cracked piston....

[hoflix]

Was going to work last Wednesday, everything felt normal, until I got off the freeway and at the exit I noticed the bike was barely idling, shaking like a harley and sounding like a lawn mower. It did not stall though.
Called my dealer (Long Beach BMW) and based on my description, they assumed it's a blown coil. No problem. Apparently, they had it in stock, just get there and they'll fix it.
After work, the bike didn't start thou... or it did, but needed constant throttling. So BMW roadside assistance, tow-truck, traffic, barely made it to the dealer before closing time. Can't be fixed on the spot though. Bike is under warranty, no problems there.

This is really bad timing, I had a 4 day trip planned, starting Thursday.

I was given an F800ST loaner bike, and even a topcase for it, when I started crying about my thanksgiving trip (none of my r12r cases would fit on the 800)
So I left on my trip on the loaner bike (and i must say it's really really nice... maybe I'll write a "trip report on a loaner bike" ).

Dealer called Friday, they found the problem: the right piston is cracked and held together only by the piston rings apparently. Research shows it's not uncommon...

Got a call again today (Wednesday), the piston came from Deutschland, the bike is being worked on, and I can pick it up tomorrow.


Now I'm trying to figure out if there's anything else that should be checked/changed while doing this repair:
Oil? I assume it will be changed, since the old one would be contaminated with gas. (right??)
Valves?
TB sync?

This might seem a little extreme maybe, but I read about the necessity of taking the other piston out too and weigh it to make sure they are within 10 grams of each other.
Should I bring that up?
I have the CD manual somewhere, gotta look it up.

[Mollygrubber]

Yikes!

Sorry to hear about that, especially the 'not uncommon' part.

I have to admit, I have not heard that before. Makes my occasional 200km/h blast during the morning commute seem a bit risky (or, a bit MORE risky, to all you old folks )

Is this indeed something to fear?

Peter

[xprof]

Peter,

Your stones must be impressive! What I remember of Vancouver AM commuter traffic, 200km/hr does seem a bit fast...

[hoflix]

there's a few cases of right cylinder/piston failures on r1200 engines.
not a lot though... like 1:10000 maybe

[Mollygrubber]

Peter,

Your stones must be impressive! What I remember of Vancouver AM commuter traffic, 200km/hr does seem a bit fast...

Gosh, thanks! My wife thinks so...

I am heading south towards the Peace Arch border crossing on my way to work - no (well, very little) traffic at 5:30am...

Wait a minute - you're not a highway patrol officer are you?

[deilenberger]

This is the 2nd time (I think - the first one was SO long ago..) that I've heard of this sort of piston failure in a Hexhead motor. I don't believe it's at all "common".

Certainly the dealer should do an oil change, valve adjustment and TB sync considering the entire cylinder was disassembled. They also should call you back in at 600 miles to re-torque the head and re-do the valve adjustment again (just like with a brand new engine..)

I would be a bit concerned about any cylinder damage the cracked piston may have caused, and if it was me - I'd like to see the cylinder before reassembly takes place (but I know what I'm looking for - primarily any gouges or scratches in the cylinder lining..) The piston balance is also somewhat of a concern.. dunno if you can convince them to disassemble the other side, but if I was doing it myself - I probably would (and then grind away a bit of the underside skirt or ribbing on the heavier piston to try to get them exactly balanced..) If you can find it on the CD - then print it out.. well.. the dealer would have a hard time NOT doing it.

Damn. How many miles on the bike?

[hoflix]

Thanks for the reply.
I just realized, saying "not uncommon" makes it "common". It's not. That came out wrong. There's been a few cases, that's it. I'm not concerned.

Bike had 11.805 miles... getting close to the 12k service. So I guess part of it should be done. What's left? Flush the rear drive and brakes?

I did find the mention about the piston weight in the manual:


Very interesting notes there (in case the picture doesn't show)

===================begin quote ======================
Attention
There is only one tolerance group (A/B) for replacement pistons and cylinders. There are two other tolerance groups (A and B) for components installed ex-works. Piston and cylinder must belong to the same tolerance group.

