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Old 05-15-2011, 07:00 PM   #46
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Originally Posted by supershaft View Post
From what I can tell, I think a lifter that is in your bike and not pitting has just as good or better chance of not pitting in the future versus a new one.
Bingo.
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Old 05-15-2011, 07:20 PM   #47
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I have not read ever post so some of what I am about to say may have already been covered.

Crank & cam cam gear-Leave them and replace the chain. You will loose about 10% of the life of the chain by not replacing the gears.

Replacing the cam. Pull one rocker arm one at a time, remove the rocker blocks and slide them back over the studs and re-torque the heads at 20 fp. This will keep from breaking the seal. Once you have the rocker arms and the push rods removed you can use a magnet to get the followers out of the way to slide the cam out and back in with out breaking the seal between the cylinders and block or the cylinders and heads.
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Old 05-15-2011, 10:58 PM   #48
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Originally Posted by supershaft View Post
From what I can tell, I think a lifter that is in your bike and not pitting has just as good or better chance of not pitting in the future versus a new one.
I'm sure that is very true, but for how long?

The flaking I have seen on airhead lifters sure appears to be plating that has worn thin and started flaking off.
Do you have another explanation for the flaking that occurs?
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Old 05-15-2011, 11:24 PM   #49
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I usually call it flaking too versus pitting. Some lifters will last a lot longer than any top end and then maybe through another top end while others won't last 20,000 miles before they start flaking. I have had real good luck sticking with the field tested and just replacing the ones that have failed the test.

Our type of lifter has always had flaking issues in all different kinds of engines every since they started being used until today. I am sure there is a bunch of reading on the subject in the SAE. Whatever causes it, no one has found a way to stop it. It's definitely not wear related since virtually brand new ones are just as likely to flake if not more so than ones with high miles. I suspect it's in the heat treating.
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Old 05-16-2011, 07:45 AM   #50
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Originally Posted by bmweuro View Post
Crank & cam cam gear-Leave them and replace the chain. You will loose about 10% of the life of the chain by not replacing the gears.
Can't agree with that, Chris.

A visibly worn crank timing gear should be replaced if you're fitting a new timing chain. It's simple to do and not terribly expensive.

No good reason to leave it in there.
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Old 05-16-2011, 11:12 AM   #51
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Can't agree with that, Chris.

A visibly worn crank timing gear should be replaced if you're fitting a new timing chain. It's simple to do and not terribly expensive.

No good reason to leave it in there.
500,000+ on BMW motorcycles and I have done at least 10 timing chains plus customers bikes never replacing the gears unless they were really really bad.
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Old 05-16-2011, 11:36 AM   #52
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Originally Posted by bmweuro View Post
500,000+ on BMW motorcycles and I have done at least 10 timing chains plus customers bikes never replacing the gears unless they were really really bad.
Well, Sir, in your esteemed and experienced opinion is this really bad?



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Old 05-16-2011, 11:46 AM   #53
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In my experience, a sprocket worn about as much as the one in Rob's photo will shorten the life of the chain by about 30 to 50%.

Maybe the big diff in our experiences revolves around what a worn chain is? You could probably get another 60k miles out of a chain that I call worn out if you don't mind your bike making a lot of noise, running like crap, and chewing itself up.
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Old 05-16-2011, 11:59 AM   #54
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Laugh POism

...INTERESTING READ....(caps off)

2 reasons I'm doing this,
(1) The leaking timing cover
(2) The jumpity timing mark when I look in there with a timing light.

I'm convinced that the PO(s?) F'd around with this bike in a less than knowledgable if not hamfisted manner.
God help me when I have to look inside the driveline...
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Old 05-16-2011, 04:57 PM   #55
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Well, Sir, in your esteemed and experienced opinion is this really bad?



Questionable. If you look at where the chain is actually wearing on the sprocket one might think you could run it. I would have to flip a coin on that one unless it was a customers bike then I would replace it.
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Old 05-16-2011, 08:20 PM   #56
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Questionable.
Here's a question: So why didn't BMW provide a spec for a worn chain or timing sprocket (per Clymers)?

It seems that we're entirely on our own when a fairly simple gauge (for sprockets) or spec for chain length could be provided (even bicyclists seem to have invented better guidelines for replacing these components).

Certainly, symptoms (noise, shaky timing marks, etc.) can indicate a need for a replacement but specs would help.

Just curious if anyone has any insights.
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Old 05-16-2011, 09:48 PM   #57
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The shaky timing marks and slapping sound are enough for me to take it apart and see what all it needs, besides a chain. I belong to the school that believes a worn sprocket like yours, has a big effect on the life of a chain.
I have spent most of 40 years around heavy equipment with tracks on it. The chain and sprockets in those undercarriages are basically the same as your timing chain and sprockets only larger. I know the effects of wear on all the various parts. They are not hidden from view, so I can feel, see and hear the parts as they eat themselves up when they don't fit together like they once did. It is not a pretty sound or a smooth ride.

If you think about the jerky rough ride of the tractor with the worn drive parts, it is the kind of ride (drive) your valves and ignition is getting, if the chain and sprockets don't fit together like they should.
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Old 05-16-2011, 11:01 PM   #58
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Originally Posted by fishkens View Post
Here's a question: So why didn't BMW provide a spec for a worn chain or timing sprocket (per Clymers)?

It seems that we're entirely on our own when a fairly simple gauge (for sprockets) or spec for chain length could be provided (even bicyclists seem to have invented better guidelines for replacing these components).

Certainly, symptoms (noise, shaky timing marks, etc.) can indicate a need for a replacement but specs would help.

Just curious if anyone has any insights.
Probably because BMW say replace them every time.
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Old 05-16-2011, 11:07 PM   #59
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Originally Posted by supershaft View Post
In my experience, a sprocket worn about as much as the one in Rob's photo will shorten the life of the chain by about 30 to 50%.

Maybe the big diff in our experiences revolves around what a worn chain is? You could probably get another 60k miles out of a chain that I call worn out if you don't mind your bike making a lot of noise, running like crap, and chewing itself up.
60k is a lot compared to 70k- 90k for a new one. The running like crap, noise and chewing itself up only comes from a badly worn chain not from worn gears.

With all of this said ride it for 6 to 10 years and worry about it later unless your putting 20k a year on your bike,
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Old 05-17-2011, 08:05 AM   #60
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...I gotta agree with Euro's philosophy. I'll be ridin' a walker by the time this bike needs another chain. However, I'm going to do the crank gear to help mitigate the winky timing mark.

That said, Rusty at MAXBMW sez it's BMW shop practice to replace everything to deter customers having to come back to have it done again.
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