00 BMW 1983 R100RS/RT Assembly From The Frame Up

This document shows how I assemble this bike starting from the frame. I show the order of assembly and frequently link to other documents that provide all the details.  For shorter and less complicated parts of the assembly, I’ll document what I do in this document.

On this project, I’m converting an RS to an RT configuration. That involves mostly changes to the fairing, handlebars and controls.

Before

I started with this.

Bike & Bags When I Got It Home

Bike & Bags When I Got It Home

Right Fairing Detail

Right Fairing Detail

Front Wheel Paint Is In Bad Shape

Front Wheel Paint Was In Bad Shape

Right Side Mid View

Right Side Mid View

Right, Rear Drive Was Painted At Some Point By A Previous Owner

Right, Rear Drive Was Painted At Some Point By A Previous Owner

Right Side Rear View

Right Side Rear View

Rear Wheel Paint Is In Rough Shape

Rear Wheel Paint Is In Rough Shape

Right Cylinder Pulse Air Injection Plumbing

Right Cylinder Pulse Air Injection Plumbing

Gas Tank Neck with Rust

Gas Tank Neck with Rust

Seat Tear

Seat Tear

Original Side Stand Detail and Oil Pan Grunge

Original Side Stand Detail and Oil Pan Grunge

Transmission Bottom with Neutral Switch, Oil Pan and Lots of Grunge

Transmission Bottom with Neutral Switch, Oil Pan and Lots of Grunge

Transmission Throw Out Arm with Grunge

Transmission Throw Out Arm with Grunge

Left Rear Disk Brake Mounting Bracket

Left Rear Disk Brake Mounting Bracket

Left Side Carburetor Leaking

Left Side Carburetor Leaking

And, it mostly fit into these bins (with the exception of the fairing pieces and gas tank) after I completely disassembled it.

An Airhead "Boxer" in Boxes :-) For The Most Part

An Airhead “Boxer” in Boxes 🙂 For The Most Part

Fairing Panels & Gas Tank Removed

Fairing Panels & Gas Tank Removed

Project Index and Videos

I organized all the work by subsystem in the Project Index document.

I made a number of videos to supplement the project documents and posted them on my YouTube channel.

Assemble The Engine Block

On this project, I stripped the engine down to the block. Due to an issue with a low oil pressure light right after I got the bike, I wanted to verify the condition of the main bearings. Here is the order in which I assembled the engine block before I installed the engine block in the frame.

Install The Engine Block In The Frame

I always think of this as the start of creating order out of the chaos of a completely disassembled bike.

Install Push Rod Tubes and Cylinder Studs In Cylinders

I did this work on the bench in preparation for installing the top end.

Install Connecting Rods and Cam Followers

I did this work on the engine block after I installed the engine in the frame

Install The Engine Top End

I like to do this after the engine is in the frame because the engine block is much lighter without the top end installed.

Install Drive Shaft and Swing Arm Bearings

I removed the drive shaft and swing arm bearings since I had the swing arm powder coated.

Replace Steering Head Bearings

I removed the steering head bearings before I had the frame powder coated. Then I installed new bearings.

Install Steering Limit Bolt In Steering Head

The RS and RT fairings are so close fitting that the handlebar movement has to be restricted to keep the ends of the handlebars from contacting the inside of the fairing. I install the bolt and lock nut in the hole in the front of the steering head.

Installed Steering Stop Bolt in The Front Of The Steering Head

Installed Steering Stop Bolt in The Front Of The Steering Head

Steering Stop Bolt Limits Handlebar Movement

Steering Stop Bolt Limits Handlebar Movement

NOTE:
If you use too long a bolt, you will not be able to move the handlebars far enough to push the fork lock tumbler all the way into it’s slot. The stock bolt is an M6 x 22 mm and is part# 07 11 9 904 505.

Replace Main Wiring Harness

I decided to install a new main wiring harness. One end of the main harness terminates inside the headlight shell. I removed the old harness connections and then installed the new harness connections inside the headlight shell.

Lengthen Right Handlebar Switch Wires

The RT handlebars are longer than the RS so the handlebar switch wires are longer for the RT. The left handlebar switch had been replaced previously with one that has the longer RT wires, but I had to lengthen the wires on the right switch.

