Major Piston Problem......help!

StooL · Apr 4, 2004

My 1150GS stopped running on one cylinder on my journey home from work last night. I have stripped the bike down today with the help of my father who is a mechanic and we have found that the right hand piston has a nasty great hole in it. This has also scored the cylinder and I'm now facing the cost of buying some very expensive parts. For a bit of peace of mind, we also stripped the other side and found that it is ok.

The bike is a year 2000 model with only 20,500 miles on the clock. I use my bike for commuting into Edinburgh most days, which is a run of 30 odd miles up a country road with about 10 minutes of heavy traffic work at the end. I don't hash the hell out of it and I doubt the engine is getting too hot, especially at this time of year. I fitted a Y-piece and Remus can 2000 miles ago. I have read most of the threads on this and refitted the Lambda sensor but could not retain the cat code plug as my bike did not have one?! The bike has been running really well since fitting the Remus system but could this be the cause??.......I have read that exhaust valves can be quite prone to overheating etc as a result of the bike running too lean but mine seem to be in good condition. I'm thinking that without the cat code plug my bike would have been running a little rich if anything....am I right?

Does anyone know why my bike may have failed in this way or has anyone had a similar experience? Are some pistons just weak?

To say that I am disappointed with the reliability of my 'bullet proof' stone age engine is a major understatement!

Fortunately I'll be able to get the bike back together as soon as I have traced some parts but I hate to think what this would have cost to fix at a dealers (£000's). If anyone has any good contacts for second hand or new parts it would be much appreciated. I definitely need a piston and cylinder.

I am highly hacked off and tempted to put it back together and buy a Honda!!!!

Den · Apr 4, 2004

There is a compete 1150 engine for sale on ebay at the moment.
I dont know if its any help or what its going for. Shitty luck

Fanum · Apr 4, 2004

Any chance of a piccy of the 'hole'?

Might well help the wrenchers here to identify the more likely causes.....holes caused by dropped valves are different from....er....other holes.

Eck, I dunno, just wondering if it'd help.

:confused:

Bad luck though...but its the first one I've read about here and most gripes get covered.....not even Maverick has holed his pistons yet so you MUST be unlucky!!!

StooL · Apr 4, 2004

The hole is on the outer edge of the piston at about the five o'clock position as you look at it. It looks like it has just melted through somehow??

Deadskin · Apr 4, 2004

Sorry Stool
I've been on many GS related sites but your the first i've
read about holed pistons,
Have you contacted your local bmw dealer or even bmw uk
they may well be interested.

Gates (2000 GS 16k

)

Greg Masters · Apr 4, 2004

StooL said:
The hole is on the outer edge of the piston at about the five o'clock position as you look at it. It looks like it has just melted through somehow??

Poor fuel quality and/or overly advanced timing can hole pistons, but in these cases the hole looks like it has be caused by a physical impact rather than the melting of the piston material.

Sounds like it might have overheated due to a weak mixture.

Next question is why was it running a weak mixture? You've mentioned Y-piece and exhaust can - they can both have an effect on mixture. If this proves to be the case, you've been very unluck as loads of bikes run this setup without damage - but it's one of the risks that you run.

Greg

carbold · Apr 4, 2004

knock

Sorry about ur bike mate...
Continuous knock can cause holes on the piston due to melting.
I think it'is one of the most common damages due to knock.
Motorworks should have some 2nd hand parts

Darth_1100s · Apr 4, 2004

Stool, just a question - where do you buy your fuel? I know that supermarket petrol has come under fire recently for "only just qualifying as petrol" Apparently it's been causing lots of problems for car engines due to it's very low octane rating.

Found this link: we never really know what we're putting in our tanks

http://news.bbc.co.uk/2/hi/uk_news/wales/2909259.stm

With running the Remus and Y piece set up, maybe it should be a lesson for us all to have our bikes Dyno'd after any interference or straying from standard. We could probably have gotten away with it on a carburetted bike, but with fuel injection and electronic engine managenent - grey area I'm afraid.

Hope you get it sorted soon

Dave.

(RIP) maverick · Apr 4, 2004

Fanum said:
....not even Maverick has holed his pistons yet so you MUST be unlucky!!!

I am sure if I can get the fukcer running again I can sort that odds out too mate!

(RIP) Mark Dilloway · Apr 4, 2004

Wierd - normally when an engine is running hot it's obvious - it just feels very hot just to be near it!! So many people are running Y pieces and the fuel injection compensates leads one to suspect something else. If it really was lean there would be severe loss of power.

It would have to be pinking really badly to cause the problems you have.

Dunno - sounds really odd to me.

