Due to the 83,000+ miles on the bike, I’m going to replace the following parts:

• Timing Chain
• Timing Chain Tensioner & Slide Rail
• Crankshaft Nose Bearing
• Crankshaft Timing Sprocket
• Front Main Seal
• Inner Timing Cover Gasket & “Doughnut” Gaskets

This write-up shows how to remove these parts. A separate write-up will show how to install the new parts.

I’m going to open the oil high pressure relief valve and inspect it as well.

Since this model has the electronic tachometer and electronic ignition with the “bean can” ignition sensor, there is no camshaft seal. The bean can use an o-ring and I’ll replace that when I install electrical components under the front engine cover which I document in a separate write-up.

I already removed the electrical components and wiring from inside the front engine cover. You can read about how I removed the electrical components here.

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

These have to be removed so I can remove the inner timing cover to get access to the timing chain, crankshaft nose bearing and timing chain sprocket, and the oil high pressure relief valve.

Tools

I use tools from Cycle Works to remove the crankshaft nose bearing and timing sprocket and to install the new parts. Cycle Works sells three levels of tools, Stage I, Stage II and Stage III.

The Stage I kit lets you remove/install the crankshaft nose bearing and timing sprocket, but does not include a tool to remove the inner timing cover (shown as XXed out in the picture below). I show how to remove the inner timing cover without a tool in this write-up.

The Stage II kit includes a tool to remove/install the front main bearing carrier that can also be used to remove/install the inner timing cover.

I purchased the Stage III kit which includes all the tools I need for this work along with the tools to remove the front and rear main bearings.

I also use MAP gas for heating parts to aid in disassembly.

Video

I shot a video summarizing this work.

Remove Ground Wire “Octopus”

There is an “octopus” of ground wires on this bike to ensure a solid ground for the diode board with the original rubber diode board mounts and the painted inner timing cover. I replaced the rubber mounts when I first got the bike and installed solid metal mounts. To remove all the legs of the octopus, I remove the top two mounts to free two of the grounds.

Remove Inner Timing Cover Bolts & Nuts

Before I get started, I wrap a couple layers of masking tape around the tapered nose of the crankshaft where the alternator rotor mounts. This is a precision machined surface and I want to protect it from getting dirty or dinged while I work.

The inner timing cover is secured to the engine block with nine Allan bolts and three Allan washers in the locations shown in the picture below.

I break them loose in a cross-wise pattern. Then I remove them and place each in a piece of cardboard with an outline of the timing cover, what call my “Bingo” card, so I make sure I get them all and each is placed in the location in the card corresponding to where they are in the inner timing cover.

NOTE:
The cardboard fastener holder is not really needed since all the bolts are the same size/length and you can’t accidentally install one of nuts incorrectly. That said, this is part of my “belt and suspenders” discipline when removing a lot of hardware particularly if it’s the first time I’ve removed that hardware. The cardboard fastener holder makes sure if there are any size/length differences in the fasteners, I don’t  have to figure that out when I reinstall the hardware. I learned this when I was working on vintage Triumph/BSA’s where they loved changing fastener hardware all the time. 🙂

Although they may not fall out when you remove the Allan nuts, there is a thick washer underneath each of them. Try to get the washers out before you remove the timing cover so you don’t lose any when the cover comes off.

Remove Inner Timing Cover Without Special Tools

You can usually remove the inner timing cover without the need for any special tools. The trick is to heat the cover around the crankshaft seal with a heat gun (if you want to save the seal and reuse it) or you can use a torch if you are going to replace it.

Wearing my welding gloves, I can wiggle and pull the inner timing cover off without much trouble. The front main crankshaft seal stays in the cover and I’ll remove it later. There are some casting marks on the inside of the cover.

OPTIONAL-Cycle Works Timing Cover Removal Tool

If you can’t get the cover off, you can use the Cycle Works Stage II or Stage III engine tools as both contain a metal plate you can use to pull the cover off. I used to use the plate to remove the timing covers which came off very easily. So this time I used heat and my hands and it came off just as easily with less time spent putting the tool together.

Nonetheless, here is how the tool goes together to remove the inner timing cover.  Besides the parts from Cycle Works, you need to use the three alternator stator cover bolts to hold the plate to the timing cover.

As shown in the picture above there is a large aluminum plate, a puller bolt, a steel puller nose, and a small Allan bolt. The three alternator stator housing bolts are shown underneath the large aluminum plate.

