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Old 08-06-2012, 03:56 PM   #1
band-aid OP
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Question BMW R60/6 - Clutch and other advice

Hi,

A few questions for all you knowledgeable airheads out there.

The first is clutch related-

So, I just took a 1300 mile trip two up with luggage on my 1974 BMW R60/6 and learned a little bit about my bike along the way.

Section 1:

Anyway, at some point during a week long trip the clutch started acting up in the following manner. I would start the bike in the morning and find that the clutch would chirp when engaged and while being slowly released in first gear. First gear would engage and as I released the clutch the bike would start moving as normal. Before reaching the maximum RPM for first gear I would be able to rev the bike and the power would not transfer into motion and a loud chirp would be heard. The same thing would happen in second gear and possibly third. I could hear the engine revving but the clutch would just (I suspect) slip. After about 10 minutes of riding, the clutch would engage and disengage normally without acting up and I was able to ride all day without seeing those symptoms again.

At a certain point towards the end of the trip while on the highway I attempted to downshift from 5th to 4th (perhaps while going slightly too fast for that change and under load) and the chirp returned full force and the bike lost all power to the wheel- After frantically shifting up and down for a long 10 seconds I regained power in 4th gear and shifted back to 5th and kept riding.

After finally getting home a week later I notice that now when I squeeze the clutch (even in neutral I believe) a very tiny squeal (less pronounced than the loud chirp) is heard. Believe it or not the bike still runs and shifts well throughout all of this.

Also of note- there is lots of dust in the timing window which my mechanic mentioned to me meant I likely needed a new clutch soon. Also notable is that the bike has a newly rebuilt transmission by a very reputable NYC BMW guru so I think the gearbox is good- and it shifts very well.

So my questions are- A: What's wrong exactly? Plates or throwout bearing? Both? I'm prepared to replace the clutch which I believe is likely but what specifically has failed/is failing? B: Anyone have a good site for purchasing clutch parts? C: How difficult is a clutch job? I've just recently done a timing chain and alternator on a friend's R80 with success so I feel fairly handy but I have no clutch experience. I own a clymers...


Section 2:

My R60/6 is very pingy at certain RPMs (especially under load)- Probably about 2500 rpms- I'm not sure exactly because I have an acewell speedo that doesn't indicate true RPM since it's an induction wire at the coil.

Also the bike has an electronic ignition (DYNA) that was installed prior to my ownership- I have read that this unit may advance the timing too much and thus cause pinging (and it's not adjustable?)

Compression tests show that the bike has about 170 PSI at each head which is a little high- Carbon build up?

I have not actually checked the timing because I didn't own a light- though I do now and intend to check it this weekend- though I don't think I can actually adjust it.

So, what are the likely causes and what are the easiest fixes? Does the Boyer Brandsen unit offer adjustability if I were to change out the electronic ignition? Would I be better off with points?

Section 3:

Lastly, my bike consumed quite a bit of oil on this trip - Approximately 1 liter/ 800 miles- Smoke blows out the right pipe more than the left intermittently- I think mostly at higher RPMS in each gear. I think this one is more obvious but what is the cause in your opinion?


Bike has 70,000 miles on it roughly.

Thanks in advance for all of your responses- I intend to work on the bike regardless of the problems as I really, really like it.
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Old 08-06-2012, 04:39 PM   #2
photorider
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Here is my $.02...

-Sounds like it's time for a new clutch. I think conventional wisdom is to replace all the parts together but you might get different opinions. DIY? Sure!

-It also sounds like the top-end needs attention. Carbon build-up could be causing the pinging and high compression but keep in mind these bikes have a tendency to ping even when everything is squeaky clean. Oil consumption and smoke could indicate you need new rings. Not a difficult job.

-The Dyna is a good unit and yes, you can adjust the timing. Just rotate the sensor plate.

-My experience with pinging is that you need to change the advance curve to make it go away. The Dyna uses the stock advance unit so you have to make modifications to it. First, I would make sure you have the thicker springs. If that doesn't do it, there are these little brass collars you can get (don't ask me where) that fit around the the posts that hold the advance springs. They supposedly retard the advance curve 5 degrees. I got a set with a used advance unit I purchased and they worked like a charm. No more pinging!

Good luck and keep us posted!

PS A lot of people snub their nose at our little R60/6's but, like you, I have a soft spot for mine. It was my first "real" bike and I plan to hold on to it for a long time. It took me a while to get it all sorted but now it puts a smile on my face every time I get on it.
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Old 08-06-2012, 05:21 PM   #3
disston
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The amount of use you seem to be getting out of this old girl I think she deserves the entire clutch job. Yes this is the way it is recommended by those in the know. There are two pressure plates, the clutch disk and the spring. You should also pay attention to the condition of the bolts that hold everything together. Some of them do not have to be changed and some do. If any of them look or thread in ruff, even if there is not a recommendation to change them do so anyway, if they are damaged, etc, etc.

