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Old 02-20-2011, 06:18 AM   #136
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Joined: Feb 2011
Location: Milano, Italy
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Looking forward for new updates!
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Old 02-20-2011, 07:36 AM   #137
Air cooled runnin' mon
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Joined: Jan 2005
Location: NorCal
Oddometer: 7,726
X3300, you've got some mad skills!
Hope if I ever need some welding done I could drop by and have you work your magic.
"Alles hat ein Ende--nur die Wurst, sie hat zwei"

"You only have too much fuel if you're on fire"
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Old 02-20-2011, 08:17 AM   #138
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Location: Brooklyn
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I love how innovative, creative and insanely skilled some people are on this site. This is something I will never do in my life but I am so glad someone is and am happy to be following along!
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Old 03-06-2011, 01:52 PM   #139
x3300 OP
Joined: Mar 2005
Location: San Jose, CA
Oddometer: 170
Tail Light

The UFO rear enduro fender I have came with a simple tail lamp, but it wasn't really suitable for road use; it had a low wattage bulb and no stop lamp. Here's what it looks with the lamp removed.

I liked the idea of LED lamps. They should draw less power and have longer life than a filament bulb. I did a little searching around and found this Truck-lite Super 44 tail lamp and this Puig LED license plate lamp. I liked the big 42 LED tail lamp when I saw it and thought it could give a distinctive look to the back of the bike. The tail lamp is held in place with the rubber grommet shown.

I made up this pattern from card stock for a bracket to hold the license plate, tail lamp and license lamp. The bracket mounts to the fender with a few 5 mm screws.

My custom tool tray will no longer work with my sub-frame, so I cut it up and used the pieces to make the bracket. I bored out the 5" hole for the grommet with this setup.

After I got the big hole bored I laid out the shape then trimmed it down with a metal shear. I punched some holes in the plate mount to lighten it up. Here I've got the pieces clamped together for tack welding.

Here's how it fits to the fender.

I made this top bracket from 1" flat stock. I have it positioned for welding here.

Here's the finished bracket.

And with the lamps installed.

I realized after cutting out the tail lamp holder that the 16 gage aluminum I used will not be strong enough. The photos show how thin it is. Also, to make the look cleaner think I can put the license lamp on the other side of the tail lamp so it shines down without being seen from the rear. This bracket is enough to hold things together for now so I can move on to other things. I'll make up a new bracket later.

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Old 03-26-2011, 08:46 AM   #140
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Joined: Mar 2005
Location: San Jose, CA
Oddometer: 170
Rear Brake

I had thought hooking up the rear brake would be one of the easier things I'd need to do for the new rear end, but as it turned out, I needed to do a fair amount of design and fab to get a working brake.

One thing I wanted to do was to move the actuating arm to be above the pivot so as to be less likely to get damaged when riding through big rocks and such, something that has happened to me before while riding through stream beds. Here's a view of the arm hanging down.

The R100RT final drive I fitted with the monolever arm came with non-symmetric brake shoes and a cam to match. This photo shows some R100GS symmetric shoes and cam on the left and the R100RT shoes and cam on the right.

The cam actuating arm was below the cam pivot so the cam needed to be turned counter-clockwise to apply the brake. As can be seen the cam of the R100RT would not expand the shoes if rotated in a clockwise direction. The top shoe is the self-energizing one in the forward direction. The non-symmetric design applies less force on the top shoe to get more even shoe wear.

I've read that some have modified the cam so that the top and bottom shoes could be switched, but I figured it'd be better to try to use the symmetric setup of the R100GS since it could be actuated by a rotation in either direction and would have more equal shoe actuation.

Here's a closer view of the cams.

I found the R100GS shoes to be 2mm wider than the R100RT shoes, but they fit onto the monolever drive and inside the R100GS hub. Here are the R100GS shoes on the monolever drive.

The shaft of the R100GS was 10mm longer than the monolever shaft.

The shafts were the same diameter, so I figured I could make up a spacer to fill the gap. The outer o-ring seal of the longer GS shaft falls outside the final drive housing as seen here. My plan was to glue the spacer to the final drive with some J-B Weld epoxy to seal the gap between the spacer and final drive.

The R100GS cable was way too short to work as seen here, plus there was no place to fix the rear of the cable housing.

I figured I would need a custom cable housing and inner cable. After some looking around I found that the air cooled Volkswagen Bus clutch cable had a clevis end similar to the R100GS.

Here's the VW Bus inner cable on the right, a disassembled R100GS cable in the center, and a disassembled Harley Sportster clutch cable on the left that I would use for the long housing.

The clevis of the Bus cable was longer than the GS end and would limit how far up the brake pedal would go. I ground a taper on the Bus cable end and countersunk the existing housing end. The mod allowed the Bus cable to retract the same amount as the original GS parts.

After some measuring and checking with the swingarm in the up and down positions I came up with this rear cable mount that I thought would work.

I used this setup to hold the odd shape while machining the back relief.

After some trial fitting I found the original GS front housing end I planned to use didn't support the stiff longitudinally-wound Sportster housing very well. I decided to make up a longer cable end that would weld to the frame. I drilled and tapped two 4mm holes in a 6mm rod coupler to use as a temporary stop.

Here's how the rear mount and housing end fit to the final drive. The square cutout should keep the mount from rotating around the bolt.

With the stiff housing and extreme change in cable position I found I needed to weld the new front housing end to the frame to support the housing properly. I didn't put a slot the in it so I'll need an inner cable that has a removable end, but I can cut a slot later with a thin cutoff wheel if I decide I'd like one.

