1200 exhaust valve burnout

[cookie]

At start-up the only lubrication is oil that is already in the bearings and journals - the pump will build pressure and it will then be fed to everywhere from where it has drained - only a momentary starving of oil but it can add up over many many cold start cycles. My 49,000 miler has a small chatter at start-up which disappears after a second or 2 when the oil gets back to where it should be - not unusual - but I'm sure it's more from the RH side if it's been on the side stand for any length of time. I know from talking to plenty of other boxer owners that there's plenty that prefer that if the bike is left, particularly overnight, it goes on the centre stand not the side stand. This is unlikely to be the cause but can certainly be a contributing factor.

owners of jap 4s must get the top end exploding business all the time then. and all them car engines too.


no wait, they don't

 

[cookie]

Clearly isn't understood..

Apparently leaving it on your side stand also damages the left sidewall of your tyres.

sorry

 

[Jugsy77]

Happened to me and just happened again today

The first time the engine wouldnt idle at lights, it would just cut out and the red hazard light kept coming in ..2 dealers couldnt find the cause the 3rd find out that the piston under the tank that realises oil into the engine to call it down had stuck so this caused the engine to overheat the blow the valve

Its happened again today commuting to london, loss of compression

I have extended warranty that fixed it the last time, but after big arguments with bmw becuase they were saying it was wear and tear..bollx

Now due for 36k service and have to do it again..not impressed with the world touring bike

 

[Bobbin-Man]

Cookie, not suggesting it's the cause of the problem - simply that the additional time the oil takes at every cold start-up to get to the right hand head may contribute to the fact that failure is always the right head valves. Jap 4 comparison irreverent - the oil drains from all the cylinders the same. When there's a consistent failure on one side only of an engine type then differences need to be investigated - same valves used both sides etc.

I'm in the process of rebuilding a highly tuned car engine - major failure on nos.1&2 big end bearings. Common failure on same type of engine running this spec - always the same bearings. Always caused by reduced oil feed to the front of the engine because that's the way the feed was designed. Everything okay, no failure, but if something's compromised the same failure manifests itself repeatedly.

 

[Pauly S]

now heres a revalation..

The 1200 has two oil pumps, one for cooling and one for lubrication..
hands up who knew that then?
Re previous posts, it would appear the upper exhaust valve went tits up.
I'm looking into possible errors in the fuel/ign map, a possible dodgy lambda probe causing one cylinder to run lean,lubrication failure, although the head of the valve dropped off, well into the combustion chamber, so i doubt the best oil on the planet,would have saved this valve head.
Its hard to analyse the piston as the owner had to drill the piston off.
Still its getting lots of love during the total re-build, with lots of lovely new BMW parts,and its will be like new when i'm finished.
I'll post some pics of the head, its the best yet, it knocks Jaythros into a cocked hat.
The bike is getting a new crank, rods, barrel,piston and head, and lots of love.ahhh.xx

 

[Pauly S]

welcome aboard matey

On Christmas day I dropped the exhaust valve on the right cylinder on my 2007 GSA with 33k miles on it. I was going about 80 mph at the time shifting from 4th to 5th gear as I merged onto the freeway, trying to go fast to see if I felt any wheel shake after installing ceramic balancing beads inside a new set of Karoos. Suddenly there was pop and a loss of power as I was streaming smoke and spewing oil like a downed P-52 Mustang.

This happened the day before we were supposed to leave for a 6 day Baja Mexico trip on the big bikes. I ended up having to take my small 450 dual-sport instead...what a bum deal.

Anyhow, I've got the bike on the lift and after pulling the exhaust and spark plugs the damage looks identical to the photos posted previously...I haven't yanked the head yet to see if I punched a hole in the piston, but stay tuned.

it will have to come to bits....be prepared...have lots of small freezer bags for all the hundreds of bolts you'll find coming out of it.
ive done well so far,there was a great fear i would need several specialist tools, but i've made most of them so far.
Any how welcome to the loony bin.

 

[cookie]

i'll put my hand up re: oil pump

i don't think oil has anything to do with it. i'd say it's likely a heat issue, but why it only affects the RHS is a mystery to me (and bmw by the look of it).

 

[Schtum]

a possible dodgy lambda probe causing one cylinder to run lean,

I think this one's unlikely. The lambda sensor only impacts on the fuelling in closed-loop mode when the engine's not working hard enough or generating enough heat to create the kind of failure that it's experienced.

Out of interest - was the bike fitted with an aftermarket exhaust system?

 

[Deleted account 190920001]

Cookie, not suggesting it's the cause of the problem - simply that the additional time the oil takes at every cold start-up to get to the right hand head may contribute to the fact that failure is always the right head valves. Jap 4 comparison irreverent - the oil drains from all the cylinders the same. When there's a consistent failure on one side only of an engine type then differences need to be investigated - same valves used both sides etc.

