1973 BMW R75/5 Rebuild: Install the Engine and Transmission

It’s time to put parts back into the frame :-).  The first to go in is the engine followed by the transmission. You can read about what I did here:

I used information from the following resources to plan this work.

As I had the engine stripped down, I was able to lift it into the frame by myself using some straps so my hands weren’t under the oil pan. The transmission isn’t very heavy, but there isn’t much clearance when the engine is installed and I had to remove the kick start lever or it wouldn’t fit.

Here are a couple pictures from the write-ups.

Engine Installation

Polished Engine

Polished Engine Ready to Install Into The Frame

Engine In Frame Resting on Lift

Engine In Frame Resting on Motorcycle Lift

Left Side Shackle and Side Stand

Left Side Shackle Keeps Side Stand on Pivot Pin (Looking Toward Rear)

Engine In Frame & Secured to Lift

Engine In Frame & Secured to Lift

Transmission Installation

Refinished Left Side

Refinished Transmission Ready to Install in the Frame

Clutch Throwout Parts

Clutch Throw Out Assembly Parts

Frame Protection

Frame Protection Before Inserting Transmission In the Frame

Clutch Throwout Rod Bearing Assembly

Clutch Throw Out Bearing Assembly Showing Direction and Order of Insertion into Bearing Housing

Job Done

Transmission Install Job Done

1973 BMW R75/5 Rebuild: Wheel Polishing, Bearings and Spokes

The wheels are the next project to work on. The plan is to take them apart, replace the chrome spokes and nipples with stainless steel spokes, inspect, lube and set the preload on the wheel bearings.  I decided to have Woody’s Wheel Works inspect the bearings and lace up the new spokes.  Here is a link to the write-up on this work.

When I removed the bearing cover on the rear wheel, the left side bearing outer race had loosened and spun in the aluminum hub.   There are various options to fix this including:

1. Using locktite on the outside of the outer race to secure it to the aluminum hub.
2. Staking the outer race to try and keep it captive in the aluminum hub.
3. Adding a shim around the outside of the outer race so it is captive in the aluminum hub
4. Buy a new hub.

I posted my problem to the airhead forum on the Micapeak site looking for input on these options and any other ideas. The consensus is:

  • Option 1 can work, but also can fail
  • Option 2 always fails,
  • Option 3 works well,
  • Option 4 is expensive and since new hubs are no longer available from BMW, is not a viable option.

I also got a response from two folks in Australia with a variation on shimming the outer race. Their fix uses a thin steel sleeve called Speedi-Sleeve, provided by SKF bearing company. It is designed for use on shafts that have been scored by the shaft seal. Adding a Speedi-Sleeve stops the oil leaking past the seal and retains use of the original oil seal. The sleeve that fits the R75/5 wheel bearing is #99157. It’s 0.28 mm or 0.011 inch thick so it adds 0.56 mm or 0.022 inch of material to the aluminum hole holding the bearing. It is installed on the outer race with a special tool. Then the bearing stack is assembled using the axle with a spacer and is put into the heated aluminum hub. This is the standard procedure for installing the bearing stack into the aluminum hub. When the hub cools, it contracts around the Speedi-Sleeve and outer race shell and should hold the shell captive to the hub. This is the solution I choose and had Woody’s install the Speedi-Sleeve.

Here are some pictures from the write-up.

Rear Wheel, Bearing Cover Side

Rear Wheel, Hub Cap Side

Rear Rim Gouges

Rear Rim Has Deep Gouges

Bolt Cutter

Brute Force Approach: Using Bolt Cutter to Cut Spokes

Front Rim with Cut Spokes

Front Rim with Cut Spokes and Hub Removed

Removing Nipple with Power Screw Driver

Non-Distructive Approach: Removing Nipples with Power Screw Driver

Bearing Stack, Outside (Left) to Inside (Right)

Bearing Stack, Outside (Left) to Inside (Right): Bearing Cover & Gasket, Inner Bearing Race, Outer Bearing Race, Wedding Band, Inner Spacer, Outer Spacer

Polished Hubcaps

Cleaned and Polished Hub Caps

Woody's Wheel Works Final Product

Woody’s Wheel Works Complete Front Wheel

1973 BMW R75/5 Rebuild: Replace Alternator Brushes and Front Crankshaft Seal

I had replaced the leaking camshaft seal earlier and you can read about how I did that here:

The alternator has 97,500 miles on it, so I decided to replace the brushes.  I hadn’t seen evidence of oil leaks from the front crankshaft seal, but it turns out its very easy to replace it when I was replacing the alternator brushes.  I also cleaned the rust and flaking paint off the starter motor and then painted it to stop any further rusting.