Replace Ignition System with EME Optical Electronic Ignition System

This bike has the bean can with electronic trigger (Hall effect sensors) and electronic ignition control unit. I decided to replace them with a crankshaft mounted optical trigger with multiple advance curves and electronic ignition control unit from Euro MotoElectrics. I did this work with engine in the frame.

Remove, Refinish & Install Brake Rotors

I had the wheels powder coated so I removed the brake rotors. When I got the wheels back I refinished the rotors and installed them on the wheels.

Replace Wheel Bearings And Adjust Preload

I removed the wheel bearings before having the wheels powder coated. I installed new bearings and adjusted the bearing preload.

Rebuild Forks with Race Tech Cartridge Emulators

I upgraded the forks while rebuilding them by installing cartridge emulators from Race Tech. They should provide better compliance than the damper rods BMW uses.

Install Toaster Tan Fork Top Brace And Install & Align Front Forks

I replaced the thin, flimsy BMW fork top plate with a Toaster Tan fork top brace which is much beefier. This makes the front forks more rigid and improves handling. Installing the fork top brace is part of the process of installing and aligning the front forks. Aligning the forks makes a large difference in compliance as it greatly reduces friction between the fork tubes and the fork lower sliders, aka fork “stiction”.

Install Swing Arm and Rear Drive

The rear drive on this year bike has the 12-sided nuts that secure it to the right side swing arm flange.

Install Sub-Frame

The sub-frame attaches at four points to the frame. This year bike uses recessed Allen bolts at the top so it’s easier to install and remove the battery.

Upper Sub-Frame Mounting Hardware Detail

Upper Sub-Frame Mounting Hardware Detail

Counter-Sunk Allen Bolts Secure Top Of Sub-Frame

Counter-Sunk Allen Bolts Secure Top Of Sub-Frame

The lower sub-frame legs mount to holes in the rear foot peg & muffler brackets on the frame.

Lower Sub-Frame Mounting Hardware Detail

Lower Sub-Frame Mounting Hardware Detail

Lower Sub-Frame Bolt Mounts In Hole In Frame Rear Foot Peg & Muffler Bracket

Lower Sub-Frame Bolt Mounts In Hole In Frame Rear Foot Peg & Muffler Bracket

The grab rail is secured by the front, left sub-frame bolt and an Allen bolt that threads into a hole in the rear of the grab rail from the inside of the sub-frame.

Grab Handle and Rear Allen Bolt Mounting Hardware

Grab Handle and Rear End Allen Bolt Mounting Hardware

Front End of Grab Handle Secured By Sub-Frame Bolt

Front End of Grab Handle Secured By Sub-Frame Bolt

Rear End Of Grab Handle Secured By Allen Bolt Goes In From Inside The Sub-Frame

Rear End Of Grab Handle Secured By Allen Bolt Goes In From Inside The Sub-Frame

All the bolts are torqued to 18 FT-Lbs. The top nuts have a black plastic vanity cover the fit over them.

Torque Sub-Frame Bolts to 18 FT-Lbs

Torque Sub-Frame Bolts to 18 FT-Lbs

Vanity Cover Over Fits Over Top Sub-Frame Nuts

Vanity Cover Over Fits Over Top Sub-Frame Nuts

Sub-Frame Installed

Sub-Frame Installed

Sub-Frame Installed

Sub-Frame Installed

Install Fork and Seat Locks

I replace the special “nail” that secures the fork lock cover as it gets damaged when I remove them.

Install New Gazi Rear Shocks

I install new Gazi rear shocks that I ordered from Tom Cutter at Rubber Chicken Racing Garage.They come with some hardware and hook spanners for changing the rear spring preload to adjust the rear suspension sag. The also have adjustable rebound damping.

New Gazi Shocks Come with Hook Spanners To Adjust Spring Preload To Set The Rear Suspension Sag

New Gazi Shocks Come with Hook Spanners To Adjust Spring Preload To Set The Rear Suspension Sag

The top of the shocks include two large diameter, thin flat washers and a bushing and the bottom of the shock includes a thicker flat washer which is used only on the right rear where the bottom of the shock is secured by the stud in the top of the rear drive.

Gazi Shock With Mounting Hardware Detail

Gazi Shock With Mounting Hardware Detail

Gazi Top Shock Bushing

Gazi Top Shock Bushing

Gazi Thin Flat Washers Go On Both Sides Of Top Shock Bushing

Gazi Thin Flat Washers Go On Both Sides Of Top Shock Bushing

The top shock mounting hardware includes the bolt, a flat washer that fits under the bolt head and a wave washer and nut the fit inside the sub-frame.

