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Discussion in 'Parallel Universe' started by Dieselboy, Sep 22, 2011.
https://www.motomike.eu/pl/article/548568/ Maybe I made wrong translation from polish
I had this cam chain in the first engine. He worked 40,000km and it was all right. Now in the second engine I also assume D.I.D.a
Ahhhhhhhhhhhhhh got it!
I think here we would call it a "timing" chain!
Any diameter deviates from the oryginał? I thought there is no replacement. I've read somewhere that this chain is made for different tooth profile.
Morse says that for F800 is only 98 XRH 2015 and DID not have any equivalent.
However I did not test it myself so maybe DID SCA-0412 is ok for F800. I have SCA-0412 dimensions so I will measure my new original.
It's rather new chain and it is suggested to f800. It works, it is tight. We will see.
I just replaced my cam chain. The steps i considered as diffiicult like grinding open the old chain, feed through the new one and the riveting worked suprisingly smooth.
But I made a ridiculous mistake: For finding the TDC I orientated on the E/I marks of the camshaft before dissasembling any relevant part, like I did several times before when inspecting the Valve clearence. As i expected i found a very little[FONT=Tahoma,Geneva,sans-serif] [/FONT]machining mark (hard to describe) on the crankshaft in the light of my Flashlight i considered as TDC.
So I went on with the known working steps. After feeding through and riveting the new chain I locked the Crankshaft on the machining mark I considered as TDC and installed the new camshafts. I found them to line up quite parallel to the engine case. I rotated the Exhaust camshaft one tooth in both direction to make sure I am Right but no improvement, so i returned to the original position. As I had a new chain and the camshafts where not screwed downd by the camshaft holder totally i considered it as good and went on with the steps.
For inspecting the Valve clearence i rotated the engine two times, happy About my perfectly tensioned chain now and stopped at the X/N mark. These where in General at the Right Position, but too far of from being parallel to the casing.
Now I begann to worry. And as I rotated the engine back to E/I mark I found in the flashligt shine Right next to my wrongly considered TDC the REAL, majorly milled TDC mark!
Man, I had no Picture of it.
(I even joked to myself About the austrian rotax guys not installing a proper TDC mark at an engine...)
Now sweating, i locked at this correct TDC Point the crankshaft and found the Exhaust camshaft to be of one tooth!
So i made the steps to turn the camshaft one tooth, and now, both marks E/I and X/N lined up perfectly parallel to the casing.
Long Story short: My chain at 135.000km was so stretched that i locked a slightly wrong TDC mark which lead to install the Exhaust camshaft one tooth off wrong. Stupidly enough i rotated the engine several times by hand at this missalignment before my correction.
Do I have to worry about having damaged the valves??
Probably not rotating by hand and only one tooth off. Running it there's a risk of burning valves but one tooth off there's a good chance it wasn't far enough off to touch a piston.
Easy check is a compression test but I'd be thinking I dodged a bullet there.
All i can tell is that by Manual turning it seems to compress like it used to before.
Overall, i am impressed of the great conditions the mechanical parts are after 135.000 km. Every Surface of the camshafts, bearings, Levers looks like it seen Maybe 5.000 km. I can not Imagine a engine beeing able to look better after such a distance.
It is fine. There's not enough difference in one tooth to have caused any problems. Good job on recognizing the problem before continuing.
Thanks for saving my Weekend
Sorry to barge in with this, but there is a thread here somewhere where an inmate is doing some engineering / reverse engineering of the cam chain tensioner assby.
Damned if I havn't lost the thread ...
Can someone post a link?
I don't know which thread you referring to but my reverse engineering is in process. So far I have made 2 inner pistons with to different sizes from 40H steel and I hope I will do the hardening of those samples next weekend.
Yes! Thank you ... I thought you had started a separate thread, but ... it's right here
I'll probably open a can of worms here, but I have recently installed the manual camchain tensioner offered by Southern California MotoWerks. At $160 it's a pricy bit, but very nicely made. (I will submit that at that price it should come with a new crush washer and at least SOME word of instruction on installation and setting tension). At that price I could have thrown several more OEM tensioners at the problem, but I wasn't inclined to do that.
My bike's a 2009. The original tensioner failed right after 30K miles and I replaced it with the BMW part. When that second one began to fail at about 60K miles, I was considering building my own manual tensioner and was happy to find that someone else had already done that work for me, and done it very well. This is a far superior piece to the ubiquitous APE brand tensioners I have installed on many customer bikes. (APE does not make one for the F800). The bike is now quieter than it has ever been in it's entire service history. This engine had always made a terrible rattle on start-up, and more camchain noise while running than I think it should have. Several years ago when BMW was offering me cash for my bike, the dealership mechanic looked it over and commented on the top-end noise. The shop owner and lead mechanic where I work now gave me constant low-level grief about the rattle. Now everyone's happy except those who don't trust mechanical tensioners. Me, I'm willing to agree that a perfectly working hydraulic tensioner would be preferable, but with the poorly functioning OEM unit my only other replacement choice, the bullet-proof reliability of a manual one was attractive. I'l report back if I ever have reason to regret my choice.
So if your experiment is a success...
Could one of your machined and hardened pistons be substituted in the OEM tensioner assembly?
Definitely $160 is not a bargain.
I know that it will be a problem for you but any photos of the manual camchain tensioner would be great for engineering purposes.
I honestly don't know yet.
Just today I finished first of two prototypes. Hardening process was made in a temperature controlled camber in argon environment ( I used low carbon 40H steel so inactive atmosphere where needed).
All the process was made with a help of one of the best blacksmith in Poland.
It is only 10.79mm but I will try make 10.80mm next time.
Compare this to the original.
It is design to be fitted in original outer piston. I hope I will test it this weekend.
Thanks for the update!
Best of luck with testing!
Here's a picture of the Southern California Motowerks tensioner. I took this shot right before I put it in, to share with the friend who was going to help me make one. There is a hex socket in the threaded end of the central rod.
Thanks for the pic. It is a fair simple design. How did you set it up? What makes you think that it is in a good tension position?
If it is better (less noise) that only prove my theory: "stiffer tensioner - better tensioner"
Wacholek, if you produce these in any type of volume count me in as a +1.