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1983 R100RS Rebuild Project Journal

1983 R100RS Project Restart -> R100RS/T Build

Folks,

It's been awhile since I posted anything on this project, but I got distracted with my 1977 R100RS restore and some other things.

So, it's now March 1, 2019 and I'm ready to restart the build on the 1983 RS. But, I changed the direction from restoring it to doing a resto-mod making it into an RT. I have taken to calling this an R100RS/T build project.

I revised my original build plan to reflect this new end state and added a video walk-around of the beginning condition of the bike.



It's a whole lot cleaner than when I brought it home in 2015, but I plan to make a number of modifications to improve it beyond the conversion from an RS to an RT as documented in the updated build plan you can find here.

And, I'll continue to update the project index as I go which you can find here,

So, stay tuned.
 
Tank, Seat, Fairing Removal Completed

Folks,

Due to the blizzard in Denver yesterday, I had time to finish up some documentation on the project so far and post it to my site. The focus has been on the fairing disassembly and a catalog of the fairing mounting hardware and where it goes. I found existing parts fiche aren't very helpful about what fasteners go where.

Here is a link to two new publications.

52 BMW 1983 R100RS Remove Seat and Seat Cowling
46 BMW 1983 R100RS Remove Fairing, Dash, Volt Meter, Clock, Ignition Switch

I included a couple videos, one of which shows details of how all the fairing panels are connected.


Here is what the project looks like so far.

IMG_2666.JPG

And the stack of boxes I use to organize parts, which will grow as I get down to the frame. :)

IMG_2667.JPG

I hope his is helpful.

Best.
Brook Reams.
 
Rear Fender Assembly Removal

I'm making progress on getting to where I can remove the electrical system. I finished taking off, and taking apart, the rear fender assembly that includes the license plate bracket with side reflectors, tail light housing, turn signals and stalk, the cowling tool box and the rear wiring sub-harness.

You can see what I found and how I did the work here.


<a title="Rear Tail Light & Turn Signal Assembly" href="https://www.flickr.com/photos/brook-reams/46467244865/in/album-72157705982603021/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7856/46467244865_a95c6465fd_c.jpg" alt="Rear Tail Light, & Turn Signal Assembly, License Plate Bracket & Rubber Mud Flap" width="800" height="600" /></a>
Rear Tail Light, & Turn Signal Assembly, License Plate Bracket & Rubber Mud Flap

<a title="Tail Light Reflector Wiring Detail" href="https://www.flickr.com/photos/brook-reams/46659172074/in/album-72157705982603021/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7825/46659172074_91e6fe0ba3_c.jpg" alt="Tail Light Reflector Wiring Detail" width="800" height="600" /></a>
Tail Light Reflector Wiring Detail

<a title="Rear Wiring Harness Plug Location" href="https://www.flickr.com/photos/brook-reams/46467242655/in/album-72157705982603021/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm5.staticflickr.com/4918/46467242655_b32ab888f6_c.jpg" alt="Rear Wiring Sub-Harness Plug Location" width="800" height="600" /></a>
Rear Wiring Sub-Harness Plug Location

<a title="Rear Fender Assembly Removed" href="https://www.flickr.com/photos/brook-reams/47382326371/in/album-72157705982603021/" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7876/47382326371_e669317550_c.jpg" alt="Rear Fender Assembly Removed" width="800" height="600" /></a>
Rear Fender Assembly Removed
 
Hey Brook! Thanks for all your patient explanation and documentation. Great job!

A quick thread hijack... I noticed you had a battery tender plugged in on one of the background shots. Do you plug the tender in while the battery is in the bike and just keep it on all winter? Reason I ask is that I had a battery in the Motorsport (you remember... Gonzo's buddy in the van? :)) and had it plugged in to the tender and it leaked from a seam in the bottom. Not much before I caught it but acid did it's damage. Do you remove batteries when trickle charging? Just curious. Thanks! Now back to your thread!
 
Hey Brook! Thanks for all your patient explanation and documentation. Great job!

A quick thread hijack... I noticed you had a battery tender plugged in on one of the background shots. Do you plug the tender in while the battery is in the bike and just keep it on all winter? Reason I ask is that I had a battery in the Motorsport (you remember... Gonzo's buddy in the van? :)) and had it plugged in to the tender and it leaked from a seam in the bottom. Not much before I caught it but acid did it's damage. Do you remove batteries when trickle charging? Just curious. Thanks! Now back to your thread!

