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New Defective Clutch Housing Cover K1200LT

saddleman

Enjoy The Ride
After 180,000 miles it was time for my first clutch replacement. I had bought the parts over a year ago & never opened any of the boxes until Christmas day. I had planned on having the clutch done while I had a few days off for the holidays. The housing cover had severe chatter marks in several places in the clutch disc area. My local dealer did get me a replacement but because of the holidays I didn't get it until Tuesday.

I'm not complaining one bit I just want to show others what to look for. I have been a mechanic & machinist since 1970 & should have inspected the parts when I bought them. 180,000 Miles 003.jpg
 
This is what they should look like. This also would be for any dry clutch system housing cover or pressure plate.180,000 Miles 025.jpg
 
The reason I only said LT's is because it applies to all of the LT models & years.

Not true. That clutch housing cover is unique to K1200LT ONLY. It will not fit K100LT or K1100LT.

The K1200LT clutch housing cover has 2 1/2 times the mass of ANY of the other Flying Brick clutch housing and has a noticeably different appearance. The center hole in all non-K1200LT covers is much larger.

You are correct in suggesting that NO clutch housing cover should have the machining marks shown on your first cover.


:dance:dance:dance
 
It actually applies to any dry clutch BMW manufactured since 1923.
I'm sure you are correct Paul. I'm only familiar with the LT's & this is not about a particular model or year of bike anyway but about the bad machining of the clutch disc surface area.
 
For a non-machinist, it only appears to me to be a dirty/oily first unit or perhaps even a poor digital reproduction? Perhaps a more detailed description of what you see as bad and where it is, along with more generic applicability info, might have been the ticket for Lee to see why you felt you did not need to be more bike specific. After the other comments, I can only assume the swirly stuff is not a digital thing and must be machine marks, the other stuff looks like oil spots, is that rust or something else? Obviously the second photo looks much better, but to a novice, looks like it could have just been the first one cleaned up and the camera held at a different angle. I interpret now that it is way better and others can see that better than I can because they know what to look for and I don't.....:wave
 
Machining chatter is a harmonic imbalance between the cutting tool & the workpiece. It happens when the two bounce against each other during the machining process. There are many different causes for this to many to list here. On this clutch housing it started in the center & kept getting worse as it was being machined towards the outside.

This housing I have had for almost two years & has some slight surface rust on it even though I had never opened the box & it was still sealed in the plastic bag. I get quite a few BMW parts new that have slight rust on them especially the shims for the crown bearings for final drives that I rebuild. Here is a closer pic. of the chatter.180,000 Miles 005.jpg
 
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I'm sure you are correct Paul. I'm only familiar with the LT's & this is not about a particular model or year of bike anyway but about the bad machining of the clutch disc surface area.

The point I was trying to make (in post # 6) was that such a machining defect, leaving chatter marks on a clutch surface that is supposed to be smooth, would affect any dry clutch cover or pressure plate. Anybody rebuilding the clutch on any dry clutch equipped motorcycle ought to look for and notice such a defect if present.

I think such a defect is very unlikely if a human is actually operating and watching the machining process, but is more likely the result of fully automated machining with one human somewhere with a panel operating one or more machines by remote control.
 
Thanks

Saddleman,
Thanks for the additional information and the close up. I can clearly see what you describe and can understand why it is an issue as well as how it likely happens. Now knowing this is not how they should be, I will be able to spot it and know it is a bad thing.
Thanks again.
 
Machining chatter is a harmonic imbalance between the cutting tool & the workpiece. It happens when the two bounce against each other during the machining process. There are many different causes for this to many to list here. On this clutch housing it started in the center & kept getting worse as it was being machined towards the outside.

This housing I have had for almost two years & has some slight surface rust on it even though I had never opened the box & it was still sealed in the plastic bag. I get quite a few BMW parts new that have slight rust on them especially the shims for the crown bearings for final drives that I rebuild. Here is a closer pic. of the chatter.View attachment 43026

That looks like what happens when the tool hits a hard spot and the tip fails. Hard spots are common in china and india castings. That said, if it is flat, should burnish right up and be ok.

Rod
 
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