R11XX cam chain tensioner - catastrophic failure?

[hcmiller92]

I was reading the latest copy of "Backroads" magazine the other day and the publisher, Brian, was discussing the demise of his 11XX GS as the result of a failed cam chain tensioner.

 

The story goes that he rode his bike from Lake George's Americade to Troy, NY after the engine stopped, accompanied by a boom. He was able to restart the engine and ride to Max's where he was told the fault was a failed cam chain tensioner and that it was "fatal." Ho rode it back to Lake George and the bike coughed its last breath as he pulled into the parking lot, with 97,000 miles, never to start again. Dead.

 

I don't get it. Why would the bike be unsalvageable? Why would the engine not have been rebuildable at the time he pulled into Max's? Seems to me, any engine can be rebuilt. There was no mention that pistons blew or cases split or anything else that would indicate the engine was unrepairable, let alone the bike was ready for the junkyard.

 

I now have a hex head, but it's still the same 1950s technology of the oilheads and am perplexed, confused - and a little pissed - to think that such a relatively small issue would render an expensive BMW motorcycle junk.

 

Can anyone shed some light on this matter?

[Stan Walker]

Let me see now.....

 

Pieces deep inside the engine have broken, then he rides it for ??? miles, finds out what the problem is, then he rides it for some ??? more miles.

 

Not a real smart rider IMHO.

 

The shattered plastic parts from the cam chain guides can block the oil intake and that causes oil starvation to the crank and other places. The end result can be a major rebuild including a new crank, new main bearings, new chain guides, and a ton of labor. The engine is probably rebuildable, but the cost likely exceeds the cost of a used engine.

 

Stan

 

 

 

 

[skinny_tom (aka boney)]

The older 11xxGS tensioners were different than the new 1200s. There's also an update kit for the older bikes that can be installed in about an hour. Why anyone with an older bike doesn't do it (and why I waited until 66,000 miles myself) I cannot say.

 

What I can say is that if my bike stopped after a "boom." I think I'd park it and find a way to get it where ever it needed to be without inflicting further damage by running and riding it.

 

It was quite possibly an easy repair when the engine stopped. Starting and riding the bike afterward is what turned it "fatal."

[smiller]

Also note that cam chain tensioners are not a very common failure item on the oilheads, in fact quite rare.

[T__]

hcmiller92, the thing I have to wonder is IF it really was a cam chain tensioner? Maybe a cam chain guide or something else cam chain related but a tensioner is difficult to believe.. Those things don’t usually suddenly fail,, they bleed down & get noisy & allow chain noise but catastrophic failure is not something they do..

 

I guess I’m not sure we are getting the whole story here or it is somehow not the entire story.. Once the engine went belly up how the heck could anyone tell it started with a cam chain tensioner?

 

On the BMW boxer something as simple as turning the engine backwards with a loose cam chain or unpressureized tensioner could damage a cam chain guide & lead to cam chain problems

 

If you are worried about your engine then just Google all the BMW boxer engine failures related to cam chain tensioners (my guess is the only one you will find is your posting here)..

 

Twisty

 

[smiller]

I think what he may mean is cam chain tensioner guide. But even that would raise a lot of questions in relation to the above story and I'd have to agree that there must be some missing pieces (no pun intended) here.