Hi Scott,

Good to hear from you again my friend. :)

I trickle charge with them in the frame. Over the past 10 years of doing this, I've not had a cracked battery case.

Now, I've powder coated the battery boxes, frame and swing arms, which is melted plastic. So, should I get an acid leak, I'm curious if the plastic will stand up to it? I suspect it would. But, I'm not eager to run a test. :)

Best.
Brook.
 
1983 BMW R100RS Removing Electrical System

Folks,

After I removed the fairing and rear fender assembly, I removed the electrical system including the main and sub wiring harnesses and the electrical components attached to the frame.

As I did this work, I put together a video tour of the electrical system.


Here are a couple pictures from this document.

<a title="Main Harness Zip Tie Location" href="https://www.flickr.com/photos/brook-reams/47363900562/in/album-72157704124214832/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7878/47363900562_85a54f4fce_c.jpg" alt="Main Harness Zip Tie Location" width="800" height="600" /></a>
Main Harness Zip Tie Location

<a title="Location of Clutch Switch and Front Brake Switch Sub-harness Connectors" href="https://www.flickr.com/photos/brook-reams/40451053283/in/album-72157704124214832/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7927/40451053283_01497e0620_c.jpg" alt="Location of Clutch Switch and Front Brake Switch Sub-harness Connectors" width="800" height="600" /></a>
Location of Clutch Switch and Front Brake Switch Sub-harness Connectors

<a title="Main Harness Leads Near Left Coil" href="https://www.flickr.com/photos/brook-reams/46501352665/in/album-72157704124214832/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7883/46501352665_de525f67c5_c.jpg" alt="Main Harness Leads Near Left Coil" width="800" height="600" /></a>
Main Harness Leads Near Left Coil

<a title="Ignition Module with Connector On Top of Front Brake Manifold" href="https://www.flickr.com/photos/brook-reams/46693407984/in/album-72157704124214832/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7923/46693407984_89fd2dd701_c.jpg" alt="Ignition Module with Connector On Top of Front Brake Manifold" width="800" height="600" /></a>
Ignition Module with Connector On Top of Front Brake Manifold

<a title="Main Wiring Harness Removed" href="https://www.flickr.com/photos/brook-reams/40493488773/in/album-72157704124214832/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://farm8.staticflickr.com/7835/40493488773_e6c0db037b_c.jpg" alt="Main Wiring Harness Removed" width="800" height="600" /></a>
Main Wiring Harness Removed
 
1983 R100RS Removing Brake System

I removed the twin front disk brake system and the rear single disk brake system. The rear brake pedal assembly had a kludge repair to fix the wobbling brake lever. And, the rust was so bad on the rear master cylinder linkage that I couldn't remove the rear brake pedal and had to remove the master cylinder and rear brake pedal together.

You can see how I did this work here:

I shot some short videos of how all the brake system components are connected together, but can't post them here as we are limited to only one video per post. You will find the videos in the above link to the write-up.

This is what the bike looks like at this point. I will remove the disk rotors when I remove the wheels and tires.

<a title="Brake System Removed (Disks Come Off When Wheels Are Removed)" href="https://www.flickr.com/photos/brook-reams/33684034328/in/album-72157704401801812/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/7885/33684034328_28175c88cb_c.jpg" alt="Brake System Removed (Disks Come Off When Wheels Are Removed)" width="800" height="600" /></a>
Brake System Removed (Disks Come Off When Wheels Are Removed)
 
Brook,
Thanks for all your very informative posts.
Although not specific to my project bike (90/6) they help tremendously.
Keep up the great work.
:buds
BR
 
1983 BMW R100RS Remove Front End

Folks,

I finished removing the front end from the bike last week. I wrote up two articles showing how I do this work that you can find here:

Before doing this work, I also removed the center stand as I put the bike on my portable motorcycle lift to make it easier to remove the wheels and forks.

In summary, these articles show how to remove:

  • Handlebar controls,
  • Handlebar,
  • Instruments & bracket
  • Steering damper,
  • Front fender,
  • Front wheel,
  • front fender brace,
  • Front forks
  • Steering stem & fork top plate
I started here:

<a title="Brake System Removed (Disks Come Off When Wheels Are Removed)" href="https://www.flickr.com/photos/brook-reams/33684034328/in/album-72157704401801812/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/7885/33684034328_28175c88cb_c.jpg" alt="Ready To Remove the Front End" width="800" height="600" /></a>
Ready To Remove the Front End

and ended up here.

