A n00b building a mini rally fairing for a 690

Discussion in 'Thumpers' started by jaTillApan, Apr 14, 2013.

  1. jaTillApan

    jaTillApan Adventurer

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    I want some more wind protection on my 690 enduro for longer trips. The problem is I haven't really been able to find a fairing that is both good looking and affordable. I really like the look of the Rally Raid kits with tanks and all, but it's just too expensive and also a bit on the heavy side. And for a sexy bike like the 690 it would be too painful to go with a cheap but ugly solution. So I came to the conclusion that it might be best to try to build my own. I have never done anything like this before though, so all feedback is more than welcome!

    My plan is to build the fairing out of carbon fiber and attach it somewhere at the fender, forks, handlebar clamps or whatever suits the design I settle with. As I don't have access to a workshop I think the mounts will be the hardest parts to fabricate so I want to keep that simple.

    Well, lets get to it!

    Yesterday I took some measurements on the bike, did a quick flat paper mock up just to get a sense of scale, and started to work on a first design in the computer. After some negative feedback and a good nights sleep I realized it was actually quite ugly. So I started over today and came up with this design that (at least at the moment) I'm quite happy with. As a first draft that is... What do you guys think? Feel free to feedback on everything: aerodynamics, design, construction etc!

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  2. sprouty115

    sprouty115 Long timer

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    Style is a personal choice, so if you are happy with it that's all that matters. My only thought would be to make a mock-up (cardboard?) that can be mounted to the bike so you can play a bit with the height and width to see if you're happy with the wind protection. Sometimes a little adjustment can make a big difference in turbulence.
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  3. Dino de Laurentiis

    Dino de Laurentiis Working on it

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    Are you sure that's the best design for a clean airflow?
    Sharp angles aren't necessarily the best way to move air smoothly. It's also quite similar to the 990 Adv fairing (only bigger), and lot's of people complain about horrible turbulence on those.

    I really shouldn't knock it's aesthetics... ...but I really can't help it :p
    It looks a bit unproportional (i.e. too big) to the size of the bike, and it's overall triangular shape, coupled with the headlights, make it look a bit like a Ku Klux Klan hood, only orange :D Form should always follow function of course.
    #3
  4. WildmanSam

    WildmanSam Been here awhile

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    the ku klux ktm :rofl
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  5. jaTillApan

    jaTillApan Adventurer

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    Haha, thanks for the feedback guys!

    I'm having a bit of a struggle to get it to look proportional to the bike. I guess that's part of the reason they build the rally kits to go all the way around the forks and attach at the "tank". To be able to make it high enough without looking stupid :p Because this one isn't particularly high. It just looks that way because the entire bike is so narrow. But I guess I should try to lower it a bit and make it a little wider.

    And talking about aerodynamics I have no idea what's the best design, so that's good feedback. I should read up on the 990 adv fairing!

    And it's interesting how much your view of things changes when you step out of it for a few hours. Now it doesn't look nearly as good as it did yesterday :p
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  6. sprouty115

    sprouty115 Long timer

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    One other thought occurred to me, and it's another good reason to do a mock-up - line of sight. The taller the fairing the longer the forward blindspot is. Which means that if you miss seeing something in the road you may not know it until you run it over.
    #6
  7. jaTillApan

    jaTillApan Adventurer

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    At first I did a quick paper mock-up and realized I could live with something reaching 60 cm up from the fender. This one is about 55 cm, so it should be alright. But yeah, once I've found a design I like I'll build a cardboard version to see it in real life. I guess that will be the real test. A 3d render can only get you that far...
    #7
  8. Sean-0

    Sean-0 straya carnt

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    have you thought of keeping the height but using perspex as the top part of the faring :deal

    i am in the process of doing such here is my first try

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    used to be fiberglass to almost the top of the perspex ..i cut it down and added the clear ... it still needs work and then the better 1 will be made ...you can add slots to the bolt mounts to make it adjustable up and down to suit

    just a thought
    #8
  9. jaTillApan

    jaTillApan Adventurer

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    It's a good idea, but it adds to the complexity of the project. And I'm afraid I might end up with something half finished sitting in my apartment for the entire summer if I try something too ambitious...

