Right hand cylinder destruction

[Ditchdablade]

A friend of mine has a GS 1200 hex head that has just destroyed a right hand cylinder. Piston has hit valves and is a right mess. We are looking into why this has happened. Has anyone got any known issues that would cause this? Cam chain is fine.
My assumption is that valves have been adjusted wrong. Or the valve has stuck open?

 

[Pukmeister]

What year is it?

Early hexheads were prone to snapping off valve heads from the thin walled sodium filled valve stems, it happened to a mates 2005 GS as he was riding it to the dealers to hand it over in part-ex. For some reason it was always the right hand cylinder.

Theories vary from incorrect valve clearances, poor materials and a weak mixture.

 

[JohnnyBoxer]

A friend of mine has a GS 1200 hex head that has just destroyed a right hand cylinder. Piston has hit valves and is a right mess. We are looking into why this has happened. Has anyone got any known issues that would cause this? Cam chain is fine.
My assumption is that valves have been adjusted wrong. Or the valve has stuck open?

Steptoe will know
I seem to remember that he said 1200’s (air/oil) had a propensity to go bad on right pot, due to valve snapping

 

[Ditchdablade]

Steptoe will know
I seem to remember that he said 1200’s (air/oil) had a propensity to go bad on right pot, due to valve snapping

I take it , it’s a rebuild on the right hand pot (duh obviously) but look for secondary damage in the whole timing chain area, con rods anything else?
I was looking for some kind of primary failure and it sounds like valves being crappy with probably bad valve clearances that impacted piston.

 

[Ditchdablade]

What year is it?

Early hexheads were prone to snapping off valve heads from the thin walled sodium filled valve stems, it happened to a mates 2005 GS as he was riding it to the dealers to hand it over in part-ex. For some reason it was always the right hand cylinder.

Theories vary from incorrect valve clearances, poor materials and a weak mixture.

Imagine your surprise when I tell you it’s an 05 !!

 

[Steptoe]

Steptoe will know
I seem to remember that he said 1200’s (air/oil) had a propensity to go bad on right pot, due to valve snapping

Every one I’ve seen (and there’s been quite a few) have dropped a valve on the righthand side.. I’ve no idea why it always seems to be the right side.

Here’s a few I did earlier, said in my best blue Peter voice.
Here’s a few pictures from my extensive gallery of horrors
That’s my screwdriver pointing at the valve embedded in the piston in the first picture, incidentally that bike was delivered to me from France as it worked out cheaper than the French main dealer wanted to charge to repair it .
And a nice new piston from Germany for a 1200s

 

[Ditchdablade]

Have the valves now been sourced as better replacements? Or are we still on like for like ? Crappy broken valves out, (well they are a million pieces!) New, but still crappy valves back in a new head? Lets hope not

 

[Pukmeister]

I can’t answer that but you could surf through some online BMW parts fiche such as MaxBMW/RealOEM and compare model year part numbers for revisions.

Note from Steptoes pictures above that yet again it’s an exhaust valve failure in a right hand cylinder.

Exhaust valves run hotter than inlets for obvious reasons, they dissipate their heat into the head casting each time the valve head closes onto its seat.

If valve clearances are insufficient the valve cannot seat properly and heat cannot dissipate into the head, leading to weakening of the stem area where its friction welded to the valve head.

Similarly, if the engine is running excessively lean it runs excessively hot. I’m no fan of modern lean burn engines, a slightly higher air/fuel ratio is better for both power/smoothness/cooler running.

Once repaired with perfect valve clearances (or even slightly bigger on the exhaust valve side) I would consider getting it to a rolling road bike tuner who can measure and tune the ECU air/fuel ratio when under load on the dyno. No doubt the hilltop fans are about to jump on this thread, my experience with hilltop was that he wouldn’t measure my AF ratio so I’d find somebody else that does.

