1983 R100RS Rebuild Project Journal

[brook.reams]

Folks,

I'm going to have the heads on this project dual-plugged. Before I sent them to Randy Long who does this work, and more, I did an inspection of the valves to see what I could learn. I documented this work here:

• 11 BMW 1983 R100RS Remove Valves & Inspect Heads

It includes this short video.



Randy does a lot of work on heads, valves and seats and he is who many shops send their heads to. Here is his contact information:

Randy Long
Long's Mechanical Services
74 Risbon Rd
Honey Brook, PA 19344-1754
(610) 286-5870

I hope this is helpful.

Best.
Brook Reams.

[brook.reams]

I'm going to powder coat the swing arm so I need to remove the drive shaft. BMW used two different drive shaft designs on the airheads changing the design in the 1981 model year. This 1983 RS has the second design drive shaft.


Pre-1981 Drive Shaft Components and Swing Arm


Pre-1981 Drive Shaft With Tapered End That Shrink Fits Into Bell Coupling


1981+ Drive Shaft Assembly Components


1981+ Drive Shaft Torsional Shock Absorption Assembly

Cycle Works makes tools to remove the drive shaft. So they have two different tools.

Cycle Works Driveshaft Removal Tool 1955-1980


Pre-1981 Cycle Works Drive Shaft Bell Housing Removal Tool

Here is a link to the description of this tool.

• Cycle Works Driveshaft Coupling Puller, 1955-1980

CCycle Works Driveshaft Spring Compressor Tool 1981+

This the tool used to compress the drive shaft spring so I can remove the snap ring that secures large yoke with the bell coupling from the drive shaft.


1981+ Cycle Works Drive Shaft Removal Tool Components

Here is a link to the tool description.

• Cycle Works Driveshaft Compressor - Post 1980

I documented how I did this work here:

• 33 BMW 1983 R100RS Remove Drive Shaft

And, I made a video showing assembly of the Cycle Works drive shaft spring compressor tool and how I used it to remove the drive shaft.

[Rinty]

Any thoughts on having the swing arm braced, Brook?

[brook.reams]

Any thoughts on having the swing arm braced, Brook?

Hi Rinty,

Well, I have looked at that. The question is "To what purpose?"

The purpose for this build is to be a two-up tour bike, so at the moment, I don't see a real benefit from doing that for the purpose I have in mind for the build.

If I was building a race bike for AHMRA, then I think I would brace it as the stress on the swing arm is much higher and the improvement in rigidity likely would improve cornering at speed.

Anyway, I "pretend" that I spend the budget based on the goals of the build, but I'm as prone as anyone to adding something unique "just because" Keep an eye out for the post about assembling the swing arm to see if bracing shows up.

[Rinty]

I had an RS for about 15 years. I found that the rear end would sashay around a bit with cornering at higher speeds, on certain road surfaces. The braced swing arm settled it down and it felt really planted. I also upgraded the springs front and rear, and upper triple tree.

But I hear you, and if I had another one I would leave it stock, appreciate it for what it is, and just use it as a day bike.

The cost of all the mods I had done were worth it to me, as I enjoyed the bike for many years.

[brook.reams]

I had an RS for about 15 years. I found that the rear end would sashay around a bit with cornering at higher speeds, on certain road surfaces. The braced swing arm settled it down and it felt really planted. I also upgraded the springs front and rear, and upper triple tree.

But I hear you, and if I had another one I would leave it stock, appreciate it for what it is, and just use it as a day bike.

The cost of all the mods I had done were worth it to me, as I enjoyed the bike for many years.

Rinty,

That's a good observation about the "before" and "after" of swing arm bracing. I do plan on installing Race Tech's cartridge emulators and springs on the front end as I have heard good reports about that upgrade. And I plan to install Toaster Tan's top brace which is easier to install on an RS/RT due to not needing to cut down the headlight ears since the RS/RT don't have them.

Thank you for the input on your experience with swing arm bracing. I appreciate it.

Best.
Brook.

[20774]

IIRC Bob Fleischer (aka Snowbum) felt that the swingarm bracing was not necessarily worth the trouble and expense but that work on the front end paid more dividends. Changing the top plate was certainly at the top of his list and a fork brace, if a good one exists without introducing stiction, were two things that would help with handling. He has a section on stiction on this page:

https://bmwmotorcycletech.info/frontforks.htm

[Rinty]

Thank you for the input on your experience with swing arm bracing. I appreciate it.

Best.
Brook.

You're welcome.

I went through a lengthy modification process with mine, and I learned a lot from the experience.