Gazi Top Shock Mounting Hardware Detail

Gazi Top Shock Mounting Hardware Detail

The top of the shocks use the same hardware.

Left Top Shock Hardware Detail

Left Top Shock Hardware Detail

Left Top Shock Hardware Detail

Left Top Shock Hardware Detail

But the bottom of the shocks use different hardware on each side. The left side bottom hardware includes a shorter bolt, a flat washer that goes under the bolt head and a thin nut that mounts inside the frame. This allows the rear wheel to clear the lower shock mount when removing it.

Left Bottom Shock Mounting Hardware Detail-Bottom Thin Nut Compared To Nut Used For Top Bolts

Left Bottom Shock Mounting Hardware Detail-Bottom Thin Nut Compared To Nut Used For Top Bolts

Left Rear Shock Mount Uses Shorter Bolt

Left Rear Shock Mount Uses Shorter Bolt

Left Rear Shock Mounts with A Thin Nut For Easier Tire Removal

Left Rear Shock Mounts with A Thin Nut For Easier Tire Removal

The right rear shock mounting hardware includes a large flat washer that fits against the side of the rear drive, the thicker flat washer that came with the Gazi shock, a wave washer and a nut.

Right Rear Shock Mounting Hardware Detail

Right Rear Shock Mounting Hardware Detail

Large Flat Washer Fits On Rear Drive Stud

Large Flat Washer Fits On Right Rear Drive Stud

I install the right shock starting at the bottom by sliding the large flat washer and then the lower shock bushing over the rear drive stud.

Large Flat Washer Goes Against Rear Drive Housing

Large Flat Washer Goes Against Rear Drive Housing

Right Rear Shock Hardware Detail: (Top) Gazi Thick Flat Washer, Wave Washer, Nut

Right Rear Shock Hardware Detail: (Top) Gazi Thick Flat Washer, Wave Washer, Nut

Gazi Thick Washer Goes On Outside of Right, Rear Shock Bushing

Gazi Thick Washer Goes On Outside of Right, Rear Shock Bushing

Then I rotate the shock forward to slide it into the clevis channel at the top of the sub-frame while sliding the two Gazi thin flat washers on either side of the top shock bushing.

Insert Gazi Thin Washers Next To Faces Of Top Shock Bushing

Insert Gazi Thin Washers Next To Faces Of Top Shock Bushing

NOTE:
My clevis channel welded to the top of the sub-frame was bent enough that I couldn’t install the Gazi thin flat washers. I used a shop rag to wrap my channel lock pliers with and used them to bend the inside of the clevis bracket until the bushing and thin flat washers would fit. I found rotating the shock all the way to the front, slipping the Gazi thin flat washers against the shock bushing and then rotating the shock backward to align it with the center hole worked well.

The right shock top bolt mounts in the center of the three holes in the clevis bracket.

Right Side Shock Top Bolt Fits In Center Hole

Right Side Shock Top Bolt Fits In Center Hole

I torque all four shock bolts to 25 FT-Lbs.

Torque Rear Shock Bolts To 25 FT-Lbs

Torque Rear Shock Bolts To 25 FT-Lbs

Rear Shocks Mounted

Rear Shocks Mounted

I’ll adjust the rear shock sag later when I have finished the project.

Install Wheels

I had the wheels powder coated in white. This color was used on the R65LS bikes and I like the contrast with the tires. I think I lightens the look of the bike.

Powder Coated Wheels

Powder Coated Wheels

I start with the rear wheel. I apply a thin coat of wheel bearing grease to the axle. Next, I apply some Moly-60 to the splines of the rear drive unit. These splines engage the splines in the rear wheel.

Light Coat of Wheel Bearing Grease On Axle

Light Coat of Wheel Bearing Grease On Axle

Moly-60 Paste Lubricates Rear Wheel Splines

Moly-60 Paste Lubricates Rear Wheel Splines

Apply Moly-60 To Rear Drive Spines

Apply Moly-60 To Rear Drive Spines

Then I install the rear disk brake plate on the left side of the rear wheel with the casting numbers facing outward. I slide the rear axle through the frame and the hole in the disk brake plate, through the wheel and secure the axle with the large chrome flat washer and nut. I torque the rear nut to 25 FT-Lbs which is the torque I used when I set the wheel bearing preload.

