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Old 01-18-2007, 07:27 PM   #1
ehatcher OP
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BMW GS650 Dakar project

This is my 650 Dakar that I just finished putting together. The new bodywork is all carbon fiber and Kevlar and held on with ¼ turn fasteners, all the fairings can be removed in a few minutes. The bodywork is considerably lighter and simpler than the original; the oil tank/plenum fairing is one piece (as opposed to the three pieces of the original) and so is the rear fairing. The front instrument/headlight pod is supported with a single aluminum truss (it does not shake or vibrate as the original did, and the truss is about half the weight of the steel thing BMW had inside).


The left headlight is a bi-xenon HID and the right is an amber halogen by Hella. The HID is like a flamethrower – gives great light and makes night riding a reality. The combination of 2500K amber and 5000K white lights makes the bike VERY conspicuous. There is a switch that allows either to be turned off; the amber so I get enough juice to run all my heated gear, the HID so I get better visibility in crappy weather (I don’t care about the theories: amber works well for me)


The taillight is an LED trailer light, much brighter than stock and about a quarter of the weight and much less current draw (and a bargain at twenty bucks!). Turn signals are KTM.


The bash pan is fabricated from 1/8 aluminum and TIG welded together, it is quite strong. I will probably cut some vent holes into it eventually.



Overall, quite a bit of weight was lost along the way from stock. The bodywork was a big chunk and next the single exhaust. There is a couple of little brackets and crap inside that got redone in graphite. The bash plate, HID ballast and Powerpegz were all heavier than stock stuff but worth the weight for my uses. The weight loss is noticeable when riding. Feels like more power and it is easier to horse it around offroad.

The engine is stock (for now) with KN (different snorkel), Staintune and Techclusion: actually these three together really woke the engine up and I am pretty happy with it now. It does not feel like much more top end power, but the midrange seems very much increased, 2nd gear wheelies are now very easy to do, and the power change characteristics make the bike more fun to ride.

I never much cared for the looks of the original 2003 Dakar. When I bought the bike in May of 2005 I bought it with this project in mind. I liked the ABS and the solid Rotax motor. After owning it for a while I was sure I made the right choice. For the majority of riding I do, this bike works very well.

I really liked the look of the Honda Africa Twin (you knew that already), but as I spent time looking at it, there were a couple of things about the AT that I felt I would do differently. First, I wanted to integrate the bash pan right into the fairing, ala sport bike. Next, and most important, I wanted more curves, which some of the GS bodywork already had, along with an interesting looking seat (as opposed to the AT’s square looking setup). I had about fifty pictures of various bikes, mostly ATs hanging on the wall of my shop when I started mocking up bodywork. I decided early on to keep the scalloped inlets and trim from the original GS; they were the only things I ever liked about the look of the original bike. Keeping them also made the bike instantly recognizable to its heritage, which appealed to me because it gave the bike a “factory” look.

I struggled with designs for the rear end, I originally wanted a full fairing that came forward and met with the front fairing, but it always looked clunky in sketches and when I mocked a few up on the bike they looked worse. They were also all heavy and complex to support. I finally settled on a very simple design that kept some of the original look, but it is overall much lighter (probably the single largest area of fairing weight loss – there is a LOT of crap bolted together back there on the stock bike).

On close inspection the paint is less than perfect, but I was not going to expend the time and effort to make a “show” bike and subsequently beat the heck out of it on trails, gravel roads, creek crossings etc.

I am not finished. The suspension is next on the list. Also, I am going to continue to replace stuff with carbon fiber, the plenum comes to mind as the next target, the stock one and its mounts are very heavy. I am also planning a rear rack. There is an aluminum storage pod that goes where the right pipe was, but I have to finish the mounts for it, also I am planning a 3 gallon reserve tank that it will interchange with (for long distance trips). I have a one piece graphite front fender that I made, but it is taking considerable time to finish and mount, so I will work on that this summer. I will also make a graphite inner rear fender when I get the time.

One cool thing I did not originally realize was that I have the molds for all the painted bodywork, this means I could make up another set and have a different paint scheme if the mood strikes me. This would not be and easy job as the molds are not production grade, so the finished parts take a lot of finish work, but it is possible.



The GPS is mounted as high as I could get it; I barely have to take my eyes off the road to see it, I am happy with its placement. The carbon fiber dash panel incorporates the mounts for the instruments and also acts as a bulkhead for the rear of the fairing.

The windscreen is the stock part trimmed to fit. It is mounted with screw jacks that allow it to be adjusted up and down for comfort. By sheer luck, there is no buffeting evident at any height.



