13 BMW 1983 R100RS Remove Carburetors & Air Box

Earlier, when I first got the bike, I rebuilt the carburetors and removed the “Pulse Air” system from the air box. You can read about how I did that here.

The following includes similar information to what’s in the documents above, but here I’ve simplified it to just removing these components.

Remove Carburetors

The carburetors are easy to remove. They are attached to the air box air intake and the engine cylinder intake spigot with straps.

Left Carburetor

Left Carburetor

Air Intake, Air Box Side Straps

Air Intake Air Box Side Straps

Air Intake, Carburetor Side Strap

Air Intake, Carburetor Side Strap

Cylinder Intake Spigot Rubber Bushing

Cylinder Intake Spigot Rubber Bushing

Remove Air Intake From Air Box

Remove Air Intake From Air Box

The air intake rubber bushing attaches to an aluminum bushing in the air box. I push the rubber bushing down the air tube to get it off the air box bushing. Then I remove the air intake from the carburetor.

Slide Air Intake Bushing Down The Intake Tube To Remove

Slide Air Intake Bushing Down The Intake Tube To Remove

Slide Air Intake Bushing Off Air Box

Slide Air Intake Bushing Off Air Box

Air Intake to Air Box, Straps Detail

Air Intake to Air Box, Straps Detail

Air Intake to Carburetor, Strap Detail

Air Intake to Carburetor, Strap Detail

There is a steel bushing inside the air box end of the air intake.

Air Intake Has Bushing on Air Box End

Air Intake Has Bushing on Air Box End

I make the air intakes to make it easier to get the right one on the correct carburetor.

Right Marked On Intake Tunnel

Right Marked On Intake Tunnel

Left Marked On Air Intake

Left Marked On Air Intake

Here are the air intake parts.

Air Intake Parts Detail

Air Intake Parts Detail

Air Intake Details

Air Intake Details

I pull the carburetor off the engine intake bushing and then remove the bushing from the intake spigot. I also remove the fuel lines from the metal tee.

Carburetor Removed

Carburetor Removed

Cylinder Intake Spigot Bushing

Cylinder Intake Spigot Bushing

Cylinder Intake Spigot Strap Detail

Cylinder Intake Spigot Strap Detail

Cylinder Intake Spigot Bushing Detail

Cylinder Intake Spigot Bushing Detail

Cylinder Intake Spigot

Cylinder Intake Spigot

Rag Plugs Engine Intake To Keep Stuff Out

Rag Plugs Engine Intake To Keep Stuff Out

Remove Fuel Line Tee

Remove Fuel Line Tee

Remove Choke & Throttle Cables From Carburetor

The Bing carburetor on the 1983 RS uses a return spring for the choke since the choke lever is attached to the handlebar and uses a flexible braided steel cable. The earlier style choke used solid wire with a lever on the left half of the clam shell cover of the air cleaner.

Rear of Carburetor With Choke (L) and Throttle (R) Cables and Linkages

Rear of Carburetor With Choke (L) and Throttle (R) Cables and Linkages

I remove the return spring so I can easily rotate the choke lever to remove the cable ferrule from the slot in the arm. Then I reattach the return spring.

Choke Lever Mechanism

Choke Lever Mechanism

Remove Choke Cable Return Spring

Remove Choke Cable Return Spring

Remove Choke Cable Ferrule From Lever

Remove Choke Cable Ferrule From Lever

Reattach Choke Return Spring

Reattach Choke Return Spring

Then I loosen the lock nut and unscrew the choke cable adjuster from the top of the carburetor.

Choke Cable Adjuster Hardware Detail

Choke Cable Adjuster Hardware Detail

Remove Choke Cable Adjuster

Remove Choke Cable Adjuster

Unscrew Choke Cable Adjuster

Unscrew Choke Cable Adjuster

Choke Cable Adjuster Detail

Choke Cable Adjuster Detail

The procedure is similar to remove the throttle cable.

Throttle Return Spring

Throttle Return Spring

Remove Throttle Cable Return Spring

Remove Throttle Cable Return Spring

Remove Throttle Cable Ferrule From Lever

Remove Throttle Cable Ferrule From Lever

Reattach Throttle Return Spring

Reattach Throttle Return Spring

Remove Throttle Cable Adjuster

Remove Throttle Cable Adjuster

Throttle Cable Adjuster Detail

Throttle Cable Adjuster Detail

Choke & Throttle Bowden Cable Details

Both the choke and throttle cables on the 1983 model use a Bowden system. There is a single cable that goes to the handlebar that connects to end of a cable splitter mechanism. The other end has the two cables that go to either each choke lever or throttle plate lever on the carburetors. These cables look the same, but the part numbers are printed on the sheath. I put a label on each so I won’t get them confused when it’s time to put things back together.  You can see the internals of the Bowden cable splitter here:

Handlebar Choke Cable-Part# 32 73 1 242 593

Handlebar Choke Cable-Part# 32 73 1 242 593

Carburetor Choke Cables-Part # 32 73 1 242 139

Carburetor Choke Cables-Part # 32 73 1 242 139

Handlebar Throttle Cable-Part# 32 73 1 242 128

Handlebar Throttle Cable-Part# 32 73 1 242 128

Carburetor Throttle Cables-Part# 32 73 1 242 135

Carburetor Throttle Cables-Part# 32 73 1 242 135

NOTE:
Since I am converting this bike to an RT model, I will have to replace the upper handlebar cables for the throttle and choke since they are longer on the RT model,  than the RS model due to the wider RT handlebar.