I'm in the process of rebuilding a highly tuned car engine - major failure on nos.1&2 big end bearings. Common failure on same type of engine running this spec - always the same bearings. Always caused by reduced oil feed to the front of the engine because that's the way the feed was designed. Everything okay, no failure, but if something's compromised the same failure manifests itself repeatedly.

Your an engine builder and you still maintain its oil drain that could be the problem? Of course an inline 4 is relevant, all the valves would break if it was oil drain. As I said before if it was an oil issue the cam would be the first to suffer and they aren't.
I have given you evidence as to why it isn't a lubrication problem so can you as an engine builder give us evidence that it is?

 

[cookie]

did it have water in the fuel? that's one theory i've heard.

 

[DrFarkoff]

Look Gang I am no metallurgist but I've been Mechanical electrical engineer for nearly 30 years now

So we have a 5 mm valve shank that is sodium filled with a friction welded head.....

Running a 15 to 1 air fuel ratio.......

Anyone ever hear of one of these with an accelerator module drop a valve????

With an air fuel ratio of 15:1 they run hot DAMN HOT couple that with "possible" tight valve clearances and the valve not getting to seat for it's full duration to dissipate said heat .......

Well somethings gotta give

You think I'm joking go find someone with a K1200RS and get them to ride up the road at 70 or so for 5 mins and then get them to pull over and see how hot the tail can is!
DO NOT PUT YOUR HAND ON IT! They were one of the leanest running engines in the bmw fleet till some green twat whinged about cat converters

 

[Jugsy77]

Dealer said to me

The oil piston under the the tank had stuck shut, which means it didnt allow oil into the engine to cool,it down

They took it out and put it into a bucket of hot water and it should have opened but didnt, replaced it under warranty and worked greats for a year, but now its happened again, engine over heating, loss of compression, doesnt stay a 1000 rpm when idle, just cuts out

 

[cookie]

The oil piston under the the tank had stuck shut, which means it didnt allow oil into the engine to cool,it down

They took it out and put it into a bucket of hot water and it should have opened but didnt, replaced it under warranty and worked greats for a year, but now its happened again, engine over heating, loss of compression, doesnt stay a 1000 rpm when idle, just cuts out

is that the thermostat he's talking about?

 

[Pauly S]

exhaust..

I think this one's unlikely. The lambda sensor only impacts on the fuelling in closed-loop mode when the engine's not working hard enough or generating enough heat to create the kind of failure that it's experienced.

Out of interest - was the bike fitted with an aftermarket exhaust system?

no its standard, i had a duff lambda probe near kill me on the 1150 , for some dumb reason the probe shut the engine off, midflight in an overtaking manouver.
I unplugged the probe and it got me home with no further problems.
i just cant think what would make one cylinder run hot enough to trash the valve.
Its either a shit valve,its too hot(why is the other side ok?)Air leak, dont think so, it was doing 80 mph at the time it fecked orf.
prior to the death, there no lack of power either, thats why i'm thinkng it was running slightly weak and too hot

 

[Schtum]

is that the thermostat he's talking about?

I do believe it is.....

 

[Schtum]

i just cant think what would make one cylinder run hot enough to trash the valve.

As you've already indicated, I think it'd be a wise move to find out which version of the software is in the ECU.

I also think it'd be a mistake to try to tie it down to once cause for every case of a bike dropping a valve, even if it is always on the right-hand pot. I think it's more likely that there are a number different possible factors in each case.

 

[Pauly S]

I think

The oil piston under the the tank had stuck shut, which means it didnt allow oil into the engine to cool,it down

They took it out and put it into a bucket of hot water and it should have opened but didnt, replaced it under warranty and worked greats for a year, but now its happened again, engine over heating, loss of compression, doesnt stay a 1000 rpm when idle, just cuts out

i think you are on about the oil thermostat which controls the flow to the oil cooler, adjacent to the alternator on the right side.

 

[Pauly S]

good points

As you've already indicated, I think it'd be a wise move to find out which version of the software is in the ECU.

I also think it'd be a mistake to try to tie it down to once cause for every case of a bike dropping a valve, even if it is always on the right-hand pot. I think it's more likely that there are a number different possible factors in each case.

If the bikes were all the same, then you could try and work it out.
different exhausts, different software,and it goes on.
I'm, gonna re-build the puppy, clean all the oilways totally,and go from there.
As previously said, i wonder if an overtight tappet may have done it.

 

[Bobbin-Man]

Your an engine builder and you still maintain its oil drain that could be the problem? Of course an inline 4 is relevant, all the valves would break if it was oil drain. As I said before if it was an oil issue the cam would be the first to suffer and they aren't.
I have given you evidence as to why it isn't a lubrication problem so can you as an engine builder give us evidence that it is?

You really didn't read my post did you 1st line .... "Cookie, not suggesting it's the cause of the problem" !!!

 

[Jugsy77]

i think you are on about the oil thermostat which controls the flow to the oil cooler, adjacent to the alternator on the right side.

Think you are right about the thermo, the dealer told me it was this that caused the right handside to go bang