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Thread: 94 R1100RS Knock and Valve Train Noise

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    Registered User david.soley's Avatar
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    94 R1100RS Knock and Valve Train Noise

    I have a 1994 R1100 RS with 48,000 miles. Recently it felt like the throttle bodies were becoming out of sync. I had replaced the throttle cable in the beginning of the summer and assumed that the cables had stretched. It also was time for an oil and filter change.

    I changed the oil and did a quick sync, airscrews onlyt. The bike seemed to run a little smoother on my way to work. On the way home, however, it was back to running rough.

    Today I set the rocker arm sideplay adjustment to approximately 0.005", and confirmed that the intake valve was 0.012"freeplay and the exhaust valve freeplay was 0.014". The odd thing was that even though the plugs were removed it seemed difficult at near top dead center to turn the engine over using a wrench on the crank shaft. I assumed at the time that I was just fighting compressing the valve springs.

    Upon starting the bike up, it sounded like there was someone inside hammering on the side of the engine case with a ball peen hammer. The engine sounded nothing like it had when properly tuned up. It was VERY rattley sounded like there was no oil in it. The engine does not quiet down after running for long enough for the oil pressure to come up. It sounds like absolute CRAP, as if I give it any throttle or, god forbid, I ride it, I will be picking up wadded up parts after it violently comes apart.

    I have gone back through the valve train adjustment. The valves are set correctly and the rocker arm sideplay is correct. There is the proper amount of oil and it is circulating.

    I didn't make any other changes so why does the bike make the hammering noise? It almost sounds like there is a severe rod knock and that the auxilary drive shaft is loose or the auxilary drive shaft chain is stretched or loose.

    Has anyone experienced this? Where do I start short of assuming a rod bearing and tearing the entire engine down? I've done engine work on a succesful open wheel racing team and am comfortable doing the work and sure of my abilities. But this is the first oilhead I have worked on and this has me perplexed. How did it go from a seemingly simple throttle body out of balance is to knocking like a jack hammer sitting overnight. Help!

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    Benchwrenching PGlaves's Avatar
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    Sounds like a cam chain tensioner problem to me. If it has the original on the left side it should be replaced.

    I would also remove the left valve cover and shine a bright light down the cam chain tunnel to verify that the chain guides haven't broken. Look for tapered ends - if blunt something has broken.
    Paul Glaves - "Big Bend", Texas U.S.A
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    knock

    The transmission in the 1100s periodically make a goodly knocking sound. Does the noise go away, or at least change when you pull the clutch in?

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    Are you sure that you rotated the crank after you adjusted one side before doing the other?

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    Registered User david.soley's Avatar
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    Quote Originally Posted by PGlaves View Post
    Sounds like a cam chain tensioner problem to me. If it has the original on the left side it should be replaced.

    I would also remove the left valve cover and shine a bright light down the cam chain tunnel to verify that the chain guides haven't broken. Look for tapered ends - if blunt something has broken.
    Paul, thank you for replying. I follow your posts here on BMW MOA and your Bench Wrenching column in BMW On. Both have been very helpful.

    The cam chain tensioner is the new style and "loads" up from oil pressure shortly after starting as it should. I did check down both the left and right cam chain tunnels. Both chain guides are intack and appear in excellent condition.

    One thing I should mention, when I set the flywheel timing mark (OT) to top dead center, the arrows on the cam chain gear did not point straight out as described in the Oilhead Maintenance Manual by the Internet BMW Riders and Oilhead Riders on page 10, written by Carl Kulow, "Note: Also at OT, the arrow on the cam chain gear will be pointing straight out.ÔÇØ Instead both left and right pointed at about a 15 to 20 degree angle off from straight out.

    When I run the engine, the very loud and obnoxious chain noise sounds like it is coming from the auxillary drive shaft chain. I used the stethoscope method of isolating the location of the noise to the engine case.

    The loud knocking sound also seems to be coming from the engine case. It definitely is not clutch or transmission related. The noise is there whether the transmission is in 1st or neutral and also when the the clutch is engaged or disengaged.