There is a cheaper alternative. You send the clutch parts you now have to Southland Clutch and they will machine the surfaces so you don't have to buy all new parts. The Southland Clutch works as a regular BMW clutch but the parts they give you back can not be mixed with regular clutch parts. This is also kinda new but not that new. I've not seen any reports yet that the Southland Clutch doesn't last as long or anything else. So far all reports are from happy customers.

If you take this to a shop they are finished in one or two days. If a Do It Yourselfer does this at home it is usually anywhere from several days to all Winter. Mine took all Winter this past year and I pretty much know what I'm doing, I'm just slow sometimes. And I found several problems. Since I had the trans out and was doing the clutch I also did the rear engine seal and the oil pump O-ring. That is something extra to consider. Because the majority of doing that job is already taken care of, getting the trans out.

Here's the Southland Site;

http://www.southlandclutch.com/

That saves about 50% over dealer prices I think. There are cheaper places to buy parts but I imagine they will save only 10 or 15 %
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Old 08-06-2012, 06:09 PM   #4
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It sounds to me like the throw-out bearing is hanging up in the bore. It slides in a bore in the transmission rear cover and sometimes gets deformed. Not sure why, maybe wasn't getting the lube it should have. Whatever, once it gets rough and hogged out in there, it's possible for the throwout bearing to hang up in there.

That would be my guess. And it's easy enough to check out, but may require tilting the engine to miss the frame cross bar when attempting removal of the rod and bearing.

Who knows about the clutch? It may last a thousand more miles or 40 thousand. No way to tell at this point, but clutches don't not work for a while and then sort themselves out all by their lonesome. I don't suspect the clutch at all!

170 lbs compression is pretty good, but combined with the oil consumption, it's quite possible the rings are glued to the pistons. Maybe a de-coking will fix both issues, consumption and pinging.
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Old 08-06-2012, 06:23 PM   #5
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What Wirespokes says makes a lot of sense.
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Old 08-06-2012, 10:20 PM   #6
Wirespokes
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I wouldn't have thought of the throw-out bore being sloppy if I hadn't seen it in a transmission cover that needed fixing. The machine shop bored it out and shimmed with brass. It's much stronger the second time around!
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Old 08-07-2012, 08:16 AM   #7
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Good clues

Thanks for all the advice. I was thinking that there might be an issue with that throwout bearing but does that account for the loss of power? It definitely would account for the squeal according to what I've read elsewhere. What about all the dust in the timing window? Is that from wear on the friction plate?

As far as the pinging goes- is the consensus to decarbonize the heads and see the results first? Wirespokes- I think you may be right about the rings- maybe it just needs cleaning - maybe they would have to be replaced.

Photorider, thanks for clarifying about the DYNA... I can adjust the timing just by rotating the plate (if it's off) but what I really may need to adjust is the actual advance curve of the unit which would require thicker springs or brass collars? Does anybody know of a thread or other resource that might give me some clues on how to modify the DYNA?

Really appreciate all your thoughts on this so far and I will keep you updated as I deconstruct!
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Old 09-25-2012, 08:03 AM   #8
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Question Clutch gone

So after another ride, the clutch failed completely on the way home. I could hear some light scraping and then suddenly no clutch.

The bike has already been torn down and is sitting in my shop without a transmission or clutch in place. So upon inspecting all of the clutch parts I found essentially that everything was worn but I didn't notice any catastrophic damage of any kind. My stupid question is, what separates a worn clutch from one that doesn't work at all? I am about to replace all of the components but I just want to be sure I'm not missing something.

By the way, I would say the friction plate is worn to about 1/2 the thickness of the new unused replacement I have.

Also I haven't investigated the throwout bearing yet but will do now that I have the tranny out.

Last thing, what paste should I use where appropriate or assembly? I was planning on hondamoly60 for the splines and the tips of the spring. Anything else? Snobum says to use a light non moly grease for a few other parts including the throwout bearing...
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Old 09-25-2012, 08:09 AM   #9
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Quote:
Originally Posted by band-aid View Post
So after another ride, the clutch failed completely on the way home. I could hear some light scraping and then suddenly no clutch.

The bike has already been torn down and is sitting in my shop without a transmission or clutch in place. So upon inspecting all of the clutch parts I found essentially that everything was worn but I didn't notice any catastrophic damage of any kind. My stupid question is, what separates a worn clutch from one that doesn't work at all? I am about to replace all of the components but I just want to be sure I'm not missing something.