Dave Anderson of Anderwerks, who built it, thought it was the best handling RS he had ever ridden.

I admire your technical skills in upgrading these elegant machines.

[brook.reams]

I'm going to powder coat the swing arm, and the bike has 83,000+ miles on it. So I am removing the swing arm bearings and will replace them.

BMW used two different style bearings on the airhead swing arm: an unsealed 30203 bearing that was changed part way through the 1981 model year (01/1981) to a sealed bearing, FAG 540619. Changes in the swing arm bearing assemble were made at the start of the 1981 model year (09/1980) when the pivot pin was shortened and the dust cap changed to accommodate the 30203 bearing with the shorter pivot pin. Then in January 1981, the sealed bearing was added with it's included dust cap.


FAG Sealed Bearing Disassembled After Removal


Earlier 30203 Bearing Assembly - A Few More Pieces

In the past, I've removed the 30203 bearings using the tool from Cycle Works.


Cycle Works Bearing Puller Kit-Use with 30203 Unsealed Swing Arm Bearings

But I needed a blind bearing puller to remove the inner race from the outer race as it is captive in the sealed bearing design. I found a set of blind bearing pullers for less than $60.00.

• 16 Piece Blind Bearing Puller with Slide Hammer

This kit has a slide hammer and a set of puller legs when more force--that will be required for the outer race extraction--is needed. There are various size expanding sleeves that cover a wide range of bearing diameters, so I bought it.


Less Than $60.00 Blind Bearing Puller Set-Use With Sealed Swing Arm Bearings

I made a collar so I could use the blind puller to remove the outer race from a large flat washer and a 1-1/2 conduit lock nut I found at my ACE Hardware that cost me about $7.00. I used it to remove the outer bearing race after I pulled the inner race out, and it worked nicely. So, if you have a set of blind bearing pullers, or you buy a set like I did, you can remove the outer race by making your own collar.


Collar Rests On Edge Of Tube That Holds The Bearing


Blind Bearing Puller With Jaws Ready To Extract Outer Race


Sealed Bearing Disassembled

Here is a link to the documentation I wrote about how I did this work.

• 33 BMW 1983 R100RS Remove Swing Arm Bearings

I also made a short video and posted it to my YouTube channel.

[brook.reams]

For some reason both tabs that help hold the left side cover on are broken off on the Sub-frame. I fabricated new ones out of some scrap steel lawn edging and had my son weld them on the sub-frame.

If you have to make this repair, here is how I made them.

• 46 BMW 1983 R100RS Repair Sub-Frame Side Cover Tabs

Some pictures follow.


Right Sub-Frame Leg With Original Brackets


Left Sub-Frame Leg With Both Brackets Broken Off


12 mm Socket For Finishing Round End Radius


Use Drift in Vice To Form Radius At End of Bracket


Brackets Ready For Welding


New Tabs Look Just Like The Original


New Tabs Look Just Like The Original

[brook.reams]

Folks,

Previously, I removed the brake calipers and master cylinders when I removed the brake system and you can see how to do that work here:

• 34 BMW 1983 R100RS Remove Brake System

This bike has a front master cylinder that is integrated into the Magura throttle assembly and a rear Brembo master cylinder. All three calipers are Brembo F-08 series with dual 38 mm pistons. I disassembled both master cylinders and inspected them. I repainted and rebuilt the rear master cylinder using a Brembo rebuild kit. Unfortunately, I found the front Magura master cylinder bore and internals were badly rusted and pitted, so I had to replace the front master cylinder rather than rebuild it. Even though I didn't have to rebuild the front master cylinder, I show how you rebuild it and the rear master cylinder in this document.

• 34 BMW 1983 R100RS Disassemble, Inspect & Rebuild Master Cylinders

I also put together two short videos showing the work I did on the front and the rear master cylinders, but I can't post mulitple videos, so here are links to them on my YouTube site.

• VIDEO: Disassemble, Inspect Front Master Cylinder
• VIDEO: Disassemble, Inspect, Rebuild Rear Master Cylinder

I disassembled all three calipers, inspected them and found they were not corroded or pitted so I repainted and rebuilt them using a Brembo caliper rebuild kit. The same kit is used on all three calipers. You can see how I did that work here:

• 34 BMW 1983 R100RS Disassemble, Inspect & Rebuild Brembo Brake Calipers
  

I also put together a video about how I rebuilt the calipers.