As shown above, one side of the aluminum plate has a slot cut to accept the face of the steel puller nose. The other side of the aluminum plate is different as shown below.

As shown below the steel puller nose fits into the grooved side of the aluminum plate with the nose sticking out the other side.

Before I install the tool, I thread the small Allan bolt into the nose of the crankshaft taper to protect it from the puller bolt. I install the large aluminum plate with the steel puller nose on the crankshaft nose and then thread the large puller bolt into the puller nose.  I tighten the puller bolt to pull the inner timing cover off.

Tour Of Inside Of The Inner Timing Cover

Now the inner timing cover is off I can access the parts underneath it.

In the picture above, the inner timing cover gasket is stuck to the engine block. And there are two “doughnut” gaskets around the top top two cover bolts. But, there is no oil where the doughnut gaskets are. If you think of the cover gasket as a shim with a certain thickness, then in order for the cover to bolt to engine block evenly and uniformly to give an oil tight seal, the top two bolts through the cover need shims of the same thickness. Hence, the two doughnut shims.

At the bottom is the large diameter camshaft timing sprocket. There is a punch mark at the 12:00 position. When the engine is at top-dead-center (TDC), this punch mark will be either in the 12:00 or 6:00 position.

The reason it could be at either position is because the camshaft rotates one-half turn for every turn of the crankshaft. For that to happen, the camshaft sprocket is larger than the crankshaft sprocket; it is twice the diameter and has twice as many teeth as the crankshaft sprocket.

The crankshaft sprocket is behind the crankshaft nose bearing.

The timing chain in the 1983 engines is a single row chain whereas the earlier engines used a dual row chain. The chain uses a master link, which is very convenient, while the earlier dual row chains were continuous so you had to use a bolt cutter to cut the chain to remove it. The single row chain has a chain tensioner on the right and a slider on the left.

Remove Timing Chain

The crankshaft rotates clockwise (direction of the red arrow in the picture below) when viewed from the front of the engine. Consequently, the master link fish clip is installed so “the fish swims down stream”; the head of the fish clip points in the direction the chain moves.

I use needle nose pliers to remove the fish clip from the master link. I use a small screw driver to push the master link pin out of the chain. You could use a paper clip. Then I pull the timing chain out.

Remove Chain Tensioner and Slider

The chain tensioner arm slips over a pin secured by a circlip. I use a screw driver to push the circlip out of it’s groove and remove the timing chain tensioner.

There is a indentation where the tensioner piston pushes on the arm. The piston and it’s spring pop out of the sleeve the fit in as soon as I remove the tensioner arm.

The slider is secured with a nut and a bolt. I remove them. There is a wave washer under the nut and bolt and also there is a thick flat washer under the slider bracket on the stud and on the bolt.

The side of the slider that faces me has markings on it. That side also has a rounded profile of the cast rubber. There are no markings on the back side of the slider.

Remove Crankshaft Nose Bearing & Timing Chain Sprocket

I’m ready to remove the crankshaft nose bearing and timing sprocket.

I use the Cycle Works tool to remove them.

In addition to the parts shown in the picture above, I have put a couple layers of masking tape in the crankshaft taper to protect it from scratches. And, I install the small Allan bolt into the threaded hole in the crankshaft nose to protect the nose from the puller bolt.

The tool has a clam shell. Each half has a thick and thin shoulder. The thick shoulder goes up against the puller nose and the thin shoulder goes behind the crankshaft timing sprocket.

I put one half of the clam shell around the crankshaft sprocket and nose bearing being sure the thin ridge is behind the sprocket.

I insert the puller nose with the puller bolt partially threaded into it inside the clam shell half and install the second half so it’s behind the crankshaft sprocket and captures the puller body. Then I tighten the puller bolt until it’s snug at which point the clam shell halves will stay on the crankshaft sprocket.

I put some wheel bearing grease on the puller bolt threads and use two 1-1/8 inch box wrenches to tighten the puller bolt until I pull of the nose bearing and sprocket.

The nose bearing is made by FAG and is marked “16007A” and is a C3 tolerance.

The crankshaft timing sprocket fits on a key that is at the 9:00 position when the engine is at TDC. The teeth of the sprocket are off center. The wider side of the sleeve goes next to the engine block while the narrower side goes next to the nose bearing.

There is a spiral groove cut into the inside of the crankshaft timing sprocket hole. I checked with a knowledgeable BMW mechanic, Tom Cutter, of Rubber Chicken Racing Garage and he said “nothing to worry about”.