- Project Index and Videos
- Rebuild & Assemble The Engine Block
- Install The Engine Block In The Frame
- Install The Engine Top End
- Rebuild Carburetors
- Disassemble, Rebuild & Assemble Transmission
- Rebuild Rear Drive
- Replace Drive Shaft and Swing Arm Bearings
- Replace Wheel Bearings And Adjust Preload
- Refinish, Lace And True Spoked Wheels
- Rebuild Front Forks
- Replace Steering Head Bearings
- Install Toaster Tan Fork Top Brace And Install & Align Front Forks
- Install Electrical System
- Install Handlebars, Instruments and Dash
- Install Fork, Seat and Pannier Locks
- Install Transmission
- Install Swing Arm, Rear Drive, Monoshock
- Install Wheels
- Rebuild Front Brake Caliper
- Install Front Disk Brake System
- Install Rear Drum Brakes
- Install Carburetors, Cables And Air Box
- Shim Oil Filter Canister And Install Filter
- Install Exhaust System
- Install Footpegs
- Install Crash Bars, Side And Center Stand
- Install Seat
- Install Front & Rear Fenders
- Assemble And Install Gas Tank
- First Engine Start
- Install Side Covers & Muffler Heat Shield
- Install Pannier Frame
- Project Complete
This document shows how I reassemble the R80ST starting with the frame and ending with all the parts installed. I document this work in the order I did it.
When I acquired the bike, it was a “project bike” that had been sitting since 1997, or about 24 years before I started work on rebuilding it. Here is what I started with.
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.
Rebuild & Assemble The Engine Block
I rebuilt the engine. Here are links to the work I did. The work is shown in a logical order, but due to parts lead times and other scheduling delays, I didn’t do the work in exactly the order I show below.
- 11 BMW 1983 R80ST Remove Engine Top End & Cam Followers
- 11 BMW 1983 R80ST Remove Engine From Frame
- 11 BMW 1983 R80ST Remove Flywheel
- 11 BMW 1983 R80ST Install Flywheel
- 11 BMW 1983 R80ST Replace Rear Main Seal
- 11 BMW 1983 R80ST Remove, Inspect, Install Oil Pump
- 11 BMW 1983 R80ST Replace Timing Chain, Crankshaft Sprocket & Nose Bearing
- 11 BMW 1983 R80ST Replace Connecting Rod Crankshaft Bearings
- 11 BMW 1983 R80ST Replace Oil Pan & Oil Pump Suction Flange Gaskets
- 12 BMW 1983 R80ST Install Alternator, Diode Board & Electronic Ignition Sensor
- 11 BMW 1983 R80ST Cylinder Measurements & Honing
- 11 BMW 1983 R80ST Replace Push Rod Tubes
Install The Engine Block In The Frame
Install The Engine Top End
Disassemble, Rebuild & Assemble Transmission
Due to delays in getting parts, I had to wait awhile to put the transmission back together. That said, this is when I started rebuilding the transmission.
Rebuild Rear Drive
I decided to rebuild the rear drive as it looked like the seals might be leaking. I had to wait awhile for parts.
Replace Drive Shaft and Swing Arm Bearings
I removed the drive shaft from the swing arm so I can powder coat the swing arm.
Replace Wheel Bearings And Adjust Preload
I replaced the wheel bearings as the bike has sat for almost 25 years and I did not trust the wheel bearings.
Refinish, Lace And True Spoked Wheels
This is the first time I laced and trued spoke wheels. It was an educational experience and took some time to get the wheels trued.
Rebuild Front Forks
I replaced the parts in the forks that are subject to wear and tear.
Replace Steering Head Bearings
BMW uses tapered roller bearings in the steering head rather than ball bearings. This is a legacy from the days they built these bikes to carry sidecars. Unfortunately, the grease in the roller bearings gets pushed away from the contact surface between the roller and the outer race because the roller is not turning all the time. This leads to hardened depressions in the outer race known as brinneling. A good habit to prolong the life of steering head bearings is to move the handlebars lock-to-lock every time you park the bike so the bearing grease gets redistributed.