Always replace piston and cylinder as a paired set.
The pistons for the right and left sides differ; do not mix up the pistons.
-----------------------------------------
Determine the correct tolerance group (2) of the piston and use a piston of the appropriate tolerance group.
-----------------------------------------
Attention
In order to ensure low-vibration, smooth engine operation, all the pistons must belong to the same weight class.
Always use pistons of the same weight class in any one engine.
-----------------------------------------
Determine the correct weight class (1) of the piston and use a piston of the appropriate weight class.
-----------------------------------------
Note
The weight class is stamped on the piston crown and is legible only if the piston is new.
If the symptoms are such that only one replacement cylinder with piston has to be installed, the weight of the other piston has to be ascertained by weighing.
------------------------------------------
Technical data
Difference in piston weights within a weight class (weight classes 0 and +)
Complete with piston pin and piston rings max 10 g

==================== end quote ===========

[deilenberger]

Did that make any sense to you?

To me it sound as if they are saying:

----------------------------------------------------------------------------------

There is only one tolerance group - Group A/B
There are two more tolerance groups - A or B tolerance groups

Replacement pistons are all class A/B (is that either-or? Or what?)
Pistons installed x-works (does that mean out of the factory, or in the factory) are all A *OR* B tolerance group.

The pistons are marked as to the tolerance class - but once used the markings go away (probably inked on.)
Always replace the piston and cylinder as a set - with the same "tolerance" groups.

---------- I suspect tolerance class means the piston/cylinder fit --------------
----------------------------- maybe -------------------------------

Then it goes into weight classes - which they don't explain but they tell you to use the same weight classes, even after the markings disappear from the pistons.

And if you're only replacing 1 piston - it has to be weighed against the piston not being replaced and shouldn't vary more than 10g,

----------------------------------------------------------------------------------

I think the part on weight classes is the important part, and can't see how that
can be determined without taking the other cylinder apart and weighing the piston.

[hoflix]

I was confused too ...ex-works???
I had to google it "ex-works=Term of sale signifying that the price invoiced or quoted by a seller includes charges only up to the seller's factory or premises. All charges from there on are to be borne by the buyer."

I think it means factory installed.

So the way I read that is:
-----------------------------
There is only one tolerance group AB for REPLACEMENT pistons and cylinders. (parts ordered later?)
There are two tolerance groups (A and B) for components originally installed at the factory. [....]
-------------------------------

So it would appear you can only order 1 kind of piston+cylinder set (?) and they should be replaced as a set.
But this only raises more questions.....

[deilenberger]

I was confused too ...ex-works???
I had to google it "ex-works=Term of sale signifying that the price invoiced or quoted by a seller includes charges only up to the seller's factory or premises. All charges from there on are to be borne by the buyer."

I think it means factory installed.

So the way I read that is:
-----------------------------
There is only one tolerance group AB for REPLACEMENT pistons and cylinders. (parts ordered later?)
There are two tolerance groups (A and B) for components originally installed at the factory. [....]
-------------------------------

So it would appear you can only order 1 kind of piston+cylinder set (?) and they should be replaced as a set.
But this only raises more questions.....

I think you're right - and I wouldn't be concerned too much about the "tolerance group" since I suspect that is the piston to bore "fit" - and small differences side to side won't make a lot of difference. What I would be concerned about is the weight.

[hoflix]

I got the bike back today realized how I missed her

They replaced the piston and the cylinder (part #11257703060 and 11117673530). No, they didn't weigh the other one.
I asked the tech, he said there's only one replacement piston he can order anyways. Apparently, on the r1150 motors there's 4 possible pistons (A, B, +/-) and weighing it's a must, but on the r1200 you can only order the AB "tolerance group".

Weird, considering the manual says it must be weighed... why do that, if there's only one available? or maybe they can machine one or the other to match?

I looked around a little and on the maxbmw site you can only order 1 piston for the r1200r http://www.maxbmwmotorcycles.com/fiche/ ... 005-072009
AB 587grams
However, for an R1150R it appears there's 4 variations indeed: http://www.maxbmwmotorcycles.com/fiche/ ... 00-022006#
(AB+584-594GR), (AB- 574-584GR) whatever that means

Problem is... the bike does seem to vibrate more now. I pointed that out, they checked the TB sync but it was OK. The service manager had a pretty good explanation: the new piston has perfect (and higher) compression now, so the engine will feel out of balance for a few hundred miles, till it's broken in. I'm not sure what will happen if it still does it after that...

I am supposed to go back after 600 miles, to have it re-torqued... and possibly do the 12k miles service.

They did not change the oil. I should have pushed for it, I know. At least 2 reasons to change it: gas contamination (was running in one cylinder after all) and loose particles from the cracked piston. I was told no parts were lost from the piston, it's all there, was held in place by the rings. That can't really be true... if you "zoom in", on a microscopic level there will be metal particles.

