31 BMW 1977 R100RS Install Steering Stem, Front Forks, Telefix Fork Brace and Toaster Tan Top Brace

Before I started this work I had completely removed all the front end components so I can have the frame powder coated, and I replaced the steering head bearings and rebuilt the front forks. You can read about this work here.

I replaced the stock top brace and steering stem nut with components from Toaster Tan. The stock top brace is not very stout and is easily bent causing the forks to not stay parallel in the X and Y planes. The Toaster Tan top plate is machined out of an aluminum billet, is thicker, and has a longer sleeve for the fork tubes to sit in.

Toaster Tan Top Brace Parts and "Acorn" Nut

Toaster Tan Top Brace, Bolt Kit, and Steering Stem “Acorn” Nut

Toaster Tan Top Clamp Parts and Steering Stem Nut

Toaster Tan Top Clamp, Sleeves, and Steering Stem “Acorn” Nut

The Toaster Tan steering stem nut has a longer skirt so there is more contact between the nut and the top plate. This combination creates a very stiff top clamp with much more resistance to flexing and permanent deformation so the front end behaves more predictably and fork stiction is minimized.  All good things IMHO. 🙂

Parts

I used the following parts in this work.

Part # Description                        Qty
31 42 1 232 361  STEERING DAMPER 1
31 42 1 235 615  RUBBER GROMMET 2
31 42 1 232 241  BUSH 2
31 42 1 232 242  BUSH 2
31 42 1 235 620  RUBBER GROMMET 2
31 42 1 232 243  CAP 4
07 11 9 903 791  WASHER – 6,4 2
07 11 9 904 115  WAVE WASHER 4
TT-101 Toaster Tan Top Clamp 1
TT-301D Toaster Tan Steering Stem Nut w/ Damper Hole 1
Install Bolts Toaster Tan Top Clamp Mounting Bolts SS 1
07 11 9 985 070 TAPERED ROLLER BEARING – 28X52X16 2
31 42 1 234 509 RING 1

A number of instrument bracket parts needed replacement:

  • Large and small rubber bushings (part# 31 42 1 235 615 and 31 42 1 235 620)
  • the chrome covers and lock washers on the large rubber bushings (part# 31 42 1 232 243)
  • the steel bushings in the small rubber bushings (part# 31 42 1 232 241)
  • the steel bushings in the large rubber bushings (part# 31 42 1 232 242) were found at ACE Hardware for pennies while the BMW part was about $11.00.
ACE Hardware Steel Bushings

ACE Hardware Steel Bushings

I also replace the steering damper and the steering head bearings and bottom dust cap.

Tools

Cycle Works Fork Alignment Measurement Tool (Source: Cycle Works)

Cycle Works Fork Alignment Measurement Tool (Source: Cycle Works)

  • I used a vernier caliper to check the height of the fork tubes from the lower clamp.
  • And I used typical shop tools.

Add Roll Pins to Lower Triple Clamp for Fork Gaiters

I cleaned and polished the lower triple clamp on the steering stem.

Cleaned and Polished Triple Clamp on Steering Stem

Cleaned and Polished Triple Clamp

The 1977 R100RS did not come with fork gaiters but used a cap to protect the fork seals. This design leaves the fork tubes unprotected from rocks that can nick the tubes and that causes seal failure. So I’m going to put the fork gaiters on the forks. The top of the gaiters have a hole that fits into a role pin providing a passage for the air to move in and out of the gaiter as the forks move up and down. I found some at my ACE Hardware that will work (the hole is sized for a 5 mm roll pin) and install them in bottom of the lower triple clamp.

Metric Roll Pin (5 mm) for Fork Gator

Metric Roll Pin (5 mm) for Fork Gator

Fork Gator Roll Pin Installed

Fork Gator Roll Pin Installed

Install Steering Stem in Steering Head

The procedure for the 1977 R100RS is the same as for the 1973 R75/6 and you can read about how I do it here.

These are the parts for installing the steering stem.

Steering Stem Assembly Top Parts

Steering Stem Assembly Top Parts

I generously greased the upper and lower tapered roller bearings with NLG red grease when I installed the steering stem.

NLG Red Grease

NLG Red Grease

Bottom Steering Head Bearing Packed with Grease

Bottom Steering Head Bearing Packed with Grease

Bottom Steering Head Bearing Packed with Grease

Bottom Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

Top Steering Head Bearing Packed with Grease

The orientation of the top chrome dust cover, steering stem nut and steering stem acorn nut are shown below. The steering stem nut has a tapered end and that end goes against the chrome cover. Although this seems backwards, it ensures the nut presses on the inner bearing race to preload the tapered roller bearing.