Rear Axle and Brake Plate with Casting Numbers Visible

Rear Axle and Brake Plate with Casting Numbers Visible

Rear Wheel Brake Plate Casting Number Faces Outward

Rear Wheel Brake Plate Casting Number Faces Outward

Rear Axle Left Side Hardware Detail

Rear Axle Left Side Hardware Detail

Torque Axle Nut to 25 FT-Lbs

Torque Axle Nut to 25 FT-Lbs

DANGER:
Over torquing the rear or front axle nuts can cause the wheel bearings to over heat and freeze up. If that happens, you will not have a nice day and will likely add some EMT folks to your list of new acquaintances. :-(.

Rear Wheel Mounted

Rear Wheel Mounted

The front axle hardware includes a spacer that fits on the right side of the axle. Like I did with the rear axle, I put a light smear of wheel bearing grease on the axle.

Front Axle and Mounting Hardware

Front Axle and Mounting Hardware

I check the new front tire for the arrow showing the direction of rotation so I install the wheel with the correct side on the left.

Verify Direction Of Tire Rotation

Verify Direction Of Tire Rotation

I push the axle in from the right side, slide the spacer between the wheel bearing and left fork slower slider and slide the axle all the way through. I install the washer and nut and torque to  25 FT-Lbs.

Sliding The Front Axle Through The Front Wheel Left Side Spacer

Sliding The Front Axle Through The Front Wheel Left Side Spacer

Front Axle Left Side Hardware Detail

Front Axle Left Side Hardware Detail

Torque Front Axle Nut to 25 FT-Lbs

Torque Front Axle Nut to 25 FT-Lbs

Front Wheel Installed

Front Wheel Installed

Here’s the bike with it’s new shoes on. It’s starting to look like a motorcycle again 🙂

Wheels Installed Makes The Bike To Start looking Like A Motorcycle Again

Wheels Installed Makes The Bike To Start looking Like A Motorcycle Again

Install Fairing Brackets

I install the top, middle and bottom fairing brackets. The top bracket attaches to the steering head with two bolts that screw into tapped holes in the front of the steering head. The bolts have a flat a wave washer.

Newly Powder Coated Top Fairing Bracket

Newly Powder Coated Top Fairing Bracket

Top Fairing Bracket Hardware Detail

Top Fairing Bracket Hardware Detail

Top Fairing Bracket Hardware Detail

Top Fairing Bracket Hardware Detail

Top Fairing Bracket Mounted

Top Fairing Bracket Mounted

The middle bracket fits on the lower tube that reinforces the steering head. The cross piece mounts so that the square nut is on the right side and the Allen head bolt, flat washer and wave washer are on the left side. The cross piece is approximately centered between the two cables exiting the inner timing and top engine covers. The cross piece is angled and the ends point to the front as shown below.

Middle Fairing Bracket

Middle Fairing Bracket

Middle Fairing Bracket Hardware Detail

Middle Fairing Bracket Hardware Detail

Clamp Halves Interlock With Tab Of One Bracket in Hole of Other

Clamp Halves Interlock With Tab Of One Bracket in Hole of Other

Middle Fairing Bracket Hardware Detail

Middle Fairing Bracket Clamp Mounting Detail

Middle Fairing Bracket Left Side Hardware Detail

Middle Fairing Bracket Left Side Hardware Detail

Middle Fairing Bracket Fits Between Top Engine Cables

Middle Fairing Bracket Fits Between Top Engine Cables

Middle Fairing Bracket Right Side Hardware Detail

Middle Fairing Bracket Right Side Hardware Detail

Middle Fairing Bracket Installed-Arms Point Forward

Middle Fairing Bracket Installed-Arms Point Forward

The bottom brackets mount on the front engine studs. The brackets are “handed” with the nose pointing to the front. The leg of each bracket is above the engine stud as shown below.

Lower Fairing Brackets Are "Handed"

Lower Fairing Brackets Are “Handed”

Orientation Of Lower Fairing Bracket On Front Engine Mount

Orientation Of Lower Fairing Bracket On Front Engine Mount

Left Lower Faring Bracket Installed

Left Lower Faring Bracket Installed

Install The Headlight Shell

After I install the top fairing bracket on the steering head, I install the headlight shell between the ears of the top fairing bracket.

