11 BMW 1983 R100RS Remove Engine Top End

I remove the top end (valve covers, rocker arms, push rods, head, head gasket, cylinder and piston) before I take the engine out of the frame. The design of the airhead engine makes removing the top end a simple job that can be done with the tools in the on-board tool kit. For the 1983 engine, also need a set of snap ring pliers to remove the wrist pin snap ring, but on earlier models that used the wire clip to retain the wrist pin, you could remove that with the flat blade screw driver. πŸ™‚

Here is a short video showing all the steps. In all honesty, it takes just about as long to take one side of the top end off as it takes to watch the video.

VIDEO: 1983 BMW R100RS How To Remove the Top End

Remove Valve Covers

First I remove the spark plug.

Spark Plug

Spark Plug

Remove Spark Plug

Remove Spark Plug

The insulator on the plug looks okay, perhaps just a bit rich.

Spark Plug Insulator Detail

Spark Plug Insulator Detail

The valve covers are secured by three nuts with washers; the center chromed nut and two 6 mm nuts at the upper left and lower right corners of the valve cover. I remove these and pull the valve cover off.

Valve Cover Center Nut Location

Valve Cover Center Nut Location

Valve Cover 6 mm Nut Location-2nd is At Opposite Side On the Bottom

Valve Cover 6 mm Nut Location-2nd is At Opposite Side On the Bottom

Remove Valve Cover Center Nut

Remove Valve Cover Center Nut & Washer

Valve Cover Center Nut Detail

Valve Cover Center Nut Detail

Removing Valve Cover 6 mm Nut & Washer

Removing Valve Cover 6 mm Nut & Washer

Valve Cover 6 mm Nut Hardware Detail

Valve Cover 6 mm Nut Hardware Detail

This version of the of the valve cover has “R” or “L” stamped in the middle to indicate which side the cover goes on. The letter should be on the bottom when the cover is mounted correctly so the horizontal strips are level.

"R"ight Valve Cover-"R" Goes On The Bottom

“R”ight Valve Cover-“R” Goes On The Bottom

"L"eft Valve Cover Mark-Goes on Bottom

“L”eft Valve Cover Mark-Goes On Bottom

This one has silicone gaskets. I don’t like them, so I put them in the appropriate storage bin. I will replace them with solid gaskets.

Silicone Valve Cover Gasket

Silicone Valve Cover Gasket

Silicone Valve Cover Gaskets Placed In Appropriate Storage Bin

Silicone Valve Cover Gaskets Placed In Appropriate Storage Bin

Loose Paint Bits Inside The Valve Cover

Loose Paint Bits Inside The Valve Cover

Someone repainted the covers and the paint inside the cover is flaking off. That’s not helpful as it can fall into the oil pan and potentially get circulated through the oil pump before it reaches the oil filter. I’ll clean this up when I repaint the valve covers and not put paint inside the valve covers.

Remove Cylinder Heads

With the valve cover off, I can see the rocker arm assemblies.

Rocker Arm Assemblies Are Visible With Valve Cover Removed

Rocker Arm Assemblies Are Visible With Valve Cover Removed

Each rocker arm assembly is secured with two nuts on the cylinder studs. There are also two other nuts at the 12:00 and 6:00 positions of the head that secure it to the cylinders. Once these six nuts are removed, the head comes off.

Check For Damaged Cylinder Stud Threads

Before I remove the rocker assemblies, I use a torque wrench to test the cylinder stud threads in the engine block. These threads can pull out if someone has over torqued them and now is the time to find out if any of them are damaged. I set the torque wrench to 23 FT-Lbs and tighten each nut. The wrench should click indicating the cylinder stud can hold that much torque. If it won’t click and the nut keeps turning, then the threads in the engine block are damaged and you have to repair them.Β  You can see how to do that here:

These cylinder studs were tight so no need to repair the threads in the engine block.

Loosen Tappet Adjusters & Remove Head Nuts

I loosen the lock nut on the tappet adjusters and then back the adjusters all the way out until I can spin the push rods and the rocker is loose.