Chrome Cover Fits on Top of Top Tapered Roller Bearing

Chrome Cover Fits on Top of Top Tapered Roller Bearing

Steering Stem Nut Has Tapered End That Goes On Top of Chrome Cover

Steering Stem Nut Has Tapered End That Goes On Top of Chrome Cover

Steering Head Top Parts Order

Steering Head Top Parts Order

Tapered Side of Top Steering Stem Nut

Tapered Side of Top Steering Stem Nut

Steering Stem Nut Orientation on Top Steering Stem Bearing

Steering Stem Nut Orientation on Top Steering Stem Bearing

Install Steering Stop Limiting Bolt, Washer and Nut

Due to the narrow width of the aerodynamic RS fairing, BMW limited the amount of handlebar rotation by installing an M6 bolt in the steering head (part# . I added a couple extra washers under the bolt head and nut on mine to shave a little more off the maximum left and right movement. When I rode the bike before taking it apart, I was unable to get the bars to stop scrapping the inside of the fairing.

Steering Stop Limit Bolt with Washer and Nut

Steering Stop Limit Bolt with Washer and Nut

Steering Stop Limit Bolt Reduces Maximum Handlebar Movement To Accommodate Narrow RS Fairing

Steering Stop Limit Bolt Reduces Maximum Handlebar Movement To Accommodate Narrow RS Fairing

 

Install Fork Tubes and Align Them

The procedure for the 1977 R100RS is the same as for the 1973 R75/5 and you can read about how I do it here.

Please read that material before continuing. I’ll point out the differences in what I did on the R100RS but I won’t repeat the procedure.

Setting Fork Tube Height

I align the marks I made on the fork tubes to identify the high side of each tube so both lines face forward when I install the tubes in the lower triple clamp. The stated distance is 160 mm from the top of the fork tube to the bottom edge of the lower triple clamp.

Measuring Fork Tube Height From Bottom Triple Clamp

Measuring Fork Tube Height From Bottom Triple Clamp

Measuring Fork Tube Height From Bottom Triple Clamp

Measuring Fork Tube Height From Bottom Triple Clamp

However, when I installed the Toaster Tan top brace as described later, I had to adjust the fork tube height to 161 mm to allow the sleeves in the top clamp to be at the right depth.

Adjusted Fork Tube Height to Meet Toaster Tan Sleeve Depth Height

Adjusted Fork Tube Height to Meet Toaster Tan Sleeve Depth Height

Checking X and Y Axis Alignment

This time I use the Cycle Works fork alignment tool with the dial indicator to check the alignment in the X-axis. I find the forks are in alignment in both the X and Y axis so I didn’t have to adjust them as I did on the R75/5.

Measuring Fork Tube Separation

I check the alignment as I add parts to the forks.

  • After I install the tubes in the lower triple clamp and tighten the Allan head screws.
  • After I tighten the Toaster Tan steering stem “acorn” nut finger tight.
  • After I tighten the Toaster Tan pinch bolts with the sleeves installed.

At each step the forks stayed in alignment.

Here are two short videos showing how I checked the fork tube alignment  in the X and Y planes.

Install Toaster Tan Top Brace

The top brace comes with two sleeves that go around the top of the fork tubes.

Toaster Tan Top Clamp, Sleeves and Steering Stem Nut

Toaster Tan Top Clamp, Sleeves and Steering Stem Nut

It fit well on the steering stem and the fork tubes.

Toaster Tan Top Clamp Installed on Steering Stem and Fork Tubes

Toaster Tan Top Clamp Installed on Steering Stem and Fork Tubes

The center “acorn” nut fit tightly on the steering stem. I snug it down.

Toaster Tan Steering Stem Nut - Nice Tight Fit in Top Clamp

Toaster Tan Steering Stem Nut – Nice Tight Fit in Top Clamp

The top brace is above the top of the fork tubes.

Toaster Tan Top Clamp with Fork Tube Inserted

Toaster Tan Top Clamp with Fork Tube Inserted

Then I insert the two rings that fit on top of the fork tubes.

Toaster Tan Fork Tube Ring Installed Above Fork Tube

Toaster Tan Fork Tube Ring Installed Above Fork Tube

The two rings are supposed to be 0.7 mm above the top of the plate when resting on top of the fork tubes. Mine were recessed with the fork tubes at 160 mm so I increased the fork tube height to 161 mm to get rings at the 0.7 mm height.

Measuring Toaster Tan Fork Tube Spacer Height Above Top Clamp

Measuring Toaster Tan Fork Tube Spacer Height Above Top Clamp

Measuring Toaster Tan Fork Tube Spacer Height Above Top Clamp (0.7 mm)

Measuring Toaster Tan Fork Tube Spacer Height Above Top Clamp (0.7 mm)

Temporarily Install the Fork Sliders

The following hardware is used to attach the fork slider to the damper rod.

Fork Lower to Damper Rod Mounting Hardware

Fork Slider to Damper Rod Mounting Hardware

I use a bit of grease to install the small diameter aluminum washer from the fork rebuild kit on the threaded end of the damper rods. Then I install the fork sliders on the fork tubes carefully so I don’t damage the fork seals.