<a title="Front End Removed" href="https://www.flickr.com/photos/brook-reams/47582945611/in/album-72157679817744008/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/7859/47582945611_537f9169a2_c.jpg" alt="Front End Removed" width="800" height="600" /></a>
Front End Removed

Next on the list of projects is removing the rear wheel, rear drive, swing arm, rear sub-frame and seat lock mechanism.
 
1983 R100RS Remove Rear End

Folks,

I've completed the disassembly of the rear end of this bike. Previously I removed the rear fender, tail light and turn signal assemblies. Now, I completed removal of the rear wheel, rear drive and swing arm. You can read about that work here:

Next up will be removal of the transmission including the clutch throw-out rod mechanism and the foot shifter mechanism.

Here is where I started.

<a title="Front End Removed" href="https://www.flickr.com/photos/brook-reams/47582945611/in/album-72157679817744008/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/7859/47582945611_537f9169a2_c.jpg" alt="Front End Removed & Ready To Start On The Rear End" width="800" height="600" /></a>
Front End Removed & Ready To Start On The Rear End

And here is what the bike looks like now.

<a title="Bike After Sub-frame Removed" href="https://www.flickr.com/photos/brook-reams/33712719718/in/album-72157679833426098/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/7912/33712719718_b7deb43d99_c.jpg" alt="Bike After Rear End Removed" width="800" height="600" /></a>
Bike After Rear End Removed

Next up is removing the transmission, clutch throw-out arm and rod, and the foot shifter.
 
your rebuild is impressive,any tips as to how you got your carbs so shinny
getting ready to rebuild a set of my own
thanks
 
How I Refurbish Carbs

your rebuild is impressive,any tips as to how you got your carbs so shinny
getting ready to rebuild a set of my own
thanks

Hi Tinkerer,

Sure, here is a link that shows how I refurbish them and get them to look new. The rebuild covers the smaller 64/32 carb, but the refinishing technique is the same.

I also posted a document on rebuilding these larger 94/40 carbs which maybe of interest to you.

I hope this helps.

Best.
Brook.
 
1983 R100RS Remove Carbs, Air Box, Exhaust, Transmission & Engine Top End

I've finished removing more on the bike and have posted documents about how I did the work here.

13 BMW 1983 R100RS Remove Carburetors & Air Box
18 BMW 1983 R100RS Remove Exhaust System
23 BMW 1983 R100RS Remove Transmission
11 BMW 1983 R100RS Remove Engine Top End

I also made a short video showing how to remove the top end.

VIDEO: 1983 BMW R100RS Remove Engine Top End

At this point, disassembly is almost done, and the real work begins; repair, rebuild and refinishing all the components of the bike.

Best.
Brook Reams.
 
Last edited:
1983 R100RS How To Disassemble Down To The Frame

I got the engine out of the frame yesterday so I'm finished with disassembly (small cheer can be heard).

I wrote a document that covers the complete disassembly procedure in the order I did the work.

This may be helpful to you if you are doing a frame off rebuild/restore, or you need to know how to remove various subsystems. The bike, with the exception of the body work, fits into a reasonably small pile of boxes ... sort of a boxed, boxer if you will :). :dance

<a title="Engine Removed" href="https://www.flickr.com/photos/brook-reams/40705886483/in/dateposted-public/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/65535/40705886483_1260c7ebec_c.jpg" alt="Engine Removed" width="800" height="600" /></a>
Engine Removed

<a title="Frame" href="https://www.flickr.com/photos/brook-reams/47672219881/in/dateposted-public/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/65535/47672219881_b9d4e8e42d_c.jpg" alt="Naked Frame" width="800" height="600" /></a>
Naked Frame[/caption]

<a title="A "Boxer" Airhead in Boxes :)" href="https://www.flickr.com/photos/brook-reams/32729465607/in/dateposted-public/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/65535/32729465607_9d75c51042_c.jpg" alt="A Boxed "Boxer" :)" width="800" height="600" /></a>
A Boxed "Boxer" :)


Onward. But first I'm giving "Grover", the 1973 R75/5 some well deserved attention.


Best.
Brook Reams.
 
1983 R100RS Project: How To Remove Push Rod Tubes & Cylinder Studs

When BMW introduced the Nikasil cylinders in the US in the 1981 model year, they came with the 8.2:1 low compression pistons to help meet EPA requirements. So, my 1983 R100RS has low compression pistons. But, in Europe, BMW provided 9.5:1 pistons and rings for use in the Nikasil cylinders and they are still available.

