31 BMW 1983 R80ST Remove Front Suspension

Here is the bike after removing the wheels and the handlebars. I’m ready to remove the front forks, steering stem acorn nut, top plate, steering stem pre-load nut, chrome dust cover and the steering stem with the bottom triple clamp attached to it.

Bike After Wheels Removed

Bike After Wheels Removed

Tools

I use a cut-down, 36 mm socket to remove the fork tube top nuts. These are often tightened to 70 Ft-Lbs and the face of the nuts is not very tall, so you need as much contact surface between the socket and the nut as you can get. On most sockets, the edge is tapered so this is what I removed using an abrasive wheel. I checked the socket on a glass plate to ensure the face was flat and square.

Standard 36 mm Socket with Beveled Face

Standard 36 mm Socket with Beveled Face

Grinding Off The Bevel

Grinding Off The Bevel

36 mm Socket with Bevel Ground Off For 100% Contact

36 mm Socket with Bevel Ground Off For 100% Contact

I use the hook spanner included in the bike tool kit to remove the slotted steering bearing pre-load nut.

Bike Tool Kit Includes Hook Spanner For Steering Bearing Pre-Load Nut

Bike Tool Kit Includes Hook Spanner For Steering Bearing Pre-Load Nut

Video

Here is a short video summarizing how I do this work.

VIDEO: 1983 BMW R80ST Charity Build: Remove Front Suspension

Remove Front Forks

The front forks are held in place with the top fork tube bolt and a pinch bolt on the lower triple clamp. There is a bracket under the top fork bolt that secures the top of the headlight bracket.

Top Fork Bolt With Fork Oil Fill Allen Bolt

Top Fork Bolt With Fork Oil Fill Allen Bolt

Bracket That Secures Top Of Headlight Bracket

Bracket That Secures Top Of Headlight Bracket

Fork Tube Allen Pinch Bolt

Fork Tube Allen Pinch Bolt

Before I remove the bolts, I drain the fork oil. There is an Allen bolt in the top of the fork tube nut that I remove. Then I remove the drain bolt to drain the fork oil into a pan.

Removing Fork Top Bolt Oil Fill Plug

Removing Fork Top Bolt Oil Fill Plug

Fork Top Bolt Fill Bolt Hardware Detail

Fork Top Bolt Fill Bolt Hardware Detail

Fork Oil Drain Plug

Fork Oil Drain Plug

Remove Fork Drain Plug

Remove Fork Drain Plug

Draining Fork Oil

Draining Fork Oil

Oil Drain Bolt Hardware Detail

Oil Drain Bolt Hardware Detail

I remove the top fork tube bolt with a 36 mm socket that has the end cut down so it is square. The top fork bolt flats are not very tall and they can be installed at 70 Ft-Lbs of torque so you need full contact on the faces of the nut with the socket so you don’t round of the nut. These fork top nuts are loose so they came out easily. There is a bracket under the nuts that secures the top of the headlight bracket. Then I remove the fork spring.

Removing Fork Top Bolt With Cut-Down 36 mm Socket

Removing Fork Top Bolt With Cut-Down 36 mm Socket

Fork Top Bolt

Fork Top Bolt

Bracket That Secures Top Of Headlight Bracket

Bracket That Secures Top Of Headlight Bracket

Removing Fork Spring

Removing Fork Spring

I remove the triple clamp Allen pinch bolts. I use a large blade screw driver and a plastic mallet and drive the screwdriver blade into the slot on the side of the triple clamp until the forks slide free. I keep my hand on the fork tube as I hammer the screwdriver into the slot so the forks down fall out and slam into the floor.

Fork Tube Pinch Bolt Hardware Detail

Fork Tube Pinch Bolt Hardware Detail

Opening Lower Triple Clamp With Large Blade Screwdriver

Opening Lower Triple Clamp With Large Blade Screwdriver

Sliding Fork Tube Out Of Lower Triple Clamp

Sliding Fork Tube Out Of Lower Triple Clamp

Fork Removed

Fork Removed

I labeled the fork tubes so when I rebuild the forks I will install the fork tube into the same fork slider.

Forks Removed And Fork Tubes Labeled

Forks Removed And Fork Tubes Labeled

I pulled out the fork springs and measured them. They are about 19-11/16 inches or 50 mm long.

Forks Removed From Fork Tubes

Forks Removed From Fork Tubes

Fork Springs Are About 19-11/16 inch (50 mm) Long

Fork Springs Are About 19-11/16 inch (50 mm) Long

Remove Steering Stem

The top fork plate and steering stem are attached to the steering head with a large acorn nut underneath which is a steering head bearing pre-load nut on top of a chrome dust cover. I remove the top acorn nut with a 36 mm socket.

Forks Removed And Ready To Remove Acorn Nut, Top Plate and Steering Stem With Lower Triple Clamp

Forks Removed And Ready To Remove Acorn Nut, Top Plate and Steering Stem With Lower Triple Clamp

Steering Stem And Top Plate Are Secured With 36 mm Acorn Nut

Steering Stem And Top Plate Are Secured With 36 mm Acorn Nut

Using 36 mm Socket To Remove Steering Stem Acorn Nut

Using 36 mm Socket To Remove Steering Stem Acorn Nut

Steering Stem Top Acorn Nut

Steering Stem Top Acorn Nut

Top Fork Plate

Top Fork Plate

The steering head bearing slotted pre-load nut is on top of the chrome dust cover. I use the hook spanner included in the bike tool kit to remove the slotted pre-load nut and then the chrome dust cover.

Steering Stem Top Bearing Slotted Pre-Load Nut

Steering Stem Top Bearing Slotted Pre-Load Nut

Bike Tool Kit Includes Hook Spanner For The Slotted Pre-Load Nut

Bike Tool Kit Includes Hook Spanner For The Slotted Pre-Load Nut

Removing Steering Stem Top Bearing Pre-Load Nut

Removing Steering Stem Top Bearing Pre-Load Nut

The steering head top bearing pre-load nut top side is flat and wide, but the bottom side of the nut is tapered to a narrower face that pushes on the top steering head tapered roller bearing to adjust the pre-load of the steering head bearings.

Steering Stem Top Bearing Pre-Load Nut (Top Face)

Steering Stem Top Bearing Pre-Load Nut (Top Face)

Steering Stem Top Bearing Pre-Load Nut (Bottom Face)

Steering Stem Top Bearing Pre-Load Nut (Bottom Face)

Steering Stem Top Bearing Dust Cap

Steering Stem Top Bearing Dust Cap

Then I use a plastic mallet to drive the steering stem out of the frame. The top inner race will slide up the steering stem releasing the steering stem from the steering head. I will remove the inner bearing races inside the steering head when I replace the steering stem bearings.

Knocking Steering Stem Out Of The Steering Head

Knocking Steering Stem Out Of The Steering Head

Steering Stem With Attached Bottom Triple Clamp Removed From Steering Head

Steering Stem With Attached Bottom Triple Clamp Removed From Steering Head

Steering Head Top Inner Bearing Race

Steering Head Top Inner Bearing Race

Steering Stem Bottom Inner Bearing Race Is Attached To Steering Stem

Steering Stem Bottom Inner Bearing Race Is Attached To Steering Stem

Steering Head Top Outer Bearing Race

Steering Head Top Outer Bearing Race

Steering Stem And Top Plate Components

Steering Stem And Top Plate Components

Here is the bike with the front suspension removed.

Front Suspension Removed

Front Suspension Removed

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