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BMW C650GT Cam Chain Tensioner replacement instructions and parts

Several have reported the same thing happening, but that their engine WAS NOT damaged. Although it would not start because the engine went out of time, they were able to put it back into time by moving the camshafts back to where they should be, install a new tensioner, and the engine came back to life as if nothing had happened. So, in case this happens to anyone reading this thread, it is definitely worthwhile to double check before disposing of the motorcycle or engine. It may be salvageable! BMW dealers likely don't know about this possibility and so will not suggest even trying.
 
I bought a 2013 C650 GT, only 750 miles. I only learned about this problem from reading the blogs. I called BMW and they said my VIN number was not part of the recall. Only the brake line recall was listed. I knew about that one. They forwarded me to the NTSB, they said the same thing. The NTSB guy said maybe the tensioner was replaced by the first owner. Wouldn't there be a record of the replacement being done? This problem has got me a little freaked. Any BMW guys on here that can answer this? Thanks
 
BlkBlt said:
I bought a 2013 C650 GT, only 750 miles. I only learned about this problem from reading the blogs. I called BMW and they said my VIN number was not part of the recall. Only the brake line recall was listed. I knew about that one. They forwarded me to the NTSB, they said the same thing. The NTSB guy said maybe the tensioner was replaced by the first owner. Wouldn't there be a record of the replacement being done? This problem has got me a little freaked. Any BMW guys on here that can answer this? Thanks
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Best, and cheapest solution will be to modify your tensioner into a mechanical one that does not require the spring-loaded mechanism to operate. Then, once per oil change, remove the side panel and re-check the tension of the mechanism to ensure the chain doesn't loosen. Consider it just another step for the 6,000 mile service interval. The 'hydraulic' tensioners are a much later addition to the engine, and the pieces cost about $500 total. The unfortunate thing about any tensioner that comes from BMW on this engine is that they all move constantly in some way or another, so they can fail as they move. It would be better to make a tensioner that does not free-float or move, and have a maintenance item at the 6000 mile servies to adjust the tensioner using a certain procedure. Unfortunately BMW is very proud of their designs and mechanical engineering expertise, and just refuse to see the problem and have every excuse lined up just in case.

The way I modified mine was to disassemble it, take a 6mm bolt and modify the head to a blade shape with minimal height so it did not tolerance stack the actual winding mechanism, that would mate with the slot in the top of the spiral tensioner. Grind away the last 6-8mm of threads right below the head of the modified bolt, so that it spins freely in the housing when inserted from the bottom, and make sure it does not bind. Then insert it, add a nut to the top, grind a slot in the end for a small screwdriver so you can set tension with it, and add the internals making sure that the spiral extender mechanism mates with the blade on the modified bolt head. After that, wind the mechanism tight, using the newly installed pieces and lock the lock nut, to keep it from spinning and expanding, then install in the engine. Unlock the lock nut and the spring winder will extend the tensioner to the proper length. You can set a preload with the slotted end, a few times then let it relax and find it's own place. Once it's set, tighten the lock nut and you are done. Every 6K miles loosen the lock nut, rotate the mechanism about a turn out, then in, to reset the pre load, and retighten the lock nut.

You'll never have a failure if you make it a mechanically set and locked unit, and it only takes about 2-3 hours to modify the stock unit.
 
Thanks guys for the input. I replaced a cam chain tensioner on my old Kawasaki Vulcan that probably took me 10 mins. I was a spring load type. This manual adjust type is interesting. I'd probably go with the Ebay one. How would you know when you have it set properly? Not too tight or too loose?
 
BlkBlt said:
I bought a 2013 C650 GT, only 750 miles. I only learned about this problem from reading the blogs. I called BMW and they said my VIN number was not part of the recall. Only the brake line recall was listed. I knew about that one. They forwarded me to the NTSB, they said the same thing. The NTSB guy said maybe the tensioner was replaced by the first owner. Wouldn't there be a record of the replacement being done? This problem has got me a little freaked. Any BMW guys on here that can answer this? Thanks
Click to expand...
Just go ahead and change it out with the mechanical version it's available at bmw cars dealers for that ugly electric bmw car the small square one. Not a difficult job. Just need to remove the palstics, but good to learn anyway.
 
I've also opted to stay with the factory original part in my last replacement. As wofatchin notes, it is relatively easy to do. The only thing that is important though, is to have an ear for when the BMW part inevitably starts to fail again, so you can replace it before catastrophy strikes. Me I can hear the difference in the engine sound but not everyone has that mechanical ear.
 
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