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Old 05-14-2011, 07:05 PM   #1
Beemerguru OP
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And so it starts....the Original G/SPD assembly

http://gregsgssite.shutterfly.com/

Tomorrow is engine, tranny, and main harness. Not the usual assembly process because the front forks aren't back from reassembly yet. Trying to get this one at least in running condition before Memorial Day.

Body parts are at the painter..new custom Works shocks on order. Wheels off getting polished.

Step at a time.

Nothing like trying to do 3 builds at once..send more scotch
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Old 05-15-2011, 07:57 AM   #2
camgregus
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Greggs drink scotch? We should have our own thread....

Keep it coming...
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Old 11-05-2011, 05:29 PM   #3
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Closer..closer..closer

After almost a year of trial and error, rewiring, reworking, rewelding, rebuilding, re just about everything..it almost ready to go to it's new home
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Old 11-05-2011, 05:53 PM   #4
One Less Harley
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I hope that was your customer's request to do it all in white. besides that very interesting. Like the custom muffler job.
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Old 11-05-2011, 06:08 PM   #5
Houseoffubar
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Very impressive work!
I've been thinking of something similar for my exhaust. Looks very good on this bike!
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Old 11-05-2011, 06:13 PM   #6
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I was something that came together when I looked at the space left back there by extending the swingarm, the increased height from the longer dual shocks, and the desire for the same size panniers..something the normal G/S exhaust system stymied. Then roaming through one of the bike boneyards out here, I saw the flat Ducati muffler and had an "AHA" moment.
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Old 11-05-2011, 06:14 PM   #7
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Quote:
Originally Posted by One Less Harley View Post
I hope that was your customer's request to do it all in white. besides that very interesting. Like the custom muffler job.
Patterned more or less by the factory PD bikes..all had white frames
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Old 11-05-2011, 06:24 PM   #8
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Another thing I noticed about the color..I started going to a gloss black for the powder coating a couple bike's ago instead of the usual 40% standard BMW black..I found the gloss was easier to keep clean than the 40% for some reason. I went with a gloss white instead of a refrigerator white for this one and found all I had to do was spray some WD40 and wipe - and all the greasy fingerprints went away not matter how grimy I got everything.
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Old 11-05-2011, 08:26 PM   #9
bgoodsoil
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Nice! Can you tell us anything about the fairing/headlight?
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Old 11-05-2011, 08:28 PM   #10
Airhead Wrangler
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The way those shocks are mounted on the subframe still has me pretty worried. The lower frame tabs just weren't designed for that. While all the BMW road models of the 70's got by just fine like that, all the PD race bikes mounted the shocks to the main frame. While monolevers got by with a single m10 bolt for the shocks, it was in a clevis arrangement basically doubling its effective shear strength. Those lower M8 subframe bolts are in simple shear and can easily distort the tabs they bolt into. If this thing sees serious off roading and something breaks, I'm betting on those lower subframe bolts and/or the tabs on the main frame. It could start slowly with the holes getting ovalled and then knocking. Also, the lower leg of the subframe on the right side has a big bend in it to go around the stock shock on an r100gs. This side is not nearly as stiff in tension as it's corresponding member on the left and is prone to lengthening if the supension bottoms out and knocks hard. That will distort the subframe as well as the swingarm. Not trying to shit all over your work, and it is nice work, but as an engineer who spends all day fixing failed structural designs, I'm just expressing sincere concern - especially if you're building this for someone other than yourself.

That muffler idea is pretty cool. Good way of saving luggage width without having to go low with it. Nice.
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Airhead Wrangler screwed with this post 11-05-2011 at 08:43 PM
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Old 11-05-2011, 08:33 PM   #11
Toyanvil
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Congratulations That is AWESOME I like the white.
Is the rear tire backward?
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Old 11-06-2011, 06:12 AM   #12
hardwaregrrl
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Quote:
Originally Posted by bgoodsoil View Post
Nice! Can you tell us anything about the fairing/headlight?
http://www.britanniacomposites.com/
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Old 11-07-2011, 10:29 AM   #13
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Actually have some of the same concerns and have another GS subframe being modified to address those issues.

One of those things that when you finally hang it all together for the first time, something looks odd or could have been done better. Kept debating on if it would work or not..normal riding shouldn't be an issue...but that's not the goal here so back to tweaking.

Fortunately,,about 15 bolts and it's all apart and the new one on...couple hours work.




Quote:
Originally Posted by Airhead Wrangler View Post
The way those shocks are mounted on the subframe still has me pretty worried. The lower frame tabs just weren't designed for that. While all the BMW road models of the 70's got by just fine like that, all the PD race bikes mounted the shocks to the main frame. While monolevers got by with a single m10 bolt for the shocks, it was in a clevis arrangement basically doubling its effective shear strength. Those lower M8 subframe bolts are in simple shear and can easily distort the tabs they bolt into. If this thing sees serious off roading and something breaks, I'm betting on those lower subframe bolts and/or the tabs on the main frame. It could start slowly with the holes getting ovalled and then knocking. Also, the lower leg of the subframe on the right side has a big bend in it to go around the stock shock on an r100gs. This side is not nearly as stiff in tension as it's corresponding member on the left and is prone to lengthening if the supension bottoms out and knocks hard. That will distort the subframe as well as the swingarm. Not trying to shit all over your work, and it is nice work, but as an engineer who spends all day fixing failed structural designs, I'm just expressing sincere concern - especially if you're building this for someone other than yourself.

That muffler idea is pretty cool. Good way of saving luggage width without having to go low with it. Nice.
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Old 11-07-2011, 11:31 AM   #14
Airhead Wrangler
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If it were mine, I'd go for this arrangement:



Mount both shocks to the swingarm (not the final drive on one side). Supershaft can tell you how (not) strong a mount that is on the final drive.

Then again, people successfully ran the dakar on BMWs before BMW ever tried. This guy did it on basically the same setup you've got, but I'm not sure what (if any) modifications he made to the frame.



All the other twin shock BMWs that followed that I've seen have used the first arrangement pictured above though or a slight variation thereof.
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Old 11-18-2011, 11:53 AM   #15
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And then you take it apart again!

Nothing like fabrication to test your patience. No matter how much you plan, there is always something you find later that can be done better.

First ride impression: This thing is TALL..but that feeling goes away as soon as you get over 5 mph. Then it handles like a much smaller bike..at 20 mph,fingertip control..smooth and solid. Hands off at 70 and no shakes and tracks straight as an arrow. Suspension needs to be adjusted...little hard in the rear. Brakes are great but the rear needs tweaking.

Got back to the shop and did a walk around a decided to tear the rear apart and rebuild some of the attachment points like this group suggested. Got rid of some curved downtubes and replaced/repositioned the shock mounts with something twice as thick. Reinforced the rear bag mounts and cleaned up some small things.

Off to the powder coater and should all be back together next week for the final shakedown ride.
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