Left R12S camchain tensioner = kaput

peter f · 07-24-2008, 07:42 AM

Well friends,

Today (all of a sudden) some "rat-rat-rat-...-repeat" noise was coming from the left side of my boxer. Hmmm...looks like (a) some alien (extra small size) creature was in and/or (b) that camchain tensioner spring - see attached (a known "BMW-uber-alles" failure here in Greece) was kaput (could be a camchain tensioner failure? why not? it's made in China anyway...).

Dealer > warranty check > spring ordered (DHL) > sorry Sir > not until tomorrow > have an espresso (make mine double).

PS: imagine the camshaft pinion "jumping" a tooth (or two)...MAMA MIA!.

PS: bike is a 6K miles bike (immaculate condition).

Moral: BMW-uber-alles?

Bob Hancock · 07-24-2008, 09:10 AM

erm.....so did the chain jump a tooth or was just preparing to?

bigscience · 07-24-2008, 10:52 AM

so long as it's really the tensioner spring I'd say you're in good shape since that's an easy 10 minute fix. if, on the other hand, it's the plastic slider (parts 2,3, or 4 in the diagram), then it's time for your tears. for that means splitting the case to effect the repair, etc etc. and that means no bike for a long while. the bike has to be completely disassembled!

bueno suerte
car

2wheelmike · 07-24-2008, 11:28 AM

Quote:

Originally Posted by peter f

Today (all of a sudden) some "rat-rat-rat-...-repeat" noise was coming from the left side of my boxer. ]

Was it making this noise continuously or just some of the time (like on decel at a certain RPM)?

AntonLargiader · 07-24-2008, 01:56 PM

Hopefully he ordered the #15 piston and not the #14 spring. There isn't a spring on the left side.

peter f · 07-24-2008, 08:52 PM

Quote:

Originally Posted by 2wheelmike

Was it making this noise continuously or just some of the time (like on decel at a certain RPM)?

Well

"rat-rat-....repeat" started (out of the blue) and the machine was making the noise continuously regardless rpm (rat "frequency" was rpm related). You remember the plastic cards that we(?) used in our bicycles when kids? (anyway I used them).

At the time of writing it's not clear what exactly the damage is (I mean, if it affects the plastic tensioner thing as a whole etc etc etc). However and judging from dealer's "easy" reaction (that means he was quite familiar with the problem) I do suspect piston,spring related stuff.

Dealer said that the thing hasn't jumped a teeth.

I said : what about the "broken" little things inside the motor? Dealer said : have a double espresso...

The whole case puts the obvious question: what about hydraulic camchain tensioner(s)? - "BMW-uber-alles" bla bla bla

markjenn · 07-24-2008, 09:41 PM

Dunno where you're going with this. They sometimes fail, you put a new one in, and you carry on.

- Mark

peter f · 07-25-2008, 06:44 AM

Last update (bike at home right now)

Guru said that was a "seized" piston. I said : how's possible? you mean some tiny metal debris (new motor) found his way to that piston and blocked it? Guru said : erm...they always do that Sir. I said : how nice and pretty...what if the camshaft had jumped some stuff?

Guru said : Ah this...2650+ Euro work that one. But why bother? your bike has 1 year more warranty to spend.

peter f · 07-25-2008, 06:51 AM

PS: 6K miles bike > failures so far

1. OEM crap battery (replaced with another crap)
2. Left Idle actuator (replaced)
3. see 2 (replaced)
4. find neutral when down shifting > impossible (unresolved)
5. that tensioner piston (replaced).

Moral: long is the Path (and hilly).

Fenring · 07-25-2008, 12:26 PM

Tough luck man.

Mine's just over 10k miles and I've had nothing but smooth performance from it so far all year round, regardless of the outside conditions. On the other hand it could be because I ride as slow as my grandma.

I did have one problem with it from the start, and it was faulty turn signal switch, that caused the computer to constantly turn on all four turn signal lights, which was very annoying, what with everyone in traffic honking at me hey-dude-all-your-lights-are-blinking like, but that was replaced in one afternoon under warranty, so I never gave it a second thought.

Bob Hancock · 07-25-2008, 12:33 PM

Now at 18,000 miles my bike is doing fine, knock on wood. I had a small paint issue but it was resolved by the dealer. Sorry to hear yours is breaking down. They shouldn't do that.