Dap of Grease To Hold Small Aluminum Washer On Bottom of Damper Rod

Dap of Grease To Hold Small Aluminum Washer On Bottom of Damper Rod

Easing Fork Slider on Fork Tube

Easing Fork Slider on Fork Tube

I use a small philips head screw driver to align the damper rod with hole in the fork slider cap nut and push up on the slider until enough thread shows to install the wave washer and nut on the end of the damper rod.

Fishing Damper Rod Through Fork Slider

Fishing Damper Rod Through Fork Slider

I put a bit of anti-seize on the damper rod threads then install the wave washer and nut on the threaded damper rod finger tight.

Blue Locktite on Fork Damper Threads

Anti-seize on Fork Damper Threads

Damper Rod Bottom Nut & Washer

Damper Rod Bottom Nut & Washer

Here are the sliders installed on the forks.

Fork Lowers Installed

Fork Sliders Installed

I insert the axle in the fork sliders to ensure they easily slides in the holes and isn’t binding. Here is a short video of how easily the axle should slide between the fork sliders.

Then I grab the axle and pull the fork sliders all the way to the top and drop them to estimate the time it takes for the lower to fall from being fully compressed.

Use Axle To Pull Up Lowers to Test Stiction

Use Axle To Pull Up Lowers to Test Stiction

Install Stock Fork-Fender Brace and Fork Sliders

The stock fork-fender brace has an edge with four holes which is the edge that faces forward. It mounts on the fork sliders using four Allan bolts, nylock nuts and wave washers.

Stock Fork-Fender Brace-The 4 Hole Edge Faces Forward

Stock Fork-Fender Brace-The 4 Hole Edge Faces Forward

Stock Fork-Fender Brace & Brake Hose Mounting Hardware For One Fork Slider

Stock Fork-Fender Brace & Brake Hose Mounting Hardware For One Fork Slider

It’s hard to install the stock fork-fender brace with the sliders on the fork tubes, so I remove the fork sliders and install the stock fork-fender brace with the bolts loose and then slide both fork sliders on the forks tubes being careful to not damage the fork seals. I I secure the Allan bolts with a wave washer and  nylock nut.

Stock Fork-Fender Brace Uses Nylock Nut & Wave Washer

Stock Fork-Fender Brace Uses Nylock Nut & Wave Washer

The rear Allan bolts also secure the brake line brackets. The bracket fits on the outside of the  fork-fender brace next to the tire, not between the brace and fork slider.

Install Stock Fork-Fender Brace Loosely on Lowers

Install Stock Fork-Fender Brace Loosely on Lowers

Disk Brake Hose Bracket Goes Next to Tire on Outside of Stock Fork-Fender Brace

Disk Brake Hose Bracket Goes Next to Tire on Outside of Stock Fork-Fender Brace

Install Stock Fork-Fender Brace Loosely on Lowers

Install Stock Fork-Fender Brace Loosely on Lowers

Install Stock Fork-Fender Brace Loosely on Fork Sliders

Install Stock Fork-Fender Brace Loosely on Fork Sliders

Before I install the fork sliders with the loosely attached stock fork-fender brace, I install the rubber fork gaiters on the fork tubes. The top of the gaiter has a hole that fits over the roll pin in the bottom of the lower triple clamp. I secure the top of the gaiters using the hose clamp on the boss on the lower triple clamp but I don’t install the bottom on the fork sliders so I can check for stiction as I assemble the stock fork-fender brace and Telefix fork brace.

With the bolts loose, I install the fork sliders on the fork tubes and tighten the nut on the end of the damper rod. Then I use a socket in vice grips and an Allan key to tighten the nuts as described in the 1973 R75/5 write-up.

13 mm Socket in Vice Grip Pliers

13 mm Socket in Vice Grip Pliers (From 1973 R75/5 Procedure)

Tightening Damper Rod Nut (From 1973 R75/5 Procedure)

Tightening Damper Rod Nut (From 1973 R75/5 Procedure)

I want to test for any increase in fork stiction as I assemble the stock fork-fender brace and the Telefix fork brace. I put a little WD-40 on the fork tubes and wipe it up and down the tube to minimize fork seal friction. Then I pull the forks all the way to the top of their travel and drop them and note how long they take to drop to the bottom. This should take a second or less if the fork tubes have been aligned in the X and Y planes as described above.

Here is the initial test with the fork sliders installed and the stock fork-fender brace attached but the bolts not tightened yet.

NOTE:
Due to the sequence of events I installed the brake calipers prior to making videos of these tests. You can do these tests without the calipers but the fork sliders may slide a bit slower than in my tests. I cover installation of the disk brakes in this write-up.

I tighten the bolts one at time and torque them to 16 FT-Lbs. I grab the axle and pull the fork sliders to the top and drop them to see if the stiction increased. On the last bolt, left rear, the stiction went up. I loosened that bolt and can see a narrow gap between the brace and the inside flat of the fork slider.