You can read about what I did on both of these tasks here:

I bought the brushes at Euro Motoelectrics which is here in Denver, CO.  I also picked up a hardened bolt to extract the alternator rotor from the tapered nose of the crankshaft.

Rotor Puller Bolt and New Brushes

Rotor Puller Bolt and New Brushes

These jobs went pretty quickly and were straight forward.  I found I needed a  200/260 watt soldering iron to remove the old solder and solder the new brushes as they are soldered to a large plate that dissipates heat pretty well.  My 140 watt gun wasn’t up to the task.

Old Brushes Removed from Holder

Old Brushes Removed from Holder

New Brushes Installed

New Brushes Installed

Shaft Seal Puller Installed

Shaft Seal Puller Installed With Adjustable Pivot Pin Resting on Engine Housing

At this point, the engine work I planned is done.  Here is the painted starter motor installed and the engine after polishing up the cases.

Painted Starter Motor Installed

Painted Starter Motor Installed

Polished Engine

Polished Engine

Polished Engine

Polished Engine

1973 R75/5 Rebuild: New Oil Pan Gasket and Camshaft Seal

Both of these showed signs of leaking oil and I replaced them.  You can read about how I did this here:

When replacing the oil pan gasket, I also cleaned the oil pickup screen and checked to be sure the bolts holding the pickup are tightened to the proper torque, 72 INCH/Pounds, not FOOT/Pounds.  I used an INCH/Pound torque wrench on them and also on the oil pan bolts which were set to 70 INCH/Pounds in several stages.  These bolts are easy to strip out unless you use an INCH/Pound torque wrench.

I put in new points and a condenser when I replaced the cam shaft seal and replaced the timing plate machine screws with two Allan head cap screws, M4x0.7×10. Now its easy to adjust the timing plate points cam with the centrifugal advance weights installed with a small Allan head wrench. And, I won’t be wallowing out the slot on machine screws as happened in the past.

I used my larger adjustable seal puller to remove the camshaft seal, but it makes me nervous since the camshaft seal is small and I don’t want to score the camshaft. After I got the camshaft seal pulled, I looked for a puller for small seals. I found a very promising one, Lisle 58430 shaft seal puller. It’s available at some auto parts stores, but I ordered mine from Amazon.

Lisle_58430SealPuller

Lisle 58430 Shaft Seal Puller

I think this will work very well on future seal pulling jobs.

 

 

 

 

Here are a few pictures of the work.

Replacing Oil Pan Gasket

Engine on Side to Remove Oil Pan

Engine on Side to Remove Dirty Oil Pan

Permatex Gasket Remover Soaking In

Permatex Gasket Remover Soaking In

Checking Torque (72 INCH/pounds) on Oil Pickup Bolts

Checking Torque (72 INCH/pounds) on Oil Pickup Bolts

Clean Pan Mating Surface

Clean & Polished Pan Mating Surface

Clean Oil Pan with New Pan Gasket

Clean Oil Pan with New Pan Gasket

Replacing Camshaft Seal

Leaking Cam Shaft Seal

Leaking Cam Shaft Seal

Points Plate

Points Removed and Timing Plate Ready to Remove

Old Seal

Old Seal

Driving Cam Shaft Seal

Driving Cam Shaft Seal with 5/8 Inch Spark Plug Socket

New Points and Allen Head M4x10 Cap Screws

New Points and Allen Head M4x10 Cap Screws

1973 R75/5 Rebuild: Installing a New Clutch

I decided to replace the original clutch after inspecting it and measuring the parts. Many were close to, or past, the minimum thickness. You can read about the procedure I used to install the new clutch in this web page:

I ordered the new clutch parts from Tom Cutter at Rubber Chicken Racing Garage who sent me the following:

21 21 1 250 035 Diaphram Spring (Heavy Duty)
21 21 1 251 801 Pressure Plate
21 21 1 236 332 Clutch Plate
21 21 1 231 666 Compression Ring
21 21 1 231 463 Filister Head Cap Screw (6)

Here are a couple of the pictures included in write-up.

Old (top) & New Clutch Parts

Old (top) & New Clutch Parts, Inside to outside, Left-to-Right

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Supplies and Special Tools to Mount the Clutch

Toothpick Application of Thin Layer of Honda 60 Molypaste to Edge of Fingers of Diaphragm Spring

Toothpick Application of Thin Layer of Honda 60 Molypaste to Edge of Fingers of Diaphragm Spring

Clutch Diaphragm Spring Against Face of Flywheel

Clutch Diaphragm Spring Against Face of Flywheel

New Clutch Bolts and Long Bolts

New Clutch Bolts Inserted and Long Bolts Ready to be Removed.

Transmission Aligned with Engine

Transmission Aligned and Tight to the Engine Clutch Housing