Tappet Adjuster Assembly

Tappet Adjuster Assembly

Loosening Tappet Adjuster Lock Nut

Loosening Tappet Adjuster Lock Nut

Tappet Adjuster Backed All The Way Out So Push Rod Spins & Tappet is Free to Move

Tappet Adjuster Backed All The Way Out So Push Rod Spins & Tappet is Free to Move

Then, in a cross-wise pattern, I loosen each of the six nuts holding the head on a small amount, maybe an eight of turn. I continue loosening in the cross-wise pattern a bit more until the nuts are easy to remove with my fingers. The 12:00 and 6:00 nuts will loosen almost immediately, but the four on the cylinder studs will take several rounds if loosening until the nuts are free. I loosen the cylinder stud nuts a little at a time to relieve the pressure incrementally so the heads are not subjected to a lot of uneven stress. Since they are aluminum, an ounce of caution is worth it to avoid any opportunity to warp them.

Rocker Arm Assembly Showing Two Cylinder Studs That Secure It

Rocker Arm Assembly Showing Two Cylinder Studs That Secure It

Loosening Cylinder Stud Nuts-In Stages, Cross-wise Pattern

Loosening Cylinder Stud Nuts-In Stages, Cross-wise Pattern

Rocker Assembly Cylinder Stud Nut Mounting Detail

Rocker Assembly Cylinder Stud Nut Mounting Detail

12:00 Head Stud Hardware Detail (Same as 6:00 Stud)

12:00 Head Stud Hardware Detail (Same as 6:00 Stud)

The four nuts on the cylinder studs have a round boss on one end that fits against the face of the pillow block.

Rocker Assembly Nut Detail-Round End Goes Against Pillow Block

Rocker Assembly Nut Detail-Round End Goes Against Pillow Block

Remove Rocker Arms

Once the six nuts are removed from the head, I grasp a rocker assembly by the upper and lower pillow blocks and pull it off the cylinder studs. Some rocker assemblies have needle bearings inside, so pinching the assembly by the pillow blocks keeps them in place. And these rockers have a machined hole that aligns them on the bushing at the top of the cylinder studs to center the assembly automatically. Earlier designs did not have this feature.

Grasping Pillow Blocks To Pull Rocker Assembly Off Cylinder Studs

Grasping Pillow Blocks To Pull Rocker Assembly Off Cylinder Studs

Rocker Assembly Removed-Machined Holes Fit Bushing on Cylinder Studs

Rocker Assembly Removed-Machined Holes Fit Bushing on Cylinder Studs

Bushing On Cylinder Stud Positions Rocker Assembly Correctly

Bushing On Cylinder Stud Positions Rocker Assembly Correctly

If you inspect the finger of the rocker arm, you may see discoloration. This is not abnormal but is caused by the heat treating that hardens the steel in the tappet of the rocker arm.

Heat Treating of Finger On Rocker Arm Can Cause Discoloration-It's Normal

Heat Treating of Finger On Rocker Arm Can Cause Discoloration-It’s Normal

I put each rocker assembly along with the two nuts in a labeled bag, e.g., Left Intake. I don’t want to mix these up when I put the heads back on.

Rocker Arm Assemblies in Marked Bags So They Go Back Where They Belong

Rocker Arm Assemblies in Marked Bags So They Go Back Where They Belong

Remove Push Rods

Once the rocker assembly is removed, I pull each push rod out.

Push Rods Are At the Bottom of the Head Assembly

Push Rods Are At the Bottom of the Head Assembly

If you do it slowly, you will feel resistance and then rod will pop free. Push it back in and do this again. This slight popping of the rod indicates the ball on the lower end is seated in the cup of the cam follower. This is what you want to feel when you put the push rods back in to ensure the bottom ball on the rod is seated in the cam follower cup.

DANGER:
It is possible to put the push rod in the push rod tube and have it rest on the edge of the cam follower. If you assemble the head this way the push rod and cam follower will be damaged.