Install Toaster Tan Fork Top Brace And Install & Align Front Forks
The BMW top fork tube plate is made from a thin piece of steel and is prone to flexing and getting bent. The Toaster Tan top brace is much more stout, eliminates fork stiction due to a bent top plate and improves handling. So I routinely replace the BMW top plate and the acorn nut with one from Toaster Tan, who made a generous donation of these parts in support of my goal to auction this bike for charity with all proceeds going to the Motorcycle Relief Project.
Install Electrical System
Since the bike sat for almost 25 years, I replaced the entire electrical system.
Bench Test Electrical System
Before I install the electrical system, I assembled it on the floor and “bench test”.
Install Headlight Bracket & Headlight Bucket
I install the headlight bracket and the headlight shell next.
Then I install the main wiring harness and attach as many of the electrical components as I can.
Install Rear Sub-Frame
I install the rear sub-frame while I installed the electrical system so I can install the rear turn signals and assemble the tail light. I can’t mount the tail light as the rear fender is still at the painters.
When I’m done I test the electrical system again to be sure everything I can test is working.
Install Handlebars, Instruments and Dash
I assembled the handlebars, controls, instruments (speedometer and tachometer) and the dash. I will wait to install the clutch and throttle cables when I get the transmission and carburetors installed.
Install Fork, Seat and Pannier Locks
The bike came without the key for the front fork lock. So I drilled it out with a 3/8 inch drill while I had the steering stem removed. I picked up a used lock with key from Larry Stonestreet at Stoner’s Beemer Stash.
I didn’t have a key for the seat lock, but a local locksmith was able to make one after he disassembled the lock so he could figure out the height of all five pins. I install it in the hole in the bracket in the back of the rear sub-frame.
I got the left pannier from Larry Stonestreet of Stoner’s Beemer Stash without the locks. A friend donated the right pannier which did have locks in it and no key. Amazing serendipity occurred as the key for the fork lock Larry provided fit the right pannier locks so I could remove them. I use an “L” shaped pick to depress the 6th pin of the lock which secures it in the lock cylinder to I can remove the lock assembly from the lock cylinder. This took a good deal of patience to get all three locks to come out.
I ordered a new set of six locks from MAX BMW so all the locks use the same key.
I usually install the transmission after rebuilding it, but I had to wait for parts so I couldn’t install it right away. Nonetheless this is when I typically install the transmission.
Install Swing Arm, Rear Drive, Monoshock
Since I had to wait to on parts to rebuild the transmission I had to wait to install the transmission. And, I also had to wait for all the parts I needed to rebuild the rear drive. After I install the transmission I install the swing arm, rear drive.and rear monoshock.
Before I install the wheels, I balanced them using the Marc Parnes wheel balancer.
I install the front and rear wheels. The front wheel has an axle. The rear wheel mounts directly to the rear drive with three cone washers and nuts torqued to 75-80 Ft-Lbs.
Rebuild Front Brake Caliper
I rebuilt the front caliper but since I bought a new handlebar control with the master cylinder, I didn’t rebuild the master cylinder.
Install Front Disk Brake System
I install the brake rotor on the front wheel, the brake hose from the master cylinder and the brake pipe to the disk brake caliper and then bled the front brakes.
Install Rear Drum Brakes
The rear brake shoes are installed on the outside of the rear drive. So I had to wait until I finished rebuilding the rear driver before I could install the rear brake shoes. I install the rear brake lever and the rear brake rod and adjust the rear brake light switch so it lights up with only a small movement in the rear brake lever.
Install Carburetors, Cables And Air Box
Here is a link to how I do that work.
Shim Oil Filter Canister And Install Filter
It’s important to set the distance between the oil filter cover and the lip of the oil filter canister at the correct value so the large white O-ring is compressed correctly to seal the oil filter. If this is incorrect, it can cost you an engine. I show how to do this on the 1983 R100RS project. Note that the 1983 R80ST does not have an oil cooler
The R80ST oil filter canister had a depth of about 3.8 mm, so I use two shims and not cover gasket.
You can’t install the oil filter cover until the engine is in the frame as the cover will not clear the lower frame tube.
Install Exhaust System
I had to wait a long time before I got all the new exhaust system parts.