Thin Washer Needed To Remove Gap Between Stock Fork-Fender Brace and Fork Slider

Thin Washer Needed To Remove Gap Between Stock Fork-Fender Brace and Fork Slider

I use a thin washer and insert it into the gap and then tighten all four Allan bolts one at a time testing the stiction after each one. I don’t detect any increased fork stiction.

Here is the test with the stock fork-fender brace Allan bolts tightened.

Install Telefix Fork Brace

NOTE:
Before installing the Telefix fork brace, you have to install the front fender due to limited clearance between the top of the fender and the bottom of the fork brace. You can see how to that here:

[link to front fender install]

After I removed the Telefix fork brace, I cleaned it up. Here are the parts.

Telefix Fork Brace Components

Telefix Fork Brace Components

I found instructions for installing the Telefix fork brace on-line and down loaded them. Here they are.

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

Telefix Instructions

If you turn the brace upside down you can see numbers on the outer and inner fork tube clamps. The numbers on each part should match on each side of the brace.

Telefix Fork Brace From Bottom

Telefix Fork Brace From Bottom

Fork Tube Clamp Halves Are Matched

Fork Slider Clamp Halves Are Matched

Fork Slider Clamp Halves Are Matched

Fork Slider Clamp Halves Are Matched

The center bracket is made up of two pieces bolted together with two large Allan bolts. I loosen the bolts so I can slide the pieces in and out.

Loosening Center Bracket Large Allan Bolts

Loosening Center Bracket Large Allan Bolts

Center Bracket Distance Is Adjustable

Center Bracket Distance Is Adjustable

Center Bracket Distance Is Adjustable

Center Bracket Distance Is Adjustable

I tilt the center bracket so I can slide it between the fork tubes and then onto the top of the fork slider so the groove in the bracket rests on top of the slider. I leave the two large center bracket Allan bolts loose.

Telefix Fork Brace Center Bracket Mounted on Top of Fork Slider

Telefix Fork Brace Center Bracket Mounted on Top of Fork Slider

The outer half of the fork slider clamp fits on the outside of the fork slider and is secured to the center bracket with four small Allan screws.

Telefix Fork Slider Clamp Outer Half

Telefix Fork Slider Clamp Outer Half

Telefix Fork Clamp Outer Half

Telefix Fork Clamp Outer Half Orientation

I put some blue locktite on the small screws and finger tighten them on each side.

Blue Locktite on Telefix Fork Slider Clamp Allan Bolts

Blue Locktite on Telefix Fork Slider Clamp Allan Bolts

I snug them up to 4 FT-Lbs or 48 IN-Lbs using my inch-pound torque wrench in increments ins a cross-wise pattern so the gap between the outer and inner halves is even.

Installing Telefix Fork Slider Clamp Bolts

Installing Telefix Fork Slider Clamp Bolts

Tightening Fork Slider Clamp Allan Bolts Incrementally and Cross-wise

Tightening Fork Slider Clamp Allan Bolts Incrementally and Cross-wise

Ensure Fork Slider Clamp Gap is Uniform

Ensure Fork Slider Clamp Gap is Uniform

Ensure Fork Slider Clamp Gap is Uniform

Ensure Fork Slider Clamp Gap is Uniform

I check fork stiction as I get each side tight. I find that if I tighten the four small Allan head bolts too tight fork stiction goes up. By experiment I settle on the 48 IN-Lbs value. The Telefix instructions don’t provide a value but mention “lightly” as the tightness of the bolts.

When both sides of the bracket are secured to the fork sliders and I don’t detect an increase in fork stiction, I tighten the large center Allan bolts alternating between them in increments so they don’t tweak the fork sliders. Again, if I tighten these too tight, fork stiction goes up.

Tighten Telefix Center Allan Bolt "Snug" But Not Too Tight

Tighten Telefix Center Allan Bolt “Snug” But Not Too Tight

The instructions say to loosen the two large Allan Bolts 1/4 turn and push the forks up and down several times before “lightly” tightening the two large Allan bolts so I will have to do that later and at that time I’ll put some blue locktite on the threads.

With the two large Allan bolts snugged I test the stiction as shown in the following video.

Instrument Bracket Modifications Needed For Use With Toaster Tan Top Brace

I remove the Toaster Tan top brace now that I have the fork sliders installed and have ensured the fork tubes are parallel in the X and Y plains, the axle slides easily into the fork sliders and the stock fork-fender brace and Telefix brace are installed without any increase in stiction.

Handlebar Bracket Modifications

The  top plate has four holes that allow the handle bar brackets to forward or a bit more backward depending on which set of holes the brackets are installed in. But the Toaster Tan top brace is thicker than the very thin stock BMW plate. Therefore the stock studs installed in the handlebar clamps have to be removed and longer Allan head bolts supplied with the top brace are used to attach handle bar brackets from the bottom of the Toaster Tan top brace.