I start on the left side. I install a flat washer and the rubber gasket on the cylindrical plug in the headlight shell. Then I insert the plug into the hole in the left ear. Then I add the second rubber gasket, the flat washer, the wave washer and the chrome nut.

Headlight Left Side, Inside Hardware Detail

Headlight Left Side, Inside Hardware Detail

Headlight Left Side, Inside Hardware Detail

Headlight Left Side, Inside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Headlight Left Side, Outside Hardware Detail

Left Side Headlight Hardware Installed

Left Side Headlight Hardware Installed

There are two rubber gaskets, a large flat chrome washer and a chrome headed nut on the right side. The right side of the headlight shell slides pass the right bracket ear. Then I insert one of the rubber gaskets between the headlight shell and the ear. I install the other rubber gasket, flat washer and chrome headed bolt.

Headlight Right Side Hardware Detail

Headlight Right Side Hardware Detail

Headlight Right Side, Inside Hardware Detail

Headlight Right Side, Inside Hardware Detail

Headlight Right Side, Outside Hardware Detail

Headlight Right Side, Outside Hardware Detail

Headlight Right Side, Outside Hardware Detail

Headlight Right Side, Outside Hardware Detail

Right Side Headlight Hardware Installed

Right Side Headlight Hardware Installed

Here is the headlight shell installed in the top fairing bracket.

Headlight Installed In Top Fairing Bracket

Headlight Installed In Top Fairing Bracket

Routing The Main Wiring Harness

This shows how I route the main wiring harness and what goes where.

Rebuild Transmission

This is the second transmission I have rebuilt. I wrote five documents showing how I do the work.

Revisions

2020-06-16  Add fairing brackets and headlight shell install.
2020-06-17  Add Routing the Main Wiring Harness.
2020-07-10  Add Rebuild Transmission section.

6 thoughts on “00 BMW 1983 R100RS/RT Assembly From The Frame Up

  1. Brook, I would interested in your comments pertaining to how the rear shocks perform in comparison with some of the other shocks, other than standard equipment, that you have installed in the past.

    • Hi Saunders,

      I have used Gazi shocks on two other bikes: 1975 R75/6 and 1977 R100RS. I like them.

      Best.
      Brook.

  2. Hi. Saunders
    I have a 1981 BMWs R100Rt that I being assembling by part but I have being with this problem trying to assembling my rear wheel. my rear axle can’t go all through it’s get stocked by the brake holder. have tried many different thing to get it done.
    I wish that you could make a video or help me with my situatuion.

    thanks for your time.

    • Hi Fenando,

      It’s possible the tube that sits inside the wheel and that holds the bearing pre-load adjustment wedding bands has shifted and is obstructing the axle. You say you think it’s the “brake holder” on the left that is the problem.
      –> https://flic.kr/p/2j7TnUg

      Can you push the axle through the wheel if you remove the brake holder plate? If so, look at the plate to see if it is damaged in a way that the hole obstructs the axle.

      I hope that helps.

  3. Hi Brook.
    I have a question regarding engine mounting which I think your expertise would speak to, and have the right answers to.

    Airheads seem so A-symetrical, I am unsure how the engine should mount in the frame. I am rebuilding an R60/7 where I have placed the same size spacers (and stand spring mounting hardware) on either side of the engine on the mounting studs in the frame. When regarding the engine from the rear and front it seems the engine is off to one side, LHS. is this to counter the weight of the swing arm/drive and alike, or have I spaced incorrectly? I believe this lack of centring may affect the header mounting and other elements.

    Any advice would be very much appreciated! And thank you for all the truly enlightening articles and instructional to date!!

    • Hi Roman,

      As long as you installed the two shackles on the front engine stud between the engine and the frame and the two spacers on the rear stud between the engine and the frame, then the engine is installed correctly in the frame.

      The drive shaft alignment with the transmission output flange may require the engine to be off center, but I can’t say I ever checked that to know if that’s true.

      As I show in the document on installing the swing arm, 33 BMW 1983 R100RS Install Swing Arm and Rear Drive getting the swing arm centered in the frame is important to reduce wear on the drive shaft.

      I hope that helps.

      Best.
      Brook.

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