1977 BMW R100RS Install Connecting Rods and Top End

Previously, I removed the heads, cylinders, pistons, rings and connecting rods. I installed new rocker arm needle bearings to replace the broken bearing cages. I disassembled the heads and inspected the valves and seats. You can read how I did that work here.

You can read about how I did this work here:

Top End Rebuild Work

I had the Nikasil cylinders replated and honed to match the new high compression (9.5:1) pistons. I had the connecting rods refurbished and I had the heads rebuilt. So now it’s time to put it all back together again.

The cylinders had the push rod tubes and the two short studs at the 12:00 and 6:00 position of the heads removed, so I also have to install them.

I started from this:

Ready To Remove Heads & Cylinders

Ready To Remove Heads & Cylinders

Engine Out of Frame

Engine Out of Frame

Piston Crown with Carbon

Piston Crown with Carbon

Rod Components

Rod Components

Score in Right Cap Bearing Sheel

Score in Right Cap Bearing Sheel

Right Side Crankshaft Throw

Right Side Crankshaft Throw

Cylinder Grunge

Cylinder Grunge

Left Exhaust Lower Rocker-Recovered Needle Bearings and Cage Pieces

Left Exhaust Lower Rocker-Recovered Needle Bearings and Cage Pieces

Right Intake Rocker Busing

Right Intake Rocker Busing

Right Intake Rocker Shaft

Right Intake Rocker Shaft

Valve Assembly Components

Valve Assembly Components

And finished with this:

Push Rod Tubes Installed

Push Rod Tubes Installed

Piston with Rings Installed

Piston with Rings Installed

Sliding Cylinder and Piston onto Long Cylinder Studs

Sliding Cylinder and Piston onto Long Cylinder Studs

Ready to Snug Cylinder to Engine Block-Push Rod Tube Rubbers Started

Ready to Snug Cylinder to Engine Block-Push Rod Tube Rubbers Started

Left Head Orientation-Exhaust to Front

Left Head Orientation-Exhaust to Front

Top End Installed

Top End Installed

Valve Cover Installed

Valve Cover Installed

4 thoughts on “1977 BMW R100RS Install Connecting Rods and Top End

  1. Did you replace the small end bearings the bronze ones ? and how did you do that I find that they get loose on the Piston pins! Did you replace the cam chain that’s always a good thing to do…

    Instead of buying Pistons 9.5 I think I would just shave the head about .030 where did you get the rechroming cylinders done?

    Great looking engine though on the outside probably will be very good for at least a hundred thousand miles

    • Hi Fraser,

      Tom Cutter at rubber chicken racing garage installed the new small end bushings and honed them to fit the gudgeon pins.

      Yes, I replaced the timing chain several months ago. I documented that and you will find the link on the right side of any of my pages.

      No, I’m not interested in potential problems with valve clearance and changes to squish bands, etc. The pistons were pitted anyway so I bought BMW 9.5:1 pistons they sell in Europe, but not the US, for use with Nikasil cylinders.

      Tom Cutter has an arrangement with a firm that bores and does the Nikasil plating to Tom’s clearance specifications. I’ve seen a couple advertisements for firms that do Nikasil plating in the US. I think a Google search will find them.

      Thank you. The project is coming along.

      Best.
      Brook.

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