- Preparation For Crankshaft Sprocket and Nose Bearing Install
- How To Assemble The Cycle Works Tool
- Install Crankshaft Sprocket
- Install Crankshaft Nose Bearing
- Install Timing Chain with Master Link
- Replace Front Main Seal
- Install Inner Timing Cover
Considering the age of the bike and the mileage, I am replacing the crankshaft timing chain sprocket, the crankshaft nose bearing, the timing chain and the front main seal along with the timing cover gaskets. I’ve replaced these components on early engines that use the dual-row timing chain and the procedure is the same for the later single row chain that is used on this engine.
I did the same work on earlier bikes and you can read about that work using the links below. The R75/6 procedure includes a list of resources about how to do this work that is informative.
- 11 BMW 1975 R75/6 Replace Timing Chain, Crankshaft Sprocket, Nose Bearing
- 11 BMW 1977 R100RS Replace Timing Chain, Crankshaft Timing Gear & Nose Bearing
This 1983 RS does not have the mechanical points the other two earlier bikes use, nor the mechanical tachometer. It has a “bean can” with electronic points (aka, Hall sensors) inside and has an electronic tachometer. Therefore there is no camshaft seal or tachometer drive seal in the inner timing cover to replace. The bean can uses an O-ring for an oil seal. I show installation of the bean can in a separate article on installing the ignition system.
I have the Cycle Works tools that can be assembled to push the crankshaft timing sprocket and crankshaft nose bearing onto the crankshaft. That said, in the past I did not need to use the tools to install the crankshaft timing sprocket, but I always needed them to install the nose bearing.
I install the following new parts.
The gaskets and seal are in the EME engine gasket and seal kit I bought, but I also show the BMW part number for the individual gaskets and seal in the table below.
|11 21 1 335 586||SPROCKET (from 09/78)||1|
|07 11 9 981 722||GROOVED BALL BEARING – 160 07||1|
|11 31 1 335 580||TIMING CHAIN||1|
|11 31 1 338 185||CHAIN TENSIONER||1|
|11 31 1 335 576||SLIDE RAIL||1|
|11 31 1 335 584||COIL SPRING||1|
|11 31 1 335 579||PISTON||1|
|11 14 1 337 654||SHAFT SEAL – 28X47X7, [EME Gasket Kit]||1|
|11 14 1 338 428||GASKET, [EME Gasket Kit]||1|
|11 14 1 338 429||WASHER-GASKET, [EME Gasket Kit]||2|
I shot three short videos summarizing how I do this work.
VIDEO: 1983 BMW R100RS Install Crankshaft Sprocket and Nose Bearing
VIDEO: 1983 BMW R100RS Install Timing Chain
VIDEO: 1983 BMW R100RS Install Inner Timing Cover
Preparation For Crankshaft Sprocket and Nose Bearing Install
This is where I start from. I put masking tape on the taper of the crankshaft nose to protect it from getting nicked.
There is some preparation to do before installing these parts. I apply several layers of masking tape on the tapered section of the crankshaft nose to protect it from getting scratched when I install the crankshaft sprocket and the nose bearing.
I prepare the crankshaft sprocket. Sometimes there are burrs on the edge of the keyway. The keyway slides over the Woodruff key on the crankshaft journal. A burr will impede installation of the sprocket. I use a small file to dress the front and rear keyway edges to remove any burrs.
There is a mark stamped at the root of one tooth of the crankshaft timing sprocket. It’s an index mark used to align the crankshaft with the camshaft so the valve timing is correct. However, when the nose bearing is installed, it is very hard to see the index mark. I put white paint on the face of the tooth underneath the mark so I can see it when I install the timing chain.
There are two shoulders on the crankshaft sprocket, one longer than the other. The long shoulder points toward the engine block and sits against the face of the crankshaft. To be sure I don’t inadvertently install the sprocket backwards, I use a Sharpie to put an arrow on the wider shoulder to remind me which direction to install the crankshaft timing sprocket in.
I clean the journal the crankshaft timing sprocket and nose bearing slide onto with metal polish to remove any crud and I got quite a bit off it.
After cleaning the crankshaft sprocket journal, I put lubricant on it so the timing chain sprocket will slide on easier. I like to use lard. It’s a good lubricant for assembling heat shrink steel parts.
Lard is made from pork fat, and as we know from years of experience, everything goes better with bacon. 🙂
How To Assemble The Cycle Works Tool
The pusher bolt has a smaller diameter threaded nose that screws into the threaded hole in the front of the crankshaft nose. A “sandwich” of two large flat washers with a needle bearing plate in between slides over the larger threads of the bolt.
