I recently started my bike and heard a heavy clatter from the front of the bike.

It went away after a few moments, but whilst riding I can now hear a noise from the front of the bike.

Hey ho,...time to look at the chain. Never done one before, so new kit ordered.  Do not want to go in there again .

Everything looked good, but I can press the tensioner down by around 4mm, not sure if that is normal.

perhaps the chain slapping around would account for the noise. 


The only other reason might be the radiator cowl seal on the bottom is badly worn, missing, which had been 

rubbing on the timing cover.







Thanks for any replies

Bob

Not really normal for that 4mm but not to be unexpected either. The holding mechanism for those tensioners is not good. Any time I get in there I put a K75 tensioner in as they have a far better way of holding the tensioner up till oil pressure comes up. Please don't ask why BMW made a better tensioner for the K75 then didn't carry it over to an upgrade on the K100 because I will have to say "stuffed if I know that's BMW for you".

Thanks Rick,

I think I may have inadvertently brought this upon myself.

After doing my rear main seal , I refilled the engine oil  ( didnt swap the filter ) 

and started the bike up and heard the noise from the timing cover as soon as the motor fired up.

I have a feeling that I forgot to disconnect the fuel pump and prime the oil pressure before starting.

 Should this  have caused the tensioner to fail ?

the noise was very loud  as if the chain was slapping around,  and then went quiet although I could hear noise 

whilst riding.

I will remove the tensioner and split it to have a look 

How does the K75 unit differ in design from the K100 ?

Is it possible to buy a new tensioner , or is it e-bay 

Thanks again 

Bob

im going through the same issue on all of 4 x camchain tensioners for early k100 s ...
the pin inside the tensioner piston wears along is length (sides ) that contact the snail cam guide
+ the sharks tooth gear wears against the square rivet type retainer , and the sharks tooth teeth wear on the interference cup inside the tensioner base housing ..

possibly the easiest way out might be the k75 tensioner ...but a bit unaware if the lobe- projection  on the k75 tensioner will fit in the same place and not interfere with the timing cover  

any feedback Rick ?

I cant see any reason a K75 tensioner wouldn't fit after all the castings are the same.
The K75 have a small ratchet that wont slip backwards like a worn K100 tensioner does.  I would not be concerned about doing damage in the short time it takes to get oil pressure up. If the chain was slapping about like that for a while there would be damage but not in the short term.
Motobins have them 24 quid

Removed the old chain,  length was okay but bit bendy in the middle. on 60,000 miles

All tensioner rails were good, but have new ones now.



White cable tied the sprockets only to find Mr BMW didnt leave enough room at the top of the casting to pull the chain off. Had to loosen sprocket off its cam .. Black marker  on end slot of cam to casting...

I suspect it might be easier to ft the chain and time it up with the top sprocket loose.

The tensioner cam look suspect. There are marks on the sprung piece which suggest wear.

I left the spring off, and inserted the top piece down into the bottom casting, and pushed hard onto the cams.

I then judged how far each rachet movement gave me.

Most rachet movements were small and equal, but some gave me a lot of movement , confirming there is wear , enough to cause loss of tension. 

The oil hole at the top was clear , as was the inlet oil hole.

Another tensioner needed.

I havent seen any on the sites, I would have thought it would be included in the kit.






The k75 tensioner has the spigot for the oil feed.

The oil recess on mine is 9mm wide and 17mm deep, with the oil feed coming at a right angle from the left side

 when viewed from the front.





How do you delete an unwanted foto ??

Ah well the search for a tensioner resumes.  VERY DISAPPOINTING BMW...

At least I have a box from motoworks with a Front master cylinder seal repair kit, and some new braided hoses to fit..

She may not look very fast on the bench, but at least she will stop on a sixpence .....

Bob

Just checked BMW OEM site and for part number 11311464051

they quoted £ 150.00


Wow...


wow....

Bob