[Patrique83]

I finally got around to renewing my camchain at 59000km.
The chain has lengthend by 0,5cm.
Not that i was expecting it to break, but since i am already measuring the valve clearance, i decided to change the chain and sprockets too..... €180 euros.

Warning: From late 2006 onwards, the chainsprocket on the crankshaft is a pressed fitting. Check your reprom carefully. Without a puller you wont get it off/on.
Also, the „new“ chain and sprockets have a slightly different lobe on the gear teeth.
So keeping the old cranksprocket and just replacing the camshaft sprocket won‘t work.
Both need to be replaced. See photo.

 

[Douglas M]

Thanks for the info :thumb:

 

[Capt howdy]

Thanks for the info Patrique. I was considering just changing the cmshaft sprocket on my K12. How did you find out about the revised profiles? This from Motorworks

A kit comprising the timing chain, the crank and camshaft sprockets.

Please note: this kit applies only to bikes produced before 11/2006.

Bikes produced from 11/2006 use the following;

11317707207 Timing chain
11317701209 Camshaft sprocket

There is no separate crankshaft sprocket available for bikes produced after 11/2006.

It looks like they use the same crankshaft sprocket

Is the new crankshaft sprocket