The higher compression makes a useful difference in torque and horsepower:

  • The 8.2:1 compression pistons produce 53-Ft-Lb and the 9.5:1 compression produces 56 Ft-Lb and, or about +5% for the higher compression.
  • The 8.2:1 compression pistons produce 66 Hp and the 9.5:1 compression produces 70 Hp and or about +6% for the higher compression.

I intend to use this bike for two up touring and it has over 80,000 miles on it. So I am going to install 9.5:1 pistons sized for the "B" sized cylinders I have (part# 11 25 1 337 175) to get a useful boost in torque and horsepower.

<a title="New 9.5:1 Piston Kit" href="https://www.flickr.com/photos/brook-reams/48034259243/in/album-72157709011338913/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/65535/48034259243_a5ae1da911_c.jpg" alt="New 9.5:1 Piston Kit For "B" Size Cylinder" width="800" height="600" /></a>
New 9.5:1 "B" Size Piston Kit For "B" Size Cylinder

<a title="New 9.5:1 Piston Kit" href="https://www.flickr.com/photos/brook-reams/48034259168/in/album-72157709011338913/" target="_blank" rel="noopener" data-flickr-embed="true"><img src="https://live.staticflickr.com/65535/48034259168_66aed54cfc_c.jpg" alt="New 9.5:1 Piston Kit Contents" width="800" height="600" /></a>
New Piston Kit Contents-"B" Size, 9.5:1 Piston (93.97 mm)

Here is the link to the write-up of the procedure.


And here is a link to a short video I made of the procedure. It shows the "Risky" way to remove the push rod tubes--and the unintended consequence--and a "Safer" way to do it.

 
Brook -

In the video you mention some dimensional difference between the cylinder sealing surface and the edge of the pushrod tube collar. According to Oak, there wasn't any difference there...the collar was exactly equal to the level of the sealing surface. I drew up a crude image of that here:

https://forums.bmwmoa.org/showthread.php?53365-Help-with-the-top-end!&p=682593&viewfull=1#post682593

Obviously, there's a happy medium there. If the collar is too tight or sticks past the sealing surface, then too much pressure is applied to the seals. If the collar is too far away or lower than the sealing surface, there's the danger of not having sufficient pressure on the seals to keep them oil free.
 
Brook -

In the video you mention some dimensional difference between the cylinder sealing surface and the edge of the pushrod tube collar. According to Oak, there wasn't any difference there...the collar was exactly equal to the level of the sealing surface. I drew up a crude image of that here:

https://forums.bmwmoa.org/showthread.php?53365-Help-with-the-top-end!&p=682593&viewfull=1#post682593

Obviously, there's a happy medium there. If the collar is too tight or sticks past the sealing surface, then too much pressure is applied to the seals. If the collar is too far away or lower than the sealing surface, there's the danger of not having sufficient pressure on the seals to keep them oil free.

Hi Kurt,

Indeed, Oak's recommendation is different. I believe the difference between what Oak recommended and what Tom recommends has to do with which cylinder you have; the older ALFIN cylinders with the smaller diameter push rod tubes in the smaller bore blocks, or the later ALFIN or Nikasil cylinders with the larger diameter tubes in the 99 mm bore blocks. Those changes in the cylinder design and engine block changed the angles of the tubes and that caused changes in the push rod tube seals IIRC (different part numbers for these). Tom's recommendation applies to the later design, which is what I have, so I plan to follow his suggestion.

As a reference point, I used the 1.75 mm depth on my 1977 RS with Nikasil cylinders (yes, those weren't the original cylinders) and after 2 years and 10,000 miles, I haven't seen any leaks.

Best.
Brook.
 
1983 R100RS Project: Remove Connecting Rods

I'm going to have the Nikasil cylinders on this bike replated and honed to match the new 9.5:1 pistons I'm going to install in this build. I've learned from a well versed airhead mechanic, Tom Cutter, at Rubber Chicken Racing Garage, that the connecting rods are subject to deformation over time such that the distance between the hole centers of the big end and little end of the rod becomes a bit longer than when new. It's worth having them checked and the flat of the connecting rod cap machined to achieve the design distance between the hole centers. This is not very expensive and ought to reduce wear and tear on the wrist pin and crank shaft throw.

Removing the connecting rods is straight forward once you have the top end removed. This link shows how to remove the top end:

And this one shows how I removed the connecting rods.

Here is a short video I made showing the tools and the procedure.

 
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