 

[botus]

even twin cams will drop a valve from 80 to 100k miles (need to think of it as part of a sensible extended service schedule) - of course how hard you rip it will be a factor - never go over 4k I doubt it will play up, rag it to 8 k everyday....

 

[DrFarkoff]

even twin cams will drop a valve from 80 to 100k miles (need to think of it as part of a sensible extended service schedule) - of course how hard you rip it will be a factor - never go over 4k I doubt it will play up, rag it to 8 k everyday....

BOLLOX!!! DICK!!!!

BULLSHIT CALLED AGAIN!!!!

 

[JohnnyBoxer]

BOLLOX!!! DICK!!!!

BULLSHIT CALLED AGAIN!!!!

Don’t sit on the fence

 

[DrFarkoff]

Don’t sit on the fence

@JohnnyBoxer that guy, has given people so many bits or WRONG info

You and I may disagree occasionally but what you post is usually "spot on" info

That guy likes to pretend he knows it all!

I have NEVER heard of a TC dropping a valve ever in my "trade" experience since 2003 until I basically decided to focus on my own stuff a couple of years ago

 

[DrFarkoff]

Actually that needed Clarifying above !

I know TCs did not come out until 2010 in case some one starts to Nit Pick !

But still never heard of one drop valves in the 15 years since

 

[TLSgazza]

Actually that needed Clarifying above !

I know TCs did not come out until 2010 in case some one starts to Nit Pick !

But still never heard of one drop valves in the 15 years since

I guess my single cam 2006 GSA is due to drop a valve at almost 150.000 miles.

 

[DrFarkoff]

I guess my single cam 2006 GSA is due to drop a valve at almost 150.000 miles.

Fuck Sake Man Don;t be telling people that

I am actually thinking he may be an AI bot ...

Anyway Keep them Loose
Service it every 6000 miles
Decent Oil Good Filters

But I guess everyone still has a ways to go to catch Hank over 450,000 miles on his 1150 I think

 

[snelly]

Every one I’ve seen (and there’s been quite a few) have dropped a valve on the righthand side.. I’ve no idea why it always seems to be the right side.

Here’s a few I did earlier, said in my best blue Peter voice.
Here’s a few pictures from my extensive gallery of horrors
That’s my screwdriver pointing at the valve embedded in the piston in the first picture, incidentally that bike was delivered to me from France as it worked out cheaper than the French main dealer wanted to charge to repair it .
And a nice new piston from Germany for a 1200s

View attachment 400141View attachment 400142View attachment 400144View attachment 400145View attachment 400146View attachment 400147View attachment 400148

That's a fair trail of destruction;; you say it's always the right hand side; the side stand is always on the left; what would be the chance of oil draining from that side whilst parked or summat; i know it's far fetched but it seems to be the only thing in common.

 

[dmsantam]

I realise this thread is a year old, but thought I'd add my 05 had the same issue but on the left hand side. I bought second hand cylinder, piston and head from a low mileage bike, along with new head gasket and gudgeon pin circlips, and she's back running again. had 109000km on the clock when it happened

 

[snelly]

I realise this thread is a year old, but thought I'd add my 05 had the same issue but on the left hand side. I bought second hand cylinder, piston and head from a low mileage bike, along with new head gasket and gudgeon pin circlips, and she's back running again. had 109000km on the clock when it happened

65000 mls is just run in;; i notice your Aus have to be a compleatly different side to us ;

 

[squibb34]

When I had the inlet valve head drop, on the wife's then Kawasaki ZXR400, the dealer who supplied the parts suggested that I should replace the cam chain as a precaution. As luck would have it, our valve debris had jammed itself up the inlet port promptly (tiny valves of course), so had wrecked the inlet valve guide but did minimal damage to the piston crown.

It was soon back up to revving it's nuts off - the power came in around 9k, right up to just short of the 14.5 k redline.

 

[Engineer]

I did 50k+ miles on my 2005 hex head in 5 years, it never dropped a valve.