Here's how the cable looks with the suspension at its extremes. I'll add some kind of wire cable guide to the swingarm to keep the cable in position so it won't hang out were it could get caught on something.

A detail of the rear mount and arm with the cable length properly set.

And a view of the aluminum shaft spacer.

It was a lot more involved than I had originally thought it would be, but I'm very satisfied with the result. I still need to make up the swingarm guide and an adjustable end stop.

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Old 03-26-2011, 09:31 AM   #141
Joined: Nov 2009
Location: Seattle, WA
Oddometer: 5,163
As with everything you've done, this is a very nice mod. This has been on the list for my GS (stock swingarm) for some time and I hope to get to it this spring.
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Old 03-29-2011, 05:56 PM   #142
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Originally Posted by x3300 View Post
You're going to need a bigger tyre than that one...
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Old 04-12-2011, 07:47 PM   #143
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Joined: Mar 2005
Location: San Jose, CA
Oddometer: 170
Rear Wheel

I took the rear wheel apart to do the final build with the proper length spokes. In preparation for powder coating I scrubbed up the rim and hub with a strong detergent and steel wool followed by sand blasting and another detergent scrub and rinse.

The smaller rear rim would just barely fit into the oven I have access to, but I wasn't confident I could get the rim into the oven without jarring the rim and having the loose powder come off, so I decided to use the same setup I used with the front rim to do a partial bake of the rim on the bench to stabilize the coating then I transfered the rim to the oven to do a final bake.

Here's the rim and hub after coating.

I got back in touch with Doug Richardson of The Devon Rim Co. and within a short time 20 spokes 6mm longer than stock arrived. I used the 20 that I had previously ground down shorter for the other side.

There was some interest in my method of building a wheel, so I'll give some more details here. I use a copper based anti-seize to lubricate the stainless spoke threads.

The first spoke is what is commonly called the 'key spoke'. It defines the relationship between the rim and hub. I set the key spoke so that the printing on the rim was at what I thought was the top of the hub.

Then comes the second spoke.

And continue until all ten are in place. I decide on a fixed number of turns, say five, to thread the nipples on so all will be some what equally engaged.

Then I do the other ten to finish one side.

Then I flip the wheel over and do the same on the other side to finish up the lacing part.

At this point all spokes have the same number of threads engaged, but are still really loose. I go around the wheel several times turning each nipple the same amount, say five turns then two turns then one, until the spokes start to get tight.

Once the spokes start getting tight I use a 3mm screw as a depth gage to set all the nipples to have the same engagement.

At this point I'm ready to start to tighten up the spokes to the final tension. I put numbers on the hub to keep track of where I am in a tightening sequence.

I use a torque wrench and a dial indicator to set the spoke tension. The tightening needs to be done such that the hub is centered in the rim without any run-out when the tightening is finished.

My objective is to get all the spokes at equal torque with minimal run-out. The BMW service manual says nipples should be at 5 Nm, but since this wheel has a 14 mm dish, one side needs to be tighter than the other. I set the left to 4.5 Nm and the right to 5.8 Nm. I start with the wrench at a low torque value and work around the wheel in a sequence that I think will get the spokes up to tension while at the same time correcting any run-out. Tightening one spoke effects others around it; crossed spokes will tighten, and parrallel spokes will loosen.

At first I just used this vise-grip to get a rough check of the radial run-out.

I slowly up the torque setting and switch to using the dial indicator as I get closer.

Once the spokes get pretty tight I use a punch to set the spoke heads in the rim.

And pre-stress the spokes to yeild any tight ones.

The BMW spec is 1.0mm run-out, and after some work I was able to get this wheel to a radial run-out of 0.2 mm and an axial run-out of 0.7 mm.

Here's how it looks with a tire mounted.

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Old 04-12-2011, 08:01 PM   #144
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Joined: Jan 2006
Location: Tropical Far East
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Thanks for the write up on wheel rebuilding.

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Old 04-12-2011, 08:20 PM   #145
Joined: Nov 2009
Location: Seattle, WA
Oddometer: 5,163
Would you please train a planet of technical manual editors how it should be done? You write like you're not being paid by the word.

Nicely done (although my bicycle wheels never seemed to go together so easily).

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Old 04-12-2011, 08:38 PM   #146
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Location: Shawangunks
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Dear Sir-

That is awesome. Bike looks great.


Unintentional psychokinesis.
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Old 04-12-2011, 08:40 PM   #147
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Joined: Jan 2004
Location: ... I was born a ramblin' man
Oddometer: 845
Originally Posted by fishkens View Post
Would you please train a planet of technical manual editors how it should be done? You write like you're not being paid by the word.

Nicely done (although my bicycle wheels never seemed to go together so easily).

I think our friend x3300 (geoff) has made many many things look deceptively simple and straightforward in this thread.

His explanations are always clear, concise and a pleasure to read, even if I've got no plans to actually use any of the information he's imparted.

Keep up the good work Geoff ...

The perverse must persevere
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Old 04-12-2011, 11:56 PM   #148
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Joined: Dec 2006
Location: London
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Fantastic work, sir!
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Old 04-13-2011, 02:18 AM   #149
Joined: Mar 2008
Location: Nelson New Zealand
Oddometer: 3,760
That looked so easy I'm tempted to try it myself - I won't - but am tempted
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Old 04-13-2011, 05:09 AM   #150
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Location: Atlanta, GA, USA
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Whoa. Mad. Holy Crap ... that's beautiful.

Fred <|> Need an Airhead Part? .... I May Have It!
'85 BMW R80RT G/Sified <|> '73 BMW R75/5 LWB <|> '94 MZ Silver Star Hack
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