    I've heard a few engines with rods knocking and this engine makes the same sound. I've been hoping against hope that it was something I am not familiar with or that I could be convinced it was something else. To best describe the noise would be to say that the knock is so metallic and so loud that I am afraid a hole will soon be hammered in the case if I allow it to run.

    Without knowing what the insides of the engine look like and how they relate to each other I'm kind of working blind. I was wondering if it was possible that the auxillary drive shaft chain is stretched and possible jumped a tooth allowing the auxillary drive shaft to become out-of-time with the crank shaft. This could explain the cam gear arrows not being straight out at TDC, the excessive chain noise from the engine case and the engine running somewhat poorly and out of sync. Could this also explain the knocking noise? Right now I'm afraid that I am going to need to pull the engine apart to find out.

    I absolutely love the bike and am quite depressed by this situation. I must say that reading about your wife's R1100RS was one of the deciding factors in my getting this bike. It too is red but is the RSL version. I am the third and last owner, short of my daughter inheriting it. So, any and all help and encouragement is appreciated.

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    Registered User david.soley's Avatar
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    Quote Originally Posted by flars View Post
    The transmission in the 1100s periodically make a goodly knocking sound. Does the noise go away, or at least change when you pull the clutch in?
    Definitely not transmission related. The knocking is present when the transmission is in both neutral and 1st and when the clutch is both engaged and disengaged. Careful "ear to the engine" work indicated that the knocking is within the engine case.

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    Registered User david.soley's Avatar
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    Quote Originally Posted by darkstar1 View Post
    Are you sure that you rotated the crank after you adjusted one side before doing the other?
    Double checked TDC on the initial valve adjustment and again after hearing the "racket" produced during running. Valves are adjusted correctly. If you can get beyond the loud chain noise and the horrendous knocking noise, the engine ran OK.

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    Quote Originally Posted by david.soley View Post
    Paul, thank you for replying. I follow your posts here on BMW MOA and your Bench Wrenching column in BMW On. Both have been very helpful.

    The cam chain tensioner is the new style and "loads" up from oil pressure shortly after starting as it should. .
    umm, the new style does not need to load up with oil to provide full tension. that was the issue with the old CMT- it rattled at startup because it required oil to "load up". the new one does not allow oil to drain out when sitting, so no load up time required, thus quiet at the start.
    check the size of the bolt head. new one is 15mm, old one is 17mm.
    Ride Safe, Ride Lots

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    Pointing Arrows --

    Quick, limited comment, as can't contribute to "what's wrong" here.

    My '94 R-RS arrow's don't point straight out either, but aren't as far off as yours are, apparently.

    Fortunately, my bike runs like a sewing-machine, but those arrows don't point straight out.

    Wonder whether others have had this experience?

    Walking Eagle

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    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by darkstar1 View Post
    Are you sure that you rotated the crank after you adjusted one side before doing the other?
    If you didn't, then you will get loud noises and maybe interference between a valve and piston - which could account for both the hard turning with plugs out and loud noises.
    Paul Glaves - "Big Bend", Texas U.S.A
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    My 94RS has a LOT more miles on it, and I have replaced the LH side tensioner about two years ago at 150k miles. Lately, when 1st starting the bike for the day I too notice a knocking sound that disappears after the engine warms up. I have recently checked the valve clearance and rocker tower clearance and all is in spec. I did also rotate the engine after checking the valve clearance on the LH side first.

    Since my bike has higher miles on it, I wonder if the RH tensioner may be weak and not offer enough cam chain tension until the oil pressure builds up. I am tempted to simply replace the RH tensioner to see what results I get. I may also take the valve covers off to check the cam chain guides for what I can see in the chain galleys.

    I have noticed too, I get a buzzing, not quite rattle, from the engine when I rev it up through 4,000 to 5,000 rpm. Moreso again when just starting out for the day.