By the way, I would say the friction plate is worn to about 1/2 the thickness of the new unused replacement I have.

Also I haven't investigated the throwout bearing yet but will do now that I have the tranny out.

Last thing, what paste should I use where appropriate or assembly? I was planning on hondamoly60 for the splines and the tips of the spring. Anything else? Snobum says to use a light non moly grease for a few other parts including the throwout bearing...
Whatever you do, put in a brand new spring. trust me. Sometimes they give up the ghost when removed and you don't find out until after the reassembly. I learned this the hard way.
It doesn't always happen, but since it's the cheapest of the 4 parts, it's a good idea.
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Old 09-25-2012, 08:50 AM   #10
Bill Harris
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Exactly what Wire^1 says, probably the throwout bearing as well as worn clutch components. Replace the cable unless it's silky-smooth and looks cherry.

Also what Wire^2 says. The diaphragm spring may be good today, but may give up the ghost in 5-, 10- or 15,000 miles. Replace with new.

Fix the clutch now since it is a known issue and be prepared to tackle other issues as they crop up.
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Old 09-25-2012, 09:30 AM   #11
disston
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Check the throw out piece's now. That three of us that have told you this.

You take the throw out arm of the rear of the trans, all the parts can be extracted with a needle nose pliers and sometimes a magnet. Refer to the parts diagram on http://realoem.com/bmw/ to see, make sure, you got them all out.

The long rod comes out the front easier.
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Old 09-25-2012, 01:50 PM   #12
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Eek Throwout

Thanks all. I am replacing all four of the clutch components and I already have a new throwout bearing (needle cage?) ready to go if necessary. I will pull that apart on Thursday and start the reassembly. Does anyone have any thoughts about the grease though? Besides HondaMoly60 for the splines and tips of the spring what grease should I use for the throwout bearing for example?
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Old 09-25-2012, 02:30 PM   #13
disston
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The Honda Moly 60 grease is the current recommendation for the input splines. It doesn't seem to do much better than some of the other things we have used through the years but it does have the Molybdenum that we like. In theory what this is is a high pressure grease that works with the pressures seen by those splines. There are those that would have you believe it does no good. I say it does no harm and it may in fact be of benefit. So use it.

The application is extremely important. Put the grease only on the input shaft itself and not on the splines of the clutch disk. When the two parts mate, that is when the trans is bolted to the rear of the engine, any excess grease will be pushed rearward if this excess is on the input shaft. Because of clearance and design features a little excess grease here will do no harm. However...if you put grease on the internal splines of the clutch disk it will be pushed forward where from it will be thrown by centrifugal force outward and onto the clutch disk.

You are also advised to use a very tiny amount of grease. Just enough to coat the splines but not to fill the valleys in the splines.

I don't know if Honda Moly 60 is suitable for the other parts. I think not. I use my ordinary wheel bearing grease for anything else. Like the thrust pieces and the pressure plate fingers. Wheel bearing grease is not expensive. They sell a really high quality one at motorcycle shops all over. The expensive one is still only $10 for the tub. This much grease should last most riders 20 years or more. Be careful to not get dirt or debris in the tub. I have a smaller canister I keep with the tools on my bike.

The grease on the throw out bearing and parts is for start up and run in only. The trans drips a small amount of trans fluid on these parts to lube them in operation. If the trans was run low on fluid or the orifice got plugged somehow it could be the reason for destruction of the bearing and/or thrust pieces. If the bearing goes bad, i.e. the bearing you have not removed yet (?), the rear cover may need to be replaced or machined to put it back in spec. A bad throw out bearing will take other things with it when it goes.

The long rod is best removed and replaced through the front of the trans. If the felt seal on the rod looks in good shape, they usually are, then forgo a new one and use the old one. New ones are improperly sized and difficult to put on.
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Old 09-25-2012, 02:32 PM   #14
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I recommend you replace that bearing no mater how good the old one looks. The design is not a good one. Your only defense is a new bearing. Throw the old one away.
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Old 09-25-2012, 04:47 PM   #15
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Charlie - I'm ashamed to report I just removed and cleaned and greased my chirping throwout bearing (crappy flat needle bearing style) the other day. I forget when I first installed it...might've been as much as 50K miles ago. It came out pretty dry but my thrust washer and piston didn't seem worn so I cleaned the cheap throwout bearing up, made sure all the little needles were rotateable, and greased it with my blue waterproof grease and reinstalled, using a little Honda Moly on the thrust bearing surface. Result? Chirp gone, shifting smoother (this is the same effect you get when you wash your car and it runs better). I'll be giving it a good run to NH in October and expect it to explode somewhere near Lake Winnie.
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