I put a label on each push rod to indicate where it goes, and which end is at the top, e.g, “L-EX-TOP”. Although the balls on either end of the rod are the same, each ball has mated to it’s corresponding part and it’s nicer to keep the rod orientation the same.

Push Rods Labeled Before Removing

Push Rods Labeled Before Removing

Pull Head & Head Gasket Off the Cylinder

I often use a rubber mallet to tap the fins around the bottom of the head to break it free from the head gasket. Gentle taps toward you around the perimeter while you pull the head toward you are enough. It will slide out on the cylinder studs. Then I remove the head gasket from the top of the cylinder.

Here is what the head looks like after it is removed.

Head Removed Showing Valves and Valve Springs

Head Removed Showing Valves and Valve Springs

The inside shows the valve faces. There is carbon build up, but it is not oily indicating the valve guides are not leaking oil.

Inside of Head Showing Valve Faves and Hemispherical Combustion Chamber [Yes, IT'S A HEMI!!! :-) ]

Inside of Head Showing Valve Faves and Hemispherical Combustion Chamber [Yes, IT’S A HEMI!!! πŸ™‚ ]

Remove Cylinders

Before I remove the cylinders, I take the head gasket off. It should come off easily, but if it’s stuck, use a small screw driver blade to gently free it from the cylinder face. Don’t gouge that face with the screw driver.

Head Gasket

Head Gasket

Remove Head Gasket

Remove Head Gasket

The cylinders have a sleeve that fits into the bore of the engine block. Usually I can wiggle the cylinder while pulling it out and get it come out of the block. It it’s stuck, use a rubber mallet as I described for the head to get it loose.

As you pull it toward you, it will become harder to move. The push rod tube rubber seals interfere with the bottom frame tube. If you can, rotate the seals 90-degrees and they will slide by the frame easier. If they won’t rotate, just pull harder while rocking the cylinder back and forth to wiggle the seals past the frame. BUT, I don’t get too aggressive. As soon as the cylinder slides freely again, I pull it out until the connecting rod is exposed and the piston is partially out of the cylinder. Then I take a piece of garden wire and run it under the connecting rod and over the top cylinder studs to suspend it. That way, when the piston comes free from the cylinder, there is no chance the rod will drop and nick the sealing surface of the engine block.

Wire Up Connecting Rod To Protect Engine Case From Nicks

Wire Up Connecting Rod To Protect Engine Case From Nicks

Remove Pistons

I pull the cylinder out farther until the wrist pin and snap ring are exposed but the piston is still in the cylinder. Then I use snap ring pliers to remove one snap ring. I like to remove the one on the intake side of the piston. It is a “use once” item, so I will replace them. I don’t remove the other one as it becomes a “handle” to help remove the pin from the other side.

Wrist Pin Snap Ring

Wrist Pin Snap Ring

Snap Ring Pliers

Snap Ring Pliers

Remove Snap Ring

Remove Snap Ring

Snap Ring Removed-It's "Use Once" So I Will Replace Them

Snap Ring Removed-It’s “Use Once” So I Will Replace Them

The wrist pin often is loose enough that it can be pushed out to one side with my finger. This one is easy to slide.

This Wrist Pin Moves Easily By Hand

This Wrist Pin Moves Easily By Hand

But, if it isn’t sliding out under finger pressure, I use two 3/8 inch socket extensions, a short one and a longer one, and insert the square end of short one into the hole in the wrist pin. It will go in until the shoulder abuts the wrist pin. Then I gently tap on the end of the second extension to slide helps slide the wrist pin out. This is why I leave the piston in the cylinder so as I tap on the socket extension, It isn’t putting any sideways force on the connecting rod.