I use a rag to protect the handlebar top clamp and put them in the rubber jaws of the vice. I use two nuts and lock them together than unscrew the bottom nut to remove the studs from the handlebar top clamp.

Removing Handlebar Clamp Studs

Removing Handlebar Clamp Studs

Removing Handlebar Clamp Studs

Removing Handlebar Clamp Studs

Instrument Bracket Modification

If you move the handlebar clamps to the rearward set of holes, then the instrument bracket front holes are not secured by the handlebar clamp and additional bolts have to be installed to secure them. Since I want the handlebars as far back as I can get them (I’m not 20 any more and neither is my lower lumbar muscles 🙂 )

Instrument Bracket and Toaster Tan Top Clamp

Instrument Bracket and Toaster Tan Top Clamp

In addition the instrument bracket may not fit the slot in the bottom of the Toaster Tan top clamp and mine is one of those that is too wide to fit.

Instrument Bracket Interferes with Toaster Tan Top Clamp

Instrument Bracket Interferes with Toaster Tan Top Clamp

Instrument Bracket Interferes with Toaster Tan Top Clamp

Instrument Bracket Interferes with Toaster Tan Top Clamp

The fix for this is to grind the outer edge of the instrument bracket to allow it to slide into the bottom slot.

Ground Down Edge of Instrument Bracket

Ground Down Edge of Instrument Bracket

Install Instrument Bracket Hardware

I got new rubber grommets and several steel bushings as some were missing when I disassembled the instrument bracket. I also picked up some bolts to use to secure the rear of the instrument bracket to the Toaster Tan top brace.

Instrument Bracket Parts

Instrument Bracket Parts

I insert the rubber grommets and steel bushings into the instrument bracket and test fit the bracket to the bottom of the top clamp in the most rearward position to check alignment.

Steel Bushings Inside Rubber Grommets

Steel Bushings Inside Rubber Grommets

Instrument Bracket Mounting Hardware Modifications

Here is the mounting detail of the smaller rubber grommet with the bolt (M8-1.25 x 30) I used to secure it to the Toaster Tan top clamp.

M8-1.25X30 SS Bolt and Nylock Nut for Front Instrument Bracket Mount

M8-1.25X30 SS Bolt and Nylock Nut for Front Instrument Bracket Mount

Instrument Bracket Rubber Small Bushing Mounting Detail

Instrument Bracket Rubber Small Bushing Mounting Detail

When the instrument bracket mounts to the top clamp there are two metal caps that on the top and bottom of the large rubber grommet.

Instrument Bracket Mounted To Bottom of Top Clamp in Most Rearward Position

Instrument Bracket Mounted To Bottom of Top Clamp in Most Rearward Position

When the instrument bracket mounts to the top clamp there are two metal caps that on the top and bottom of the large rubber grommet.

Instrument Bracket Large Rubber Busing Mouting Detail

Instrument Bracket Large Rubber Busing Mouting Detail

But when using the rearward holes in the Toaster Tan top brace, the metal caps interfere with the holes. And, when using the Allan bolts supplied to mount the handlebar clamps the bolts are too long since they don’t go through the large rubber grommet. So I have to make some modifications.

Alternate Handlebar Bracket Hole is Tight

Alternate Handlebar Bracket Hole is Tight

Alternate Handlebar Bracket Hole is Tight

Alternate Handlebar Bracket Hole is Tight

NOTE:
In the following work, I show adding two steel bushings for the alternate rearward mounting hole. This is NOT necessary. By the time I ground out the bracket holes large enough for the bushings, there is now enough clearance for the Allan head bolt cap. So I removed these bushings when I later added 1″ risers to the handlebar clamps as all four Allan bolts I used here were now too short. I’m leaving the section here since I had to grind out the circular hole in the bracket so is big enough to allow the Allan head bolt to fit, and you can see how an idea one thinks is a clever way to solve a potential problem sometimes turns out to be unnecessary when you finish doing the work 🙂

I got two more of the steel bushings I bought at ACE Hardware for the large grommet. These are sleeves that are close to the same thickness as the rubber grommets with the two metal caps so they will take up the extra length of the Allan head screws supplied by Toaster Tan. But, they are a larger diameter than the original BMW handlebar clamp studs, so I have to grind out the semicircular hole in the instrument bracket and modify the metal caps on the large grommets to get them to fit.

Bushing Doesn't Fit Instrument Bracket Semi-circular Cut-out

Bushing Doesn’t Fit Instrument Bracket Semi-circular Cut-out

I use some Dremel bits to do the grinding.

Dremel Bits For Enlarging Instrument Bracket Cut-out

Dremel Bits For Enlarging Instrument Bracket Cut-out

Bushing Aligned with Hole in Instrument Bracket

Bushing Aligned with Hole in Instrument Bracket

Instrument Bracket Semi-circular Cut-out Enlarged

Instrument Bracket Semi-circular Cut-out Enlarged

Here is how the Allan head bolt and the sleeve fit after the modification.