The needle bearing plate goes between the two large washers to let the nut on the pusher bolt turn easily.
The sleeve has two different faces. One face has a shoulder machined part way inside the sleeve. This lets the short shoulder of the crankshaft sprocket slide inside the sleeve.
The other face does not have a shoulder inside and is placed against the inner race of the nose bearing. When force from the pusher bolt is applied to the inner race, it does not damage the bearing. But if the force is applied to the outer race, it will destroy the bearing.
The pusher bolt slides inside a pusher nose. The nose butts up against the sleeve to push the sprocket, or the nose bearing, onto the crankshaft journal. The thread on the nose of the pusher bolt screws into the thread in the crankshaft nose. Tightening the large nut pushes the sprocket or bearing onto the journal bearing.
Install Crankshaft Sprocket
I put the crankshaft sprocket and the nose bearing in the oven to heat them to 350 F. It takes about 30-40 mins for the sprocket to heat up.
In the past, I’ve been able to install the crankshaft sprocket by just pushing it on the crankshaft journal and did not need the Cycle Works tool. But, I put the sprocket into the sleeve of the tool before heating it so if I have to use the Cycle works tool, I just need to install the pusher bolt and pusher nose to push it on.
When it is hot, I put on my welding gloves, take it out of the oven and quickly put it on the crankshaft nose. I align the keyway of the sprocket with the Woodruff key in the crankshaft and slide the sprocket all the way on the crankshaft shoulder. It slides on very on easily.. I hold it tight against the shoulder for 30 seconds until it cools enough to stay put.
Install Crankshaft Nose Bearing
It maybe easier to install the master link in the timing chain if you don’t have the nose bearing installed. You can install the nose bearing after installing the timing chain if you wish.
Before I take the heated nose bearing out of the oven and place it on the crankshaft nose, I add a little more lard as the crankshaft timing sprocket scraped it off. However, as in the past, it does not want to slide onto the crankshaft journal.
I screw the assembled Cycle Works pusher tool into the threaded hole in the nose of the crankshaft. Then I use two crescent wrenches, one holding the pusher nose and the other on the nut, and tighten the nut to push the nose bearing onto the crankshaft journal until it butts up against the face of the sprocket and won’t go any further.
I visually inspect the sprocket to ensure it is flush with the face of the crankshaft journal and that the nose bearing is flush with the face of the sprocket.
Install Timing Chain with Master Link
Before starting to install the new timing chain, I tape over the hole in the front bearing carrier. This hole loves to eat master links and when installing a new master link you will drop it several times. If it goes through the hole, you can fish it out of the oil pan with a magnet, but that’s a pain to do. So, an ounce of prevention is called for.
Install Timing Chain Tensioner
I have to install the timing chain tensioner before installing the timing chain as the tensioner nose and spring cannot be installed into the sleeve on the right side of the front bearing carrier when the timing chain is installed. I insert one end of the spring into the nose and then push the other end into the sleeve in the front bearing carrier. I compress the spring and then slide the follower into the sleeve. While holding the follower in the sleeve, I insert the follower arm on the pin and release the follower.
Since the follower arm will be in the way of the chain, I use a small vice grip to clamp it all the way back against the casting so it is out of the way.
Then I install the E-clip on the pin to secure the tensioner arm.
Orient Crankshaft And Camshaft Index Marks
I position the flywheel at top-dead-center (TDC) so the “OT” mark is aligned with the reference mark in the left side of the timing hole in the engine block.
I check that the crankshaft tooth that I put white paint on is at 6:00. I rotate the camshaft sprocket so the punch mark that I put a white paint dot on top of is directly opposite the white crankshaft tooth. This is the correct orientation of the crankshaft and camshaft at TDC: the tooth of the crankshaft points to the valley between two teeth on the camshaft.
Position Timing Chain On Sprockets
I use a small Phillips head screwdriver that fits inside the hole on the end of the chain to snake the chain over the crankshaft sprocket teeth. I move it far enough over the crankshaft sprocket so the end of the chain reaches a middle tooth on the camshaft sprocket. Then I wrap the other end of the chain over the camshaft sprocket from the other side so the ends are next to each other on adjacent teeth.
Install Master Link
I insert the old master link part way into the front of the chain ends to keep them together. Then I rotate the crankshaft to move the master link to the left side of the crankshaft sprocket. I want to install the new master link from the back side of the chain so I can put the fish plate and fish clip on the front of the chain. However, there is not enough room to insert the master link where the camshaft sprocket passes in front of the engine block. There is enough room beside the crankshaft sprocket to insert the master link.