StooL · Apr 5, 2004

Thanks for the info and suggestions...keep em coming.

I've got a bit more info now after visiting an engine specialist today. He believes that there has definitely been a mixture problem in the right hand cylinder. The exhaust valves are OK but they're showing a bit more sign of wear than the other side. The other cyclinder is perfect and this leads the guy to believe that the right hand cylinder has been running with a weak mixture. I am now in the process of removing the injectors to have them tested. With a bit of luck there will be a problem with the right hand injector and I will therefore have found the cause of this disaster (hopefully).

If there is no problem with the injector then I'll be rebuilding the bike with still no clue as to the cause of my cylinder trouble and this will obviously dent my confidence when taking the bike to Europe this summer. I don't fancy touring Europe in the back of a breakdown truck!

I never got any clues to this happening. As I said the bike was running really well, no sign of being down on power or running/ feeling hot. Therefore I'm thinking any problem with the injector must be fairly small and this problem may have been building up for some time. By fitting my Remus and probably making the bike run slightly weaker this may have been just enough to push it over the edge.????

As for the fuel suggestion, I do fill up at a Safeway at least once every three fill ups. I don't think it has been this but I'll be sure to avoid them from now on, thanks.

Greg Masters · Apr 5, 2004

I would find it very frustrating to have rebuilt the engine without getting to the root cause of your problem.

If you want to be sure of your bike for you forthcoming trip, I would suggest that you revert to the original exhaust system and then get the bike rolling-road tested to have the mixture measured when the engine is under load.

If that reads OK, then substitute your Y-piece and exhaust can and measure the mixture again. If it's gone weak - at least you know what the cause is.

Greg

StooL · Apr 5, 2004

That's a good idea Greg.

If you see a Remus and Y-piece for sale soon you'll know why. After coughing up for a cylinder and piston I'm f****d if I'm spending more cash on a chip!

adamski49 · Apr 5, 2004

Just and idea but one of the guys on the S forum blew his motor with similar results to you, i.e. just one piston holed.

He narrowed it down to the BB Power chip and a failed Lambda sensor. As far as I understand when the Lambda sensor fails the BM chip defaults to a 'get you home' rich fuel mixture - he concluded that the BBP chip didn't have this option unless it was set to the BM chip map - unlikely with go faster goodies.

Do you have a different chip (and failed Lambda) that could be the cause?

Adam

[Edit] Ok, just read you're last post - no chip then.

StooL · Apr 5, 2004

Yeh, no chip! I will have a look at the sensor though just to be sure. At lthe very least it'll eliminate another potential cause.

Still find it strange that the left hand cylinder shows no signs of weak running so I'm crossing my fingers for a good (bad) result with the injector.

ferguscawley · Apr 5, 2004

Stool

Could very well be a clogged or faulty injector. Could also be due to an air leak between the throttle body and the intake valves. Did you perhaps lose the little rubber cap thingy that fits over the port for balancing the throttle bodies ? - this would cause a weaker mixture on that side.
Just a thought thats all ..

Ferg

ferguscawley · Apr 5, 2004

The rubber-cap item I am referring to is #14 in the attached picture. I'm not certain if the 1150 has the same set-up or not but I would guess that it has.

Ferg

Paul Wakefield · Apr 5, 2004

I'm not certain if the 1150 has the same set-up or not but I would guess that it has.

You're right - it does have the same set up.

They got left off mine once after a service - boy, did it backfire!

Paul

StooL · Apr 5, 2004

I've just checked the bike and found all my rubber bits are present and correct!

Do any of the screws etc associated with this bit of the bike have any function in altering the mixture?

Injectors are both out and on there way to be tested, I'll keep you posted on the outcome.

Still waiting for a call back from a dealers for new part prices.....they better phone back or I'm definitely buying a Honda!!

ferguscawley · Apr 5, 2004

Stool

The only bits that affect the mixture there are the big brass bleed screws (#18 in the pic). However, these primarily affect the idle mixture and to a certain degree affect part throttle settings. Once the throttle is open say 30 %, these screws have little or no bearing on the overall mixture setting.
A badly balanced bike would affect the mixture though, but you should feel this imbalance when riding. Buy yourself some vacuum guages and check the balance regularly. I do. It takes 5 mins to do this.

Ferg

Major Piston Problem......help!

Registered user

Well-known member

Toubab

Registered user

Registered user

'Don't mess with me' Member

Active member

Darth_1100s

Guest

Well-known member

Active member

Registered user

'Don't mess with me' Member

Registered user

Registered user

Registered user

Well-known member

Well-known member

Attachments

Well-known member

Registered user

Well-known member

Similar threads