I had a chance to examine the broken piston, and I took a couple of low quality pics with my phone:

[hjsbmw]

Holy cow! It's good that they replaced the cylinder also. Not doing an oil change seems frugal for the wrong reason. I'd rather do it myself than go back and argue with the dealer.
Shouldn't a new piston and cylinder have imperfect compression rather than perfect compression until they are run in? The effect would be the same though, I suppose.

[deilenberger]

+1 on Herr Haralds suggestion. I wouldn't panic 'cause the oil filter should catch even microscopic metal bits - but I'd want to change the oil. Cheap insurance. Be interesting to send a sample to Blackstone to see if the old oil is contaminated - but cost of curiosity may be too high (I think it's $25 without the extended use test.)

Oh - the "(AB+584-594GR), (AB- 574-584GR) - AB+ is the heavy range piston (584-594 grams), AB- is the lightweight ones (574-584 grams.)

[hoflix]

I'm thinking about waiting for 600 miles to do the oil change.
I mean, I'll change it anyways when they re-torque the head is a week or so. I's got synthetic in it right now.

As far as vibrations... I gotta do more research, if it can be indeed a different piston weight issue.

Anyone in Los Angeles wanting to test ride my bike? for comparison... maybe it's all in my mind

Anyone riding around Malibu or ACH this weekend?

[celticus]

I'd keep a very close eye on the bike. It sounds like your dealer is not going the thorough route. Also sounds like the service manager does not know at least in this case what he is talking about.
Wait for 600 miles to change the oil? Is this a brand new bike? Is there a chance to trade this one for another R1200R? One hopefully with less chance of cylinder damage?
I am not trying to be a downer (as the young people say or used to say anyway ) just cautious.
Good luck. Keep us informed.

Mark

[hoflix]

well.... I've done approx 250miles since I got the bike back, and I can swear the vibration is not as bad as before.... so it's all good. (or maybe I got used to it?!?.. LOL)

I'm actually happy with the way the dealer solved my problem... the only thing is I would have hoped for an oil change.

But there's a big change in my mind tough, in the way I look at BMW: I used to think BMW is really "unstoppable", best of the best, and I could just get on it and ride it around the world.
Well... it's not.


PS: Don, I do understand all devices work till they don't, and then they are broken

[celticus]

" I used to think BMW is really "unstoppable", best of the best, and I could just get on it and ride it around the world. "
Hopefully this will just be a bad (OK REAL bad) memory soon.
Is that you dragging your knee in your Icon? Impressive, most impressive. As my Dad used to say.

Mark

[Mollygrubber]

I used to think BMW is really "unstoppable", best of the best, and I could just get on it and ride it around the world.
Well... it's not.

I love them too, but at the end of the day, they're just machines, and only as good as the guy bolting them together. They suffer from bad batches of raw materials, a Monday morning after Oktoberfest hangover in the QC department, and the guy in the middle of a messy divorce selecting piston pairs.

The Long Way Round/Down bikes certainly didn't make it around the world without problems, and their bikes were "prepped" for the trip. Albeit by Ewan & Charley...

Your issue seems pretty rare, and was fixed in a timely fashion. I'm sure BMW knows 'we' talk about their products, they want them to be as good as their advertising. But they are humans too, despite me thinking the whole factory is run by friendly terminator-type machines.

[hoflix]

Your issue seems pretty rare, and was fixed in a timely fashion. I'm sure BMW knows 'we' talk about their products, they want them to be as good as their advertising. But they are humans too, despite me thinking the whole factory is run by friendly terminator-type machines.

Yup, I agree.
Hey, do you think BMW is really "listening" to this? if so, dear BMW, could I get a motorrad t-shirt ? size M

Is that you dragging your knee in your Icon? Impressive, most impressive. As my Dad used to say.

Well... due to the boxer config of our bikes, we don't have much lean angle, so hanging off is mandatory

[Gatuso]

Sorry about your trouble Hoflix, but it seems is fix now, say I notice you are in Los Angeles and so am I, and yes I love going to the local canyons, ACH,GMR,Santa Monica Mountains (Rock Store), Azusa......the thing is that I'm off on Mondays and Tuesdays so if you want to go to the canyons and a cup of coffee let me know.

If you want I can do an oil change for you, I try to stay away from dealers as much as possible, I'm in Downey.

Lates.

Rudy