I use long, thin needle nose pliers to insert the master link. I grip one leg of the link butting the end of the pliers against the plate and tip the link at an angle. This orientation allows me to position the pins of the master link perpendicular to the holes in each end of the chain and pull it part way into the hole. This is tricky to do and I have to reorient the master link in the pliers several times. I find once I get one pin of the master link to just enter a hole, I can put a finger on the link and guide the other pin into the other hole so it slides in a little bit. This takes patience and is easier to do if you are sitting in a chair in front of the engine so your body is relaxed.
I rotate the chain until the old master link in the front of the chain is past the nose bearing. Then I use a small screwdriver to push the new master link into the holes from the rear, while at the same time with the other hand, I pull out the old link.
I rotate the chain further so the master link is in front of the engine block on the side of the camshaft chain. This prevents the master link from coming out of the ends of the chain as I install the fish plate and the fish clip.
The fish clip orientation is important. It has a head and a tail. The saying is, “The fish swims downstream”. That means the head of the fish plate points in the direction the chain rotates. The crankshaft turns clockwise so the timing chain does as well. When I have the fish plate oriented the correct direction on the grooves of the master link pins, I use needle nose pliers with one jaw on the head of the clip and the other on the pin next to the tail of the clip and squeeze the pliers until I snap the pin tight into the grooves.
Once I have the fish clip installed, I rotate the crankshaft to verify that the index marks on the crankshaft sprocket and camshaft sprocket are still opposite each other. I want to be absolutely sure I didn’t inadvertently install the timing chain one tooth off from where it belongs when I was snaking the chain over the crankshaft sprocket and camshaft sprocket teeth.
Install Rubbing Block
The rubbing block is installed on the opposite side to the timing chain tensioner. The side of the rubbing block that faces you has a curved profile of rubber where it meets the steel arm.
The rubbing block has two holes and mounts on a lower stud with an upper bolt. The hardware consists of a thick flat washer that goes against the face of the hole in the front bearing carrier, then the rubbing block arm, followed by a wave washer and then either the nut (lower) or the bolt (upper).
I position the block so it touches the chain but I don’t push it hard into the chain, I just butt it up against the chain. I torque the bolt and nut to 15 FT-Lbs.
The timing chain, chain tensioner and rubbing block are installed. Next up is installing the inner timing cover.
Replace Front Main Seal
I cleaned up the inner timing cover and repaired the damage to the paint using gloss black engine paint which is rated up to 500 F. Before I install the inner timing cover, I replace the old front main seal. I use a large socket and a plastic hammer to drive out the old seal.
The old seal leaves some rubber bits on the edge of the hole in the inner timing cover. I use 600 wet/dry sand paper to remove this and use it to clean the edges of the boss the nose bearing fits into.
I put a couple drops of engine oil on the edge of the new front main seal and smear the oil around the entire edge to lubricate the seal and make it easier to install. I heat around the hole the seal fits into with a heat gun and then press the seal into the hole with my fingers. The seal should not be proud of the front or rear of the hole. It’s easier to get the seal flush by checking the back side of the hole.
Install Inner Timing Cover
There are several preparation steps to complete before I install the inner timing cover
Assemble Cycle Works Inner Timing Cover Tool
I have had good luck being able to push the heated timing cover over the nose bearing without using the Cycle Works tool to push it on. But, I like to use the tool to press on the cover while it cools so the nose bearing stays put in the boss.
But first, I replace the old masking tape and locate the new tape about 1/2″+ away from the face of the nose bearing. The inner timing cover will cover the back edge of the tape when it’s installed and I won’t be able to get it off the taper of the crankshaft nose.
Here are the Cycle Works tool parts I assemble to push the inner timing cover against the engine block while the timing cover cools down so I am sure the nose bearing is against the boss in the inner timing cover.
If the nose bearing is not all the way against the boss on the inside of the inner timing cover when the cover cools, the inner timing cover will push the captive nose bearing to the rear and the crankshaft be pushed up against the inside thrust washer which will bind the crankshaft and keep it from turning easily. That’s why I like to use the Cycle Works tool while the inner timing cover cools.
In the picture below, left to right, is the puller nose, the puller plate and the pusher bolt with the two flat washers and the needle bearing plate in between them.