The bike came with the front footpegs but only one rear footpeg. Here are the parts I used for installing the footpegs.
|46 71 1 451 573
|07 11 9 915 558
|HEX NUT – M10-8-ZNS, Footpeg
|46 71 1 451 397
|BUSHING – LEFT, Front Foot Peg Rubber
|46 71 1 451 398
|BUSHING – RIGHT, Front Foot Peg Rubber
|46 71 1 451 575
|SPRING – LEFT, Front Foot Peg
|46 71 1 451 576
|SPRING – RIGHT, Front Foot Peg
|46 71 1 451 473
|FOOTREST, LEFT, Rear
|46 71 1 232 230
|FASTENING ELEMENTS, Rear Foot Peg
|07 11 9 902 912
|HEX BOLT – M10X30-10.9ZNS3, Rear Foot Peg
|07 11 9 904 463
|WAVE WASHER – B10-ZNS3, Rear Foot Peg
The front footpegs are designed to fold up if the bike goes down, so there is a spring that keeps the front footpegs down. The left spring is different from the right spring. I replaced the springs and the footpeg rubbers.
The return spring fits into a hole in the side of the footpeg stem. The other end of the footpeg return spring fits into a gap in the mounting bracket. The long bolt fits through the bracket on the frame, with a flat washer under the bolt head, and slides through the hole in the footpeg stem. On the thread end of the bolt, the footpeg return spring mounts and there is a bushing that fits inside the spring that the bolt goes through. The bolt is secured with a flat washer and lock nut. I tighten the lock nut until the footpeg won’t go back down and then loosen the lock nut a bit until the footpeg will go down by itself.
The right rear footpeg mounts on a hole in the frame, but the left rear footpeg mounts on a bracket on the muffler.
There is a bracket that has a serrated edge that fits into the serrations around the hole on the right side of the frame and attaches to the rear footpeg. The bolt that attaches the footpeg to the bracket is part of the footpeg. The bolt is secured with a wave washer and nut. A bolt with a lock nut secures the rear footpeg bracket to the frame.
I have to mount the rear muffler before I can install the right rear footpeg.
Install Crash Bars, Side And Center Stand
The side stand mounts to a bracket welded onto the right side crash bar, so I install the crash bars before installing the side stand. Then I can put the bike on the side stand to install the center stand. Here is how I do this work
I had the seat reupholstered, as it was in bad shape. Here are some before and after pictures.
The seat on the 1983 R80ST does not use seat hinges. It is secured by a plastic tab that fits inside the frame spine tube at the front and is secured at the rear by the seat lock.
The lock has a plastic tab and that goes on the front side of the lock bracket. The carriage bolt heads face the rear. In order to get the seat locking tab to engage the lock I had to adjust the lock so it was all the way up and I had to adjust the tab on the seat that engages the lock so it was all the way to the rear.
Here is the seat installed.
Install Front & Rear Fenders
I install the fenders before installing the wheels as it is easier to get to the fender mounting hardware when the wheels are not place.
Assemble And Install Gas Tank
This is how I assemble the gas tank and install new fuel lines.
First Engine Start
Here is the procedure for the first engine start and initial 10 mile break-in ride.
This video shows how Joe Broxterman of Speedway Graphics applies the pinstripes. Joe was gracious and donated the pinstripes in support of my charity auction of the bike for the Motorcycle Relief Project.
VIDEO: 1983 BMW R80ST Paint Pinstripes
Install Side Covers & Muffler Heat Shield
I also had to repair some of the tabs on the original left side cover as they were broken. I show how I made the repair.
Install Pannier Frame
The pannier frame is designed to attach to the rear parcel rack. I received the complete pannier frame and parcel rack at no cost from Howard Etkind & Jill McCarley. Thank you so much.
To mount the rear parcel rack, the rear turn signals are removed from the sub-frame and mount in brackets on the rear parcel rack. The parcel rack has a bracket that mounts onto the rear sub-frame grab rail.
The left side and right side panniers mount a bit differently. The left side lower leg mounts on the rear footpeg bolt. The right side lower leg mounts in a hole in the frame. I loosely installed all the mounting hardware before tightening up the nuts and bolts so I can get the pannier frames aligned with their mounting holes.
Here is the installation of the left side pannier rack.
Here is the installation of the right side pannier frame.
Here is the completed pannier and parcel rack frames installed with the panniers mounted.
Here are a couple pictures of the 1983 R80ST after assembling it.