Socket Extensions For Use As Wrist Pin Drift

Socket Extensions For Use As Wrist Pin Drift

You Can Use the Socket Extensions To Tap The Wrist Pin Out If You Need To

You Can Use the Socket Extensions To Tap The Wrist Pin Out If You Need To

When the pin if far enough out the other side, I grab it and twist it while pulling it out to get it far enough out that the piston is free of the connecting rod. I hang on to the piston while doing this so I can feel when it is free. When it is I slide the cylinder with the piston off the connecting rod. Then, while holding the piston, I remove the cylinder to free the piston and then I remove the from between the cylinder studs.

DANGER:
If you failed to secure the connecting rod from falling at this point, it can fall and nick the machined surface of the engine block. That will cause an oil leak. You do not want that to happen.

NOTE:
If you wish, you can keep the piston in the cylinder and remove them together. In fact, if you want, you can pull the cylinder off the piston just far enough to expose the wrist pin but not far enough to allow the piston rings to exit the cylinder. After you push the wrist pin far enough out to slide the piston off the connecting rod, you can remove the cylinder with the piston captive inside it. This is a good way to do this when the reason to remove the cylinder and piston is to install new push rod tube seals. This method does not disturb the rings nor risk breaking them when you insert the piston into the cylinder.

Pulling Wrist Pin Out To Free It From Connecting Rod

Pulling Wrist Pin Out To Free It From Connecting Rod

Piston Free From Wrist Pin

Piston Free From Wrist Pin

Piston Removed

Piston Removed

At soon as the piston is off the connecting rod, it can drop down and nick the machined surface of the engine case. That’s why I secured it with garden wire as soon as I pulled the cylinder far enough out to expose it so I won’t forget to secure it.

Previously Installed Wire Suspends Connecting Rod So It Won't Drop & Nick The Case

Previously Installed Wire Suspends Connecting Rod So It Won’t Drop & Nick The Case

On the bottom of the cylinder is the push rod tubes with the rubber seals. These are hard as a rock which is why they are leaking.

Push Rod Tubes & Seals-The Seals Are Hard As a Rock And Leaking

Push Rod Tubes & Seals-The Seals Are Hard As a Rock And Leaking

On the 1983 engines, the top cylinder studs have a small o-ring that creates an oil seal. Oil to the rocker assemblies flows out of the engine block along the the hole in the cylinder the cylinder studs fit into. If these are missing when you assemble the top end, you will know it pretty quickly as oil with be coming out around the top of the cylinders.

On the bottom of the cylinder where the sleeve goes into the engine block is a large o-ring. I will replace it when I put the top end back together.

Cylinder Base Has A Large "Use Once" O-Ring

Cylinder Base Has A Large “Use Once” O-Ring

Top Cylinder Studs Have Small "Use Once" O-rings

Top Cylinder Studs Have Small “Use Once” O-rings

Finishing Up

I pack the engine case with two shop rags, one on the bottom of the connecting rod and one on top. The bottom rag keeps the rod from dropping and nicking the engine case. Then I move the garden wire and put it through the rod bushing so the rod is doubly protected from falling.

Engine Bore Packed with Shop Rags and Wire Through Connecting Rod Bushing

Engine Bore Packed with Shop Rags and Wire Through Connecting Rod Bushing

Here is a view of the cam followers that the bottom ball of the push rods fits into. In the center is the cup the ball fits into.

DANGER:
When assembling the top end, if you don’t get the push rod into the cup of the cam follower, and instead, it sits on the edge, you will damage the follower and the push rod. That’s why testing by pulling gently on the rod to feel it “pop” out of the cup is important as that ensures the ball is seated properly in the cup.

Grunge From Leaking Push Rod Seals & Can Followers

Grunge From Leaking Push Rod Seals- You Can See the Cam Followers with Shiny Cups For Bottom Balls of the Push Rods

The machined surface of the engine block the cylinder sleeve fits into has hardened sealant caked on to it. I will have to carefully clean this off before putting the top end back together.

Baked On Gasket Sealant

Baked On Gasket Sealant

Here is what the bikes looks like now. It’s almost ready to separate the engine from the frame.

Top End Removed

Top End Removed

Top End Removed

Top End Removed

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