M8-1.25x65 SS Socket Head Cap Screw with Bushing

M8-1.25×65 SS Socket Head Cap Screw with Bushing

Next I cut out a notch in the metal caps so they will clear the metal bushing.

(L) Notched Cap, (R) Stock Cap

(L) Notched Cap, (R) Stock Cap

Using Notched Cap as Template for Next Cap

Using Notched Cap as Template for Next Cap

Rear Instrument Bracket Cap Cut Out

Rear Instrument Bracket Cap Cut Out

To prevent rust on the areas I ground, I apply some black touch up paint.

Auto Touch Up Paint Applied to Ground Edge of Instrument Bracket to Prevent Rust

Auto Touch Up Paint Applied to Ground Edge of Instrument Bracket to Prevent Rust

Now I install the other Allan head bolt (M8-1.25 x 30) through the large rubber grommet to secure it to the Toaster Tan top plate.

M8-1.25X30 Socket Head Bolt Secures Rear of Top Bracket to Toaster Tan Top Plate

M8-1.25X30 Socket Head Bolt Secures Rear of Top Bracket to Toaster Tan Top Plate

Here is the instrument bracket secured to the Toaster Tan Top Brace.

Instrument Bracket Mount From Bottom

Instrument Bracket Mount From Bottom

Now I mount the handlebar clamps from the bottom using the Allan head bolts. Everything fits 🙂

Toaster Tan Top Plate Ready with Instrument Bracket Ready to Mount on Steering Stem

Toaster Tan Top Plate Ready with Instrument Bracket Ready to Mount on Steering Stem

Toaster Tan Top Plate Ready with Instrument Bracket Ready to Mount on Steering Stem

Toaster Tan Top Plate Ready with Instrument Bracket Ready to Mount on Steering Stem

Toaster Tan Top Plate with Instrument Bracket Ready to Mount on Steering Stem

Toaster Tan Top Plate with Instrument Bracket Ready to Mount on Steering Stem

Install Toaster Tan Top Brace

The top brace and instrument bracket modifications are finished and the forks have been aligned and assembled. I install the Toaster Tan top brace on top of the steering stem and fork tubes. I don’t want to tweak the fork lower triple clamp or the fork braces when I tighten the Toaster Tan steering stem acorn nut.

I use a handlebar in one of the handlebar clamps to act as an anti-torque lever. By positioning the handlebar in my stomach while I torque the nut, the forks don’t push against the fork stops which can misalign the forks.

Using Old Handlebar as Anti-Torque Tool When Torquing Acorn and Fork Tube Top Nuts

Using Old Handlebar as Anti-Torque Tool When Torquing Acorn and Fork Tube Top Nuts

I insert the top brace spaces on top of the fork tubes and then finger tighten the acorn nut to push the top bace down all the way. I torque the top pinch bolts on the Toaster Tan top brace to 15 FT-lbs to secure the brace on the fork tubes.

Torque Toaster Tan Fork Tube Pinch Bolt to 15 FT-Lbs

Torque Toaster Tan Fork Tube Pinch Bolt to 15 FT-Lbs

I modified a 36 mm socket to remove the beveled on the end. That allows the socket to fully engage the flats on the acorn nut and the fork tube top nuts.

36 mm Socket with Beveled End

36 mm Socket with Beveled End

Grinding Off the Bevel

Grinding Off the Bevel

36 mm Socket with Bevel Ground Off Flat

36 mm Socket with Bevel Ground Off Flat

I torque the acorn nut to 80 FT-lbs.

Setting Steering Stem Nut Torque with Anti-Torque Tool Against My Stomach

Setting Steering Stem Nut Torque with Anti-Torque Tool Against My Stomach

Here is the Toaster Tan top brace with the acorn nut installed.

Toaster Tan Top Plate Mounted with Acorn Nut

Toaster Tan Top Plate Mounted with Acorn Nut

Toaster Tan Top Plate is "Meaty" and Should Improve Handling

Toaster Tan Top Plate is “Meaty” and Should Improve Handling

I’ll use the same handlebar anti-torque technique when I torque the fork tube top nuts, but I’m going to wait until the new forks springs arrive. When I measured the length of the original ones they had sacked by more than an inch.

Install New Steering Damper

I had the steering damper bracket powder coated. Here is the cover, the internal parts inside the cover and damper adjusting shaft.

Steering Damper Cover and Adjusting Shaft Parts

Steering Damper Cover, Parts and Adjusting Shaft

The bracket has a finger and spring that pushes the finger into detents along the side of a sliding metal rack. The rack has gear teeth and engages with teeth in the damper adjusting rod. As the damper knob is turned, the it turns the damper shaft which then pushes the rack inside the channel of the cover until the finger falls into a detent to hold the rack in one of three positions.