Here is the carburetor stripped of the fuel line and cables.

Carburetor Removed

Remove Air Box

The yellow pipe inside the bushing in the air box is part of the engine crankcase vent system. I remove the bushing.

Air Box Engine Breather Pipe Inside Aluminum Bushing

Air Box Engine Breather Pipe Inside Aluminum Bushing

Air Box Aluminum Bushing

Air Box Aluminum Bushing

Then I remove the cover with the intake snorkels from the air box and the metal cover clamps.

Open Air Box Cover

Open Air Box Cover

Air Box Snorkel With Snorkels Removed

Air Box Snorkel With Snorkels Removed

Air Cleaner Removed

Air Cleaner Removed

Air Box Cover Clip Mounting Detail

Air Box Cover Clip Mounting Detail

Remove Air Box Cover Clip-Rotate Up and Pull Down

Remove Air Box Cover Clip-Rotate Up and Pull Down

Air Box Cover Clip Removed

Air Box Cover Clip Removed

Remove Intake Tunnels and Crankcase Breather Hoses

Inside the air box are the intake tunnels and the hoses for the engine crankcase breather that feeds crankcase vapor into each carburetor. On the earlier models with the clam shell air filter housing with the cylindrical air filter, there was one breather hose that fed into only the right carburetor air intake tube.

Inside of Air Box-Solenoids Previously Removed

Inside of Air Box-Solenoids Previously Removed

NOTE:
Earlier, I removed the solenoids and the piping to the exhaust passages in the cylinders that is part of what BMW called the “Pulse Air System”. You can read about how I did that here.

The crankcase breather hose comes into a tee fitting inside the air box with a clip to secure it. I slide the clips down the breather hose to remove the hose from the tee and then remove the intake tunnels by pushing them back into the air box.

Air Box Breather Hose Clamp

Air Box Breather Hose Clamp

Remove Air Box Breather Hose From Breather Tee

Remove Air Box Breather Hose From Breather Tee

Pushing Right Intake Tunnel Back Inside Air Box To Remove

Pushing Right Intake Tunnel Back Inside Air Box To Remove

Left Air Box Intake Tunnel Removed

Left Air Box Intake Tunnel Removed

Inside the intake tunnel is a plastic vent pipe that delivers the crankcase vapor into the carburetor intake tube.

Air Box Plastic Vapor Vent Pipe Detail

Air Box Plastic Vapor Vent Pipe Detail

The rubber breather hose presses into the intake tunnel. If you remove the hose, you can pull the plastic vent pipe off the breather hose.

Air Box Breather Hose Connects to Plastic Vent Pipe Inside Air Box Intake Tunnel

Air Box Breather Hose Connects to Plastic Vent Pipe Inside Air Box Intake Tunnel

Left Air Box Intake Tunnel Detail

Left Air Box Intake Tunnel Detail

I mark the intake tunnels so I will easily know which side they go to.

Air Box Intake Tunnels Marked (L-Left, R-Right)

Air Box Intake Tunnels Marked (L-Left, R-Right)

Then I remove the breather hose tee. It fits into the breather hose inside the top engine cover that goes to the crankcase breather valve assembly.

Remove Crankcase Breather Tee

Remove Crankcase Breather Tee

Crankcase Breather Tee Detail

Crankcase Breather Tee Detail

The air box is secured to the top of the transmission with two bolts and one nut. The left bolt and right nut secure the transmission to the engine. The middle bolt used to secure the bottom strap for the older style clam shell halves. I remove the bolts and the nut.

Air Box Mounting Hardware Use Two Bolts and One Nut

Air Box Mounting Hardware Use Two Bolts and One Nut

Remove Middle Bolt

Remove Middle Bolt

Air Box Middle Bolt Detail

Air Box Middle Bolt Detail

Remove Left Air Box Bolt

Remove Left Air Box Bolt

Left Air Box Bolt Detail

Left Air Box Bolt Detail

Right Air Box Nut Hardware Detail

Right Air Box Nut Hardware Detail

The breather hose from the crankcase breather valve has a grommet that the tee fit into. I push the grommet out of the box, slide the air box to the rear and lift it off the top of the transmission.

Push Crankcase Breather Hose Grommet Out of Air Box

Push Crankcase Breather Hose Grommet Out of Air Box

Crankcase Breather Hose Detail

Crankcase Breather Hose Detail

Air Box Removed

Air Box Removed

2 thoughts on “13 BMW 1983 R100RS Remove Carburetors & Air Box

  1. Hello, I am restoring a 1982 R100RS and in the process of removing the airbox i discovered the middle bolt is missing. I noticed oil in the airbox and suspect that it is pulling oil through the bolt hole, or at least i hope so. What is the bolt size please so i can replace it?

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