I have built a lot of projects over the years, furniture, boats, custom bits for aircraft and cars, models, etc. However, this is one of the best projects I have ever done. I open the garage door and a big smile forms on my face. In the past, I have dreamed of a bike like this, but dreams are funny, we see things in them that defy exact dimension. When you awake and try to sketch the thing you saw in the dream, it somehow becomes elusive and you are left with only the feelings you had about it in the dream. Perhaps you recall a few inexact details such as “it was yellow” and “it had twin headlamps.” That said, this is the bike I dreamed of, and I know it not because of the exact details of its construction, but because of the feeling it gives me when I look at it, it is the same feeling I had in the dreams.

Some building pics:

Fitting the bash pan


Truss for the headlight assembly


Fairing prototype



Fairing prototype pieces


The mold for the main fairing



TIG welding the mounts to the bash pan




Eric
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My Dakar http://www.advrider.com/forums/showthread.php?t=197573

ehatcher screwed with this post 02-03-2007 at 11:10 AM
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Old 01-18-2007, 07:37 PM   #2
Cycletroll
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Verrrrry nice! You could probably sell those kits to some of the folks here at ADVrider.
Just curious, any change in how the aerodynamics feel at speed? Smoother? Better protection? Top speed?
Anyhow, nice work. I always really liked my Dakar. I think someday if I find a cheap used one I may try to "improve" it a bit .
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Old 01-19-2007, 12:08 AM   #3
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Originally Posted by Cycletroll
Just curious, any change in how the aerodynamics feel at speed? Smoother? Better protection? Top speed?
I used to get some light buffeting on my helmet, now thats gone, I suspect thats because the windscreen is a few inches higher. I have not really done a lot of riding with it yet to know if anything else changed. I was really worried about it (buffeting) having read in these forums about the struggles riders have with some designs. I sought advice from several people about the causes of buffeting, the best insight came from WPBarlow who suggested that buffeting is caused more by the bikes total presentation to the wind rather than just the windscreen, so when it was in prototype form I took it up to 90 to see if there would be buffeting issues. By sheer dumb luck, there were none. In fact, the windscreen is very adjustable and it had none in any position, it was buffet free no matter what I did, so apparently the advice was accurate. Until that test run I worried non stop that I was going to a lot of trouble to make something that would be pretty but not comfortable to ride at speed. Whew.

Eric
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My Dakar http://www.advrider.com/forums/showthread.php?t=197573
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Old 01-19-2007, 01:06 AM   #4
tintinopsella
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great work mate....wonderfull
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Old 01-19-2007, 08:30 AM   #5
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Awesome job
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Old 01-19-2007, 08:58 AM   #6
514Advrider
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Impressive work!!

I am wondering... What is the exact procedure to mold the body parts? I guess you have to start with a block of solid material that you sculpt to obtain the desired shape, and then you lay the fibre\resin on it? Does this become the final panel, or do you use the resulting part as a pattern for the final piece? Could you explain a bit more on the procedure and material used, maybe you have some extra pictures?
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Old 01-18-2007, 07:47 PM   #7
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I'm in awe of what you've done with your Dakar...hats off. The AT look for the lights actually works--the stock look is not inspiring...what is the net weight loss?
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Old 01-18-2007, 08:13 PM   #8
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Wow, very appealing design. Great looking mods.
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Old 01-18-2007, 08:43 PM   #9
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Very impressive work Eric; congratulations

And anything that can make a BMW GS more Honda TA/AT like has got to be good
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Old 01-18-2007, 09:14 PM   #10
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Old 01-18-2007, 09:22 PM   #11
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Thumb Awesome!

Excellent job!

That's a gorgeous bike. I agree with Cycletroll - you could probably sell some kits to the inmates here. Wish my wife's F650 was that purty!
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Old 01-19-2007, 12:35 AM   #12
ehatcher OP
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Quote:
Originally Posted by flan8tive
what is the net weight loss?
The bike has lost way over 30 pounds, but I am not done yet. It gets a few bits added on, such as a rear rack and possibly a second HID (the ballast and wiring are heavy). On the other hand there are still a few carbon fiber parts to make which will take quite a bit of weight off. I am not sure what the final weight loss number will be, but I would guess around 35 pounds.

Some weight factors are surprising: the parts gained well more than a pound at the paint shop. There was almost a pound of screws and hardware holding the original tail end bodywork together (15oz if I recall right). The twin headlamp assembly actually weighs less than the single BMW unit.

I understand that every 7 - 10 pounds removed is like adding 1 horsepower, but the bike ain't the only thing thats overweight, I could stand to lose 2 - 3 horsepower myself

Eric
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My Dakar http://www.advrider.com/forums/showthread.php?t=197573
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Old 01-19-2007, 12:54 AM   #13
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Keep up the good work.




I think theres a relationship between people who ride and EMS.
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Old 01-19-2007, 02:55 AM   #14
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Man Eric,

When you said your body work might be up for sale because of a fairing you weren't kidding.


What are you doing for the suspension. Are you doing springs and catridge emulators like you mentioned or are you going with new forks?
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Old 01-19-2007, 05:31 AM   #15
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Nice!
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