    But it's an interesting shape of that screen! It's a pretty extreme lip there at the top. How's the airflow from that one?
    #9
  10. Motomochila

    Motomochila Mad Scientist

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    You are going to have serious issues with that design unless you also design a mounting system that welds or clamps to the head stay. Mounting to the forks or triple clamps would not give you the desired wind deflection you are seeking. Have you looked at the lynx fairing? Although smaller, it does have a movable windshield that works quite well. At least look at the mounting process the lynx uses to aid you in your design.

    Keep posting as you go forward.
    #10
  11. jaTillApan

    jaTillApan Adventurer

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    From what I can figure out the lynx fairing attaches in a similar way to how I want mine to attach, turning with the forks. What do you think would be the problem? Will mine be too high and wobbly? And the wind protection can hardly be affected that much by how you attach the fairing, right? In speeds where you need a fairing your forks will hopefully point in the same direction as you are going :p Or am I missing something?
    #11
  12. jaTillApan

    jaTillApan Adventurer

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    Trying out a smoother and lower design today. Maybe a bit more proportional to the bike, and less orange Ku Klux Klan :p

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  13. sprouty115

    sprouty115 Long timer

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    That looks pretty good. And I'm not really a fan of any fairing, so that's high-praise.
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  14. Jan from Finland

    Jan from Finland Been here awhile

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    I wouldn't worry about sharp angles. The whole point of a fairing is to create disturbances. It's not an aircraft wing. It's practically impossible to predict how well it works in your case by just looking a picture. You have to test it first. If fairings were designed to minimize turbulence we were all riding bikes with dustbin fairings.

    Here is what KTM has come up.

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    #14
  15. Bruno T .

    Bruno T . N8YQ

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    The trail tech above ^ bit taller might look decent. Not too tall though.
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  16. jaTillApan

    jaTillApan Adventurer

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    Thanks for the feedback!

    I tried something like the trail tech design but taller and it looked like shit :p And after riding 200 km yesterday I really feel I want the fairing to be as high as possible. Maybe I have to sacrifice some aesthetics for better comfort...

    Here is something in between the first two designs:

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  17. Skibikejunkie

    Skibikejunkie Adventurer

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    Says a lot about the affordability of aftermarket fairings that you can fab one out of carbon fiber and still have less out of pocket.

    I must have a lousy sense of aesthetics, because I've liked all your design mock-ups.

    Do you plan on incorporating your existing headlight, or will you be adding an aftermarket light along with the fairing?

    Cool thread--will definitely follow along on the journey.
    #17
  18. jaTillApan

    jaTillApan Adventurer

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    Thanks for the encouragement! It's well needed!

    I actually don't think this will be a lot cheaper than buying a similar sized fairing. Maybe the Lynx one is a bit on the expensive side, but it's also more complex with the adjustable windscreen. And the more I read up on carbon fiber manufacturing the more nervous I get. But even if I try and fail I hope I learn something in the process...

    I'm thinking of upgrading my headlight to get a better high beam, so I will probably not use the original one. At the moment I'm looking at HIDs, but they are really expensive. We'll see what I can find... If I end up with a design that supports the original headlight I guess I could use it in combination with another high beam on top of it. That might actually look cool. Thanks for making me think about that!
    #18
  19. jaTillApan

    jaTillApan Adventurer

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    I saw a picture of this guys bike some time ago, and now I finally found a tread about his build. I think his fairing looks great:

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    #19
  20. Motomochila

    Motomochila Mad Scientist

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    My Lynx attaches to the lower clamp and the bar mounts. I had to fab up a completely new mounting system to hold the fairing in place. Way too much wobble and rattle in the dirt. I eventually dumped it for a Baja Designs modified Stryker. Still haven't designed the wind deflection tho...

    I would first design a mounting clamp system to the forks directly. two mounts on each side. Aluminum fitting with simple hose clamp similar to Baja Designs race lights mounts. From this you could easily get the rigidly you will need to support the fairing. Pavement riding is not the best test once you get a design working. Off road you will find every flaw in your designs; cable placement, light bracket mounts, connections to the brackets, etc. Build your first prototype in cardboard with drywall mud, yea drywall mud, mixed with Elmers glue. It is easy to shape and can be painted and polished far easier than bondo to make you mold. I built several parts this way for vacuum molding and fiberglass molds back in the 80's for bullet fairings and storage boxes on knee draggers. Its also much cheaper when you toss your design out when it doesn't have the look you want. Also consider LED lights from Baja Designs instead of HID's. Far lighter making for less issues off road. The Stryker light works very well.
    #20