I remove the crankshaft to check the condition of the main bearings. In order to remove it, I have to remove the camshaft first. I use the tools I bought from Cycle Works to remove the crankshaft.

Cycle Works Stage III Tools

I asked Matt Parkhouse, a long time airhead mechanic who lives about two hours from me, to assess the condition of the crankshaft main journals and the main bearings. He found the front bearing was serviceable but the rear main bearing was just outside the maximum clearance. He replaced the bearing and now the front and rear main bearing clearances are close.

Measuring ID of Original Rear Main Bearing

Since I have to heat the front of the engine block to 275 F, I removed the stater motor and crankcase vent housing hose so they would not be damaged.

Here is the block with the crankshaft and camshaft removed.

Engine Block Looks Empty

You can read about how I do this work here:

• 11 BMW R100RS Remove Camshaft and Crankshaft

And here is a short video of the highlights of the work:

VIDEO: 1983 BMW R100RS Remove Camshaft and Crankshaft

I remove the inner timing cover to get access to the timing chain, the crankshaft timing sprocket and nose bearing, the timing chain tensioner and the chain rubbing block (aka, slide rail).

Inner Timing Cover Exposed After Electrical Components Removed

Inner Timing Cover Removed

The chain, sprocket, nose bearing, chain tensioner and rubbing block wear and this affects timing. The wear can be great enough that you can hear the timing chain rattle.

What’s Under The Inner Timing Cover

You can read about how I do this work here:

• 11 BMW 1983 R100RS Remove Timing Chain, Crankshaft Nose Bearing & Sprocket, & Front Crankshaft Seal

I made a short video summarizing the procedure that you will find here.

I will replace the crankshaft sprocket, nose bearing, chain tensioner, rubbing block and the internal components of the oil high pressure relief valve. I will post a separate write-up showing how I do that.

I am going to replace the timing chain, crankshaft sprocket, crankshaft nose bearing, and the front main seal. I’m also going to pull the crankshaft to inspect the main bearings.

But first, I have to remove the electrical components and wiring inside the front engine cover that includes the diode board, alternator and ignition sensor, aka, the “bean can”, aka, the “electronic points”. I plan to upgrade the alternator and diode board to a 400 watt system. I also plan on opening the bean can to lube the advance mechanism and replace the Hall effect sensors.

Here is the before and after pictures.

Diode Board, Alternator, Ignition Sensor Are Inside Front Engine Cover

All Gone 🙂

You can read about how I did this work here:

• 12 BMW 1983 R100RS Remove Diode Board, Alternator & Electronic Ignition Sensor

And, I shot a video of this work which is a bit long at 20 mins.

VIDEO: 1983 BMW R100RS Remove Diode Board, Alternator and Ignition Sensor

My goal in the video is to explain more about what the wiring under the front engine cover does and how it’s routed, as well as show how to remove all the components, so that added to the length. I’ll try to keep future videos shorter.

I previously removed the clutch, flywheel and rear main seal so I can replace the crankshaft rear main seal, the flywheel o-ring and the oil pump cover o-ring. You can see how I did that work here:

• 21 BMW 1983 R100RS Remove Clutch
• 11 BMW 1983 R100RS Remove Flywheel & Rear Main Seal

The inside of the bell housing as well as the shelf under the transmission showed oil leaks, so one, or all, of these are the likely culprits.

Grunge Inside the Bell Housing Suggests O-rings and/or Rear Main Seal Leaks

Oil & Grudge On The Shelf Under The Transmission

When I opened up the oil pump to take measurements and do a visual inspection, I decided that I had to replace the oil pump due to a lot of wear and tear to the rotors inside the pump. You can see how I removed and measured the oil pump here:

• 11 BMW 1983 R100RS Remove & Inspect Oil Pump

Scratches On Lobe of Oil Pump Inner Rotor

Grooves on Face of Oil Pump Outer Rotor

When I first got the bike, in debugging a low oil pressure light that came on, I discovered that the oil filter high pressure bypass valve was hanging by a thread. So, unfiltered oil was circulating, but I didn’t know for how long. Based on the condition of the oil pump and the scores I found in the rod bearings, I think unfiltered oil circulated for while.  Not what I wanted, but I’m glad I took a look at the pump.

You can read about how I did the work here:

• 11 1983 BMW R100RS Install Rear Main Seal, Oil Pump Cover O-ring & Flywheel

And, you can see a short video that summarizes the work here:

Due to what I found with the oil pump, I’m making a detour on the project. I’m going to pull the crankshaft to inspect the main bearings. I suspect I won’t like what I find there either, but it makes sense to take a look.

I have been delinquent working on this project for a few months.  I got distracted with preparations for riding out to the 40th anniversary rally for the R65LS-R80G/S and then, I was lazy when I got back.

Below is my documentation of this work in write-ups and short videos.

NOTE:
I edited the Remove Clutch video and reposted it on YouTube. If you use the older version of this blog, the link will fail. I edited the link below so it points to the new video.

• 21 BMW 1983 R100RS Remove Clutch
  Video-> 1983 BMW R100RS Remove Clutch
• 11 BMW 1983 R100RS Remove Flywheel & Rear Main Seal
  Video-> 1983 R100RS Remove Flywheel & Rear Main Seal
• 11 BMW 1983 R100RS Remove & Inspect Oil Pump
  Video-> 1983 R100RS Inspect Oil Pump

When parts arrive, I’ll get the back end of the engine buttoned up and, as is my affliction, I will write-up and film the corresponding documentation.

Here are a couple of pictures from the documentation.

Clutch Assembly Uses Six Bolts at 12:00, 4:00 and 8:00

Diaphragm Spring Fits In Hollow of the Flywheel Face

Removing Flywheel Bolts with Impact Wrench

Removing Seal with Cycle Works Jig

Measure Oil Pump Outer Rotor End-Play