additional noise could also be reflected engine noise. As far as wind is concerned you can actually feel where the air flow is at speed by moving your hand up and down behind the windshield and feeling for the edge of the airstream. Then move your head up and down to see if there is a change in the amount of buffeting and noise you get. Then you can adjust the windshield to a corresponding position. this is strictly an adjust and try labor. You don't say what kind of helmet you are wearing - there is a considerable difference in helmet wind noise. I tried a HJC modular and returned it after 2 miles - it was just too noisy compared to my full coverage Shoei (no I don't want to start a flame war). YMMV.
I'll be looking for a new helmet soon. Perhaps I should start an inquiry into what is the quietest helmet.
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I've got a Laminar Lip coming that I want to try before I fire up the saw.
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I prefer shorter with some really good custom earplugs (with speaker in 'em - gotta have my tunes) :D
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Got the Lam Lip the other day. Very noticeable difference. Still need more highway time to dial it in better.
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Where'd you get the modified windshield Danno?
My Rifle fairing needs 3 or 4 inches added, or subtracted, or a lip (I think).
Ed