    Other than that, the bike runs great, is smooth through the power band, gets an average of 45mpg, doesn't use oil, no weird vibes. So unless this is something more serious I expect to get 200,000 out of my good ol RS.

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    Quote Originally Posted by david.soley View Post
    Today I set the rocker arm sideplay adjustment to approximately 0.005", and confirmed that the intake valve was 0.012"freeplay and the exhaust valve freeplay was 0.014". The odd thing was that even though the plugs were removed it seemed difficult at near top dead center to turn the engine over using a wrench on the crank shaft....

    Upon starting the bike up, it sounded like there was someone inside hammering on the side of the engine case with a ball peen hammer.
    As Mr. Glaves has pointed out, I think these events are related. Your bike wasn't making noise before you worked on it. Now it is. I sincerely hope I'm wrong but I'm thinking valve/piston interference issues.
    Last edited by BC1100S; 08-28-2012 at 04:28 PM.

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    Registered User david.soley's Avatar
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    Quote Originally Posted by PGlaves View Post
    If you didn't, then you will get loud noises and maybe interference between a valve and piston - which could account for both the hard turning with plugs out and loud noises.
    I did not adjust the valves, I confirmed that the lash was set correctly.

    Also, if the valves were adjusted to 0.012" clearance on intake and 0.014" clearance on exhaust at anywhere other than TDC of the compression stroke, they would not fully open when the lobe of the cam pushed them open and there would not be an interference condition.

    In the case of adjusting the valves at any point other than TDC of the compression stroke the engine would not breathe properly and would most likely have a very poor idle and poor throttle responce. The engine runs fairly well other than the excessive chain noise and loud knocking both coming from the engine crank case.

    The knocking is what has me very concerned. It too is coming from within the engine crank case. It should be noted that with the sparkplugs removed and the engine turned over there is no noticeable knock. Neither the sparkplugs nor the piston show signs of impact. The audible rod knock occures when the engine is running.

    The bike/engine was developing a severe vibration prior to the oil change and valve lash confirmation. There did seem to be excessive chain noise, in my opinion, coming from the engine crank case but those posts I've read and other oilhead owners I've talked to have said that chain noise is typical of this engine.

    I don't think the two events, the knocking and my checking valve lash, are related, in fact I believe that had I ridden the bike another day or two before working on it the knocking would have become apparent outside of my garage, possibly catastrophically, for the engine at least, at 70mph.
    Last edited by david.soley; 08-28-2012 at 07:03 PM.

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    Registered User david.soley's Avatar
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    Quote Originally Posted by bikerfish1100 View Post
    umm, the new style does not need to load up with oil to provide full tension. that was the issue with the old CMT- it rattled at startup because it required oil to "load up". the new one does not allow oil to drain out when sitting, so no load up time required, thus quiet at the start.
    check the size of the bolt head. new one is 15mm, old one is 17mm.
    The engine does appear to have the new style tensioner installed. The bolt head size is 15mm. I measured it but I may be wrong so I will measure it again. But, it also has a spring in it. So after running for about 5 or 10 seconds the tensioner does load up with oil.

    Whether it has the old or the new cam chain tensioner seems to be besides the point though as the chain noise is not coming from either of the cam chains in the rear of the engine, but is coming from the area of the auxillary drive shaft chain in the front of the engine.

    The knocking is what has me very concerned. It too is coming from within the engine crank case. It should be noted that with the sparkplugs removed and the engine turned over there is no noticeable knock. Neither the sparkplugs nor the piston show signs of impact. The audible rod knock occures when the engine is running.

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    About the only way you'd know this, " Neither the sparkplugs nor the piston show signs of impact.", would be to remove the heads or look into the spark pug hole with a boroscope.

    Unless the spark plug is the wrong threaded length, it cannot contact the piston at any timing condition in the engine. However, the valves can contact the piston if not timed/adjusted properly. Contact again would be difficult to see without remoing the heads. If contact did occur, it would likely be near the outer diameter of the piston, nothing you could see through the spark plug hole.

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