The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Aethelric on June 10, 2020, 08:14:45 AM
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I could hear a noise from the engine which sounded like a chain rattling so I replaced the cam chain and tensioners. There did not seem to be anything wrong with the old ones.
I took it for a ride and the noise was still there.
When I got home and stopped the engine there was a clatter. When I tried to start it again the starter turned but not the engine.
So, suspecting the starter I took it off. It was fine.
BUT the flywheel was loose and turning freely and is obviously disconnected from the crankshaft.
I am in the middle of stripping it down to find the problem using nhmaf's excellent PDF on clutch removal.
Not sure what I'll find when I'm down to taking off the clutch, and I see there are all sorts of warnings about blocking the crankshaft when removing the flywheel. I haven't found anything on self detaching flywheels though.
Has anyone else come across this?
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I don't recall hearing of this problem before. Either the flywheel bolts came out or they sheared. There is confusion about torquing the flywheel bolts with some incorrrect published information resulting in excessive torque on the smaller size of bolt so shearing is a possibility.
Sometimes published torque settings have to be tested against common sense on what a particular bolt size can be expected to take.
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The bike has done 46000 miles, about 26,000 by me. I have never been in there before, and I'm guess I will be the first person to lay eyes the flywheel since the bike was built in around 1984.
I recently rebuilt the bike which had stood for around 10 years but did not get as far as removing the clutch.
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I think what you have going on is the starter ring is slipping on the fly wheel. Haven’t really look at the fly wheels on our bikes but I think they are built in two pieces. I have changed the ring gear on aircraft fly wheels. They are just a pressed on close tolerance fit. Heat the ring gear to have expand an slip over he fly wheel. I have had the ring gear spin on my Yamaha wave runner one time.
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You may well be right, thinking about it when I moved the bit I could see it did not seem heavy enough to be a flywheel.
That would be better as it means that I can take all the precautions when replacing the flywheel.
I should be in there in a day or too.
You have cheered me up :) Thank you.
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The ring gear has indeed become detached from the flywheel. It seems to be held on by six rivets which have sheared.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fphoto-electric.com%2Fimages%2Fring-gear.jpg&hash=f74c9b5d448b95258b8412d5b39c1532076b23e3)
Now waiting for parts, including the flywheel, to fix it. So glad I don't have to get in there and re-seat the shims.
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I'm surprised by the amount of metal flakes around the starter opening.
Could it be that the starter motor has the wrong number of teeth ? Or was not meshing properly on the flywheel rim ?
Or was the wrong type altogether ?
I saw a lot of crud but not that much metal on mine when I went there ...
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I'm surprised by the amount of metal flakes around the starter opening.
Could it be that the starter motor has the wrong number of teeth ? Or was not meshing properly on the flywheel rim ?
Or was the wrong type altogether ?
I saw a lot of crud but not that much metal on mine when I went there ...
The ring gear has detached from the flywheel and was free to rattle about and has taken a little of the casing away. The starter seems fine.
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Do you know you need to block the crank from sliding forward before removing the flywheel
Also the fly wheel can go on multiple ways
So you need to set it to OT before removing it and then put the new one on with the OT marks lined up Without disturbing the crank
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Thanks.
Yes, I originally thought the entire flywheel had become detached, in which case the crank would have moved.
The engine is now set to TDC and I am waiting for flywheel, stretch bolts and clutch let down bolts etc to arrive (in about a week).
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I’ve had my clutch out this week to do the rear main seal and oil pump o ring and my bike has pretty clearly suffered the same issue at some point - you can see the ring gear score marks on the case at the bottom of this photo.
The clutch holding tool was a 10 minute job to knock up, but it’s a virtual necessity when getting 125nm of torque on those flywheel bolts.
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*Flywheel holding tool!
The ‘81 and later clutch just backs straight off btw, rather than having to relieve the pressure, as on earlier models.
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*Flywheel holding tool!
The ‘81 and later clutch just backs straight off btw, rather than having to relieve the pressure, as on earlier models.