In this application, the recess in the aluminum plate that the pusher nose fits into faces outward so the pusher bolt will push the plate against the inner timing cover.
Here are the parts assembled for pushing the inner timing cover against the engine block.
This is how the Cycle Works tool goes on the crankshaft, but without the timing cover in place. The small threaded nose of the pusher bolt threads into the taped hole in the crankshaft nose.
Install Inner Timing Cover Gaskets
The inner timing cover has three gaskets; a large one and two small doughnuts.
The two doughnut gaskets go around the two top holes of the timing cover into the top of the engine block on each side.
Before I install the large gasket, I need to clean all oil off the sealing surface on the engine block and the timing cover sealing surfaces. The gasket has a heat activated adhesive and any oil will interfere with the gasket seal allowing oil to leak past it. I use alcohol wipes to clean the surfaces. I keep wiping with new wipes until I get a wipe that shows no discoloration.
The gasket mounts one way with the large tab on the left side of the engine block as shown below. I put some axle grease on the two doughnut gaskets to keep them in place around the two top bolt holes in the engine block.
Heat Inner Timing Cover
I heat the timing cover to 275 F in the oven for about 30 minutes. I also put some lard on the outside of the nose bearing so the bearing will slide easily into the boss in the inner timing cover. You can use oil, but I like lard for this application.
I remove the masking tape I applied to keep the master link from falling into the oil pan.
I left the tape in place when I first installed the timing cover because I was not staying focused on the work. This is a good lesson for me, and you. Concentrate on what you are doing and don’t get distracted so you don’t make careless mistakes like this that cause you to have to undo your work and redo it again … unless you need the practice 🙂
Install Inner Timing Cover Over Nose Bearing
When the cover is hot, I pull it out of the oven and it presses on over the nose bearing easily. I attach the Cycle Works tool and tighten the nut finger tight to hold the timing cover tight against the engine block.
With a flash light, I visually inspect the location of the two doughnut gaskets to ensure they have not moved. They hadn’t so I insert the two top bolts and finger tighten them to ensure the gaskets don’t get displaced.
I visually inspect the edge of the cover to ensure it’s uniformly tight against the engine block.
Align Bean Can Hole with Camshaft Center
The O-ring on the bean can seals better if the bean can hole is centered on the camshaft center line. There is enough free play in the inner timing cover mounting bolts to allow the bottom of the cover to be off-center.
I have the top two inner timing cover bolts finger tight. I use a 4 mm bolt as a gauge block to measure the distance between the inside of the bean can hole and the outside of the flange on the camshaft.
I walk the bolt around the perimeter of the bean can hole. If the cover is centered, the edge of the bolt will just touch the outside edge of the flange all the way around the bean can hole. If the cover is off center, I use a rubber mallet and lightly tap the lower edge of the cover to get it centered. In this case, my cover is centered. I hand tighten the bolts and nuts and wait for the inner timing cover to cool to room temperature.
Torque Inner Timing Cover Bolts & Nuts
I use my “Bingo card” of bolts and nuts that I inserted them into when I removed them. I use the card to be sure I install all the hardware.
I install the nine bolts and three Allen nuts loosely into the cover. There are thick flat washers under all the bolts and under the nuts (note the three washers taped to the fight side of the Bingo card). Note that the head of the Allan washer is larger than the head of the Allan bolts.
I use thin needle nose pliers to insert the Allen nut washers on the studs. I use an Allan socket to tighten the nuts and bolts finger tight, and then back them of just a bit.
After the inner timing cover has cooled, I torque the bolts and nuts in three stages: 35 INCH-Lbs, 70 INCH-Lbs and finally, 72 INCH-Lbs.
The torque is in INCH not foot pounds. You need to use an INCH-pound torque wrench.
I torque them in a cross-wise pattern so I don’t deform the gasket.
Before I torque the bolts and nuts to the finally 72 INCH-Lbs, I use a heat gun and heat around the front main seal until it is hot to the touch. This ensures the nose bearing a bit loose in the boss and the final torque should ensure the bearing is fully seated in the boss.
After I finish torquing the bolts, I use a belt and suspenders method to verify that the inner timing cover is correctly installed. I insert a feeler gauge in the small gap between the inner timing cover and the engine block which is between the top bolt and the top Allan nut on each side of the timing cover. There should be a uniform gap between these fasteners. This is a way to verify that the cover is uniformly tight against the engine block and nothing is interfering with it.
There is not change in the gap on either side. The inner timing cover is successfully installed.
2020-01-19 Add caution to remove masking tape. Update inner timing cover video