1983 R100RS Disassemble, Inspect & Rebuild Brembo Brake Calipers

[brook.reams]

Folks,

I have been delinquent working on this project for a few months. I got distracted with preparations for riding out to the 40th anniversary rally for the R65LS-R80G/S and then, I was lazy when I got back.

For those who need to do this work, I documented how I did it in these write-ups. There is a link in each write-up to a short video summarizing the work.

• 21 BMW 1983 R100RS Remove Clutch
• 11 BMW 1983 R100RS Remove Flywheel & Rear Main Seal
• 11 BMW 1983 R100RS Remove & Inspect Oil Pump

When parts arrive, I'll get the back end of the engine buttoned up and, as is my affliction, I will write-up and film the corresponding documentation.
I hope this is helpful.


Ready To Remove Clutch


Diaphragm Spring



Remove Flywheel


Remove Rear Main Seal


Oil Pump Measurements

Best.
Brook Reams.

[brook.reams]

Folks,

I previously removed the clutch, flywheel and rear main seal so I can replace the crankshaft rear main seal, the flywheel o-ring and the oil pump cover o-ring. You can see how I did that work here:

• 21 BMW 1983 R100RS Remove Clutch
• 11 BMW 1983 R100RS Remove Flywheel & Rear Main Seal

The inside of the bell housing as well as the shelf under the transmission showed oil leaks, so one, or all, of these are the likely culprits.


Grunge Inside the Bell Housing Suggests O-rings and/or Rear Main Seal Leaks


Oil & Grudge On The Shelf Under The Transmission

When I opened up the oil pump to take measurements and make a visual inspection, I decided that I had to replace the oil pump due to a lot of wear and tear to the rotors inside the pump. You can see how I removed and measured the oil pump here:

• 11 BMW 1983 R100RS Remove & Inspect Oil Pump

Scratches On Lobe of Oil Pump Inner Rotor


Grooves on Face of Oil Pump Outer Rotor

When I first got the bike, in debugging a low oil pressure light that came on, I discovered that the oil filter high pressure bypass valve was hanging by a thread. So, unfiltered oil was circulating, but I didn't know for how long. Based on the condition of the oil pump and the scores I found in the rod bearings, I think unfiltered oil circulated for while. Not what I wanted, but I'm glad I took a look at the pump.

You can read about how I did the work here:

• 11 1983 BMW R100RS Install Rear Main Seal, Oil Pump Cover O-ring & Flywheel

And, you can see a short video that summarizes the work here:



Due to what I found with the oil pump, I'm making a detour on the project. I'm going to pull the crankshaft to inspect the main bearings. I suspect I won't like what I find there either, but it makes sense to take a look.

[brook.reams]

Folks,

I am going to replace the timing chain, crankshaft sprocket, crankshaft nose bearing, and the front main seal. I'm also going to pull the crankshaft to inspect the main bearings.

But first, I have to remove the electrical components and wiring inside the front engine cover that includes the diode board, alternator and ignition sensor, aka, the "bean can", aka, the "electronic points". I plan to upgrade the alternator and diode board to a 400 watt system. I also plan on opening the bean can to lube the advance mechanism and replace the Hall effect sensors.

Here is the before and after pictures.


Diode Board, Alternator, Ignition Sensor Are Inside Front Engine Cover


All Gone :-)

You can read about how I did this work here:

• 12 BMW 1983 R100RS Remove Diode Board, Alternator & Electronic Ignition Sensor

And, I shot a video of this work which is a bit long at 20 mins.



My goal in the video is to explain more about what the wiring under the front engine cover does and how it's routed, as well as show how to remove all the components, so that added to the length. I'll try to keep future videos shorter.

I hope this is helpful to anyone thinking of doing this work.

[brook.reams]

Folks,

I remove the inner timing cover to get access to the timing chain, the crankshaft timing sprocket and nose bearing, the timing chain tensioner and the chain rubbing block (aka, slide rail).


Inner Timing Cover Exposed After Electrical Components Removed


Inner Timing Cover Removed

The chain, sprocket, nose bearing, chain tensioner and rubbing block wear and this affects timing. The wear can be great enough that you can hear the timing chain rattle.


What's Under The Inner Timing Cover

You can read about how I do this work here:

• 11 BMW 1983 R100RS Remove Timing Chain, Crankshaft Nose Bearing & Sprocket

I made a short video summarizing the procedure that you will find here.



I will replace the crankshaft sprocket, nose bearing, chain tensioner, rubbing block and the internal components of the oil high pressure relief valve. I will post a separate write-up showing how I do that.

I hope this material is helpful to anyone thinking about doing this work.