Oh, I did not know that. I could have been in there instead of waiting for the clutch lowering bolts. I'll be in tomorrow.
Thank you. :)
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Here is the problem
This is the flywheel:-
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.photo-electric.com%2Fimages%2Fflywheel_1.jpg&hash=5168f011aa05f90b755eb54d9c8cdaf6399d623f)
Looks OK, but theses bits are not supposed to come apart.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.photo-electric.com%2Fimages%2Fflywheel_2.jpg&hash=45d117b58501db4047fe3f09e782d88c444e2bf9)
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This might help:
http://www.bmwr65.org/YaBB2.612/cgi-bin/yabb2/YaBB.pl?num=1446449519
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This might help:
http://www.bmwr65.org/YaBB2.612/cgi-bin/yabb2/YaBB.pl?num=1446449519
Thanks for that. So it's rare but not unknown.
I'm just waiting for my flywheel and associated single use bolts to arrive now.
I'm not a one for fixing anything that ain't broke "while I'm in there". The bike has only done 45,000 miles, the clutch plate measures 5.16mm thickness, (new 6mm, BMW recommended limit 3.5mm)
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I, for one, would be glad to know how this crown has sheared it's rivets. What kind of steel they used at Sachs ? Bubble gum ?
It is very strange but not unheard of but it is the first time I see pictures of it.
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Some of the holes in the ring gear look slightly oval now. I suspect that the ring has been rattling backwards and forwards a few thou for quite a while and this has finally resulted in failure by metal fatigue.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.photo-electric.com%2Fimages%2Fbmw_ring.jpg&hash=d8d401ee9a28dd4764090c3b325a63bd43281d40)
For the last 100 miles or so I could hear a noise which sounded to me like the timing chain. So I changed it. In hindsight this was a waste of effort and money as the old components were fine. The noise was probably the ring gear rattling.
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Has anyone else come across this?
The starter ring fell off my flywheel (well clutch carrier to buy into BMW "Newspeak" a couple of years back - symptoms were near identical to what you describe.
It turns out that this is a sufficiently frequent occurance that sellers of 2nd had partsa think that their offerings are made of solid gold.
It is also the case that BMW had a couple of goes at using different size/composition rivets and that only the most recent ones appear to be immune.
On the basis of the prices demanded by wreckers and not wanting to have to deal with the matter again, I bought a new one.
Don't forget to mark your clutch pack so that it goes back with the same relative positions.
Also not a bad idea to replace oil pump deal and rear main seal whilst you are there, along with the gearbox input shaft seal.
Getting the gearbox off and the flywheel out is not a job you want to do too often.
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Thanks Tony - I did see your post about it.
I ordered a new flywheel, but they were not in stock and Motorworks were unsure about delivery due the the current virus conditions here in plague central. So I changed the order to a second hand one. £75 as opposed to £165 + VAT.
I found the original paint marks on the clutch parts and the replacement flywheel and put them in 120 degrees apart.
It's fitted back on now, together with the clutch. I decided against replacing seals, just to minimise time and effort. I hope this doesn't come back to bite me. My experience of "I'll just do this while I'm in there" always seems to lead to unexpected problems.
I should get the gearbox back in over the next few days.
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Replacement fly wheel fitted. My torque wrench only goes up to 50ft lb and I needed 80. So a two foot lever and a luggage scale was used to measure 42 lbs. (The extra 2lb was the weight of the lever)
Clutch fitted using a home made clutch centering tool, which must have worked OK as the gearbox is fitted now.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.photo-electric.com%2Fimages%2Fbmw-cluch.jpg&hash=e327b3e9251cde053a441ce6494af7d96d5df4f5)
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.photo-electric.com%2Fimages%2Fbmw-clutch-tool.jpg&hash=19eb8fb4a0c0e3c313dd8067f58eb997a4b2d025)
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All back together now.
It took a little longer than expected as I dropped a drive coupling bolt into the drive shaft housing. So I had to take the entire back wheel and swinging arm of to tip it out (along with the drive shaft oil over the garage floor).
I took it out for a 20 mile test run, and it feels fine, and no rattles!