Spring and Pin

Spring and Pin

Pin Has Tapered End That Fits Into Detents on Edge of Rack Plate

Pin Has Tapered End That Fits Into Detents on Edge of Rack Plate

Inside of Cover Where Rack Plate and Pins Go

Inside of Cover Where Rack Plate and Pins Go

Spring Fits Inside Pin

Spring Fits Inside Pin

Here is how the pin and spring fit in the cover.

Installation of Pins and Springs

Installation of Pins and Springs

Installation of Pins and Springs

Installation of Pins and Springs

I grease the rack plate and put it in the track of the cover.

Rack Plate Installed In Steering Damper Cover

Rack Plate Installed In Steering Damper Cover

The damper shaft teeth fit into the teeth of the rack plate.

Steering Damper Adjusting Rod

Steering Damper Adjusting Rod

How Steering Damper Rod Fits into Rack Plate Gear Teeth Inside Cover

How Steering Damper Rod Fits into Rack Plate Gear Teeth Inside Cover

Before I install the damper rod into the rack plate, I make sure the flat on the top of the rod where the steering damper rod mounts is facing to the rear. When the shaft is in that orientation the steering damper knob is at the “0” position, which provides no damping. That means the ball in rack plate is at the center of the cover.

Steering Damper Rod Orientation When Damper Knob is on "0"

Steering Damper Rod Orientation When Damper Knob is on “0”

I push the rack plate so the ball on the end of the rack is in the center of the plate, insert it over the damper rod and then secure it with the two Allan head bolts.

Steering Damper Cover Allan Bolts

Steering Damper Cover Allan Bolts

Steering Damper Cover Orientation on Lower Triple Clamp

Steering Damper Cover Orientation on Lower Triple Clamp

Then I insert the rubber grommet over the damper rod that secures it in the hole in the Acorn nut and then the steering damper rod.

Steering Stem Shaft Rubber Seal

Steering Stem Shaft Rubber Seal

Steering Damper Shaft Rubber Seal Orientation

Steering Damper Shaft Rubber Seal Orientation

Steering Damper Shaft w/ Rubber Seal

Steering Damper Shaft w/ Rubber Seal

Steering Damper Knob-Center Screw Not Shown

Steering Damper Knob-Center Screw Not Shown

Here are the parts that attach the steering damper to the frame and the ball on the end of the rack pla.

Steering Damper Parts

Steering Damper Parts

 

I install the ball that goes on the bracket on the frame.

Frame Brackert for Steering Damper Ball

Frame Bracket for Steering Damper Ball

Ball Mounted on Frame Bracket

Ball Mounted on Frame Bracket

The damper attaches to the two balls with the fat part of the damper at the front.

Steering Damper Orientation

Steering Damper Orientation

Steering Damper Orientation

Steering Damper Orientation

Each end of the damper has a cup that fits over the ball. I grease the ball before I press the cup over the ball.

Greased Ball Ready To Snap Cup of Damper

Greased Ball Ready To Snap Cup of Damper

The cup is secured so it won’t come off the ball with a wire clip. The straight end fits into a small hole on the side of the cup The clip is rotated so the round end snaps around the base of the cup.

Damper Ball Joint Retaining Clip

Damper Ball Joint Retaining Clip

Ball Joint Installed on Frame Ball with Damper Cup-Note Hole in Side of Cup for Retaining Clip

Ball Joint Installed on Frame Ball with Damper Cup-Note Hole in Side of Cup for Retaining Clip

Damper Retaining Clip Rotated So It Can Snap on Base of Cup

Damper Retaining Clip Rotated So It Can Snap on Base of Cup

Damper Retaining Clip Installed on Cup on Frame Ball

Damper Retaining Clip Installed on Cup on Frame Ball

Ball Joint Installed on Ball on Rack Plate-Note Hole for Retaining Clip

Ball Joint Installed on Ball on Rack Plate-Note Hole for Retaining Clip

Damper Retaining Clip Installed on Cup That Fits on Rack Plate

Damper Retaining Clip Installed on Cup That Fits on Rack Plate

Here is the installed steering damper.

Steering Damper Installed

Steering Damper Installed

I have to install the new fork springs, rork oil and torque the top fork tube cap nuts, but I’m going to wait on that for a bit.

Revisions

2017-08-06  Note added about NOT needing bushing for the handlebar clamp bolt.
2017-08-07  Added steering stop limit bolt install.

9 thoughts on “31 BMW 1977 R100RS Install Steering Stem, Front Forks, Telefix Fork Brace and Toaster Tan Top Brace

  1. Another great write up Brook. I love the care and patience you take when putting it all back together. I wish I had made these modifications away from the standard top plate.

    Do you ever find wear on the inside of the sliders on these 1977-era forks? I’ve rebuilt mine with new stanchions (and damper rings, seals, bumper etc) and aligned them. I get definite movement when rocking forwards and back on full lock with the front brake on. The old stanchions had lost chrome at the lower end from wear. Now I’m wishing I took a better look inside the slider legs!

    Many thanks
    Matt (currently in Thailand on my R75/7)

    • Hi Matt,

      If I understand your comment, you can move the fork lowers front-back with the handle bars turned to the lock, brake on and pushing the bike forward and backward. I suspect that’s normal as the fork slider, or lower, is connected at the bottom to the damper rod and at the top by the fork seals. Both of those have some give in them.

      Note that the forks would not be in this configuration when you are riding. They would be facing forward and would bend a bit when hitting large chuck holes. That is why almost all fork tubes are slightly bent as the forks see forces front to back from bumps, cracks and holes in the road.

      Said differently, I’m not sure what you see is a problem.

      But, I could be wrong. It wouldn’t be the first time. :-0

      Best.
      Brook.

      • Yes that sounds about right. I suppose I am always checking for head bearing play and any other movement in case it is a sign of impending wear/failure. I’m not really used to motorbike forks or certainly BMW’s so it is good to know that this is probably normal. That’s why I asked the guru! Thanks and hopefully not long before we see you take it out for a ride.

  2. Man Oh Man Oh Man! Thank-you, Thank-you, Thank-you!
    Your write-up is just a wonderful display of knowledgeable insight to prevent mayhem. It is the ‘complete’ easily digestible info with videos from the Duane Asherman/Glassman/Snowbum/Clymer explanations I have been struggling with. Oh, Thank-you!
    The wonderful thing is that the specific instructions allow me to assume ‘facts not in evidence’ ( I’ll assume initially that my X and Y planes are within 4 millimeters and just worry about fork tube height and oil weight to remove my lack of stiction over ripply pavement) to adjust my forks simply without a teardown and yet still have the instructions for a complete rebuild if necessary …
    For instance, I do not know if I have the Toaster Tan ‘tube rings’ on my bike since I bought it second hand … and now I can can just check that with the 161 height from the lower triple clamp and lower my fork oil weight to ‘5’ to see if that will remove stiction …

    My story (how kind of you to listen!). I am a not mechanically inclined motorcyclist who has never owned a car and is totally confused by new motorcycles with electronic interdiction everywhere! I felt it best considering mechanic prices to buy an old bike I could work on. Having been impressed by a ’78 R80 I owned and stupidly sold, I bought a ’78 R100/7 – T (A hold-over ’77 with dealer installed Luftmeister touring setup) with 55,000 miles, garage-kept, one owner mechanically thoughtful for a good price of $2,650 in very good condition. The brakes didn’t work and the forks were way too soft, but I rode it home to Las Vegas for L.A.

    Immediately I removed the Luftmeister impedimenta to slim her down. I purchased a Wilbers fork spring kit from Ted Porter, and sourced otherwise a Toaster Tan top clamp used, a Telefix fork brace, a complete fork rebuild kit, and new gaiters. I hired a shade-tree mechanic because the Las Vegas BMW people were uncaring, deceptive, and ridiculously expensive.

    On my first ride my bike started to wobble after 60mph. There was no problem up to 90 before work was done with all the Luftmeister weight before. On a second ‘look’, my mechanic moved the forks down slightly in the Toaster top clamp, and we re-adjusted/checked the steering head bearings so they turned side to side without stiction. Now the bike develops a slight weave at 80 that seems like it will become a wallow. Also, there is no rebound in the fork over small ripples. The bike just ‘skips’ – but large bumps and braking now show no dive. I haven’t ridden the bike for a year as I’m ‘scarred’ and finances would not allow any intervention. Also, I initially replaced the under-tank master cylinder with a fork mounted 14 millimeter master cylinder handlebar mount to find NO improvement in braking at at all! So I just bought a ’12’ mil to attach to see if that will work.

    So now I’m going to put that on, replace my fork fluid with 5 weight as maybe the oil is too heavy to flow through clogged damper holes, check my fork tube height at 160/1 and see if the Toaster clamp has the fork rings in it.
    But NONE of this would be possible without your intensive explanations!
    You Sir, have a place in Heaven as far as I am concerned!
    MUCHO MAHALOS!

  3. Thanks for the write up Brook, it is incredibly helpful!

    I noticed in your instructions you said “I put a bit of anti-seize on the damper rod threads then install the wave washer and nut on the threaded damper rod finger tight.” and then in the photo below you say “Blue Locktite on Fork Damper Thread.”

    Is this contradictory or I missing something? My thought is locktite would be used.
    Thanks again.

    • Hi Mike,

      Duhhhhooooo …. sorry about that. In fact, it’s anti-seize that I use. I don’t want the threads to corrode because it’s not easy to remove the M6 nuts on a rod that can turn. And, that part of the bike can get water under the rubber cover.

      I changed the caption.

      Thank you for finding my mistake. I appreciate your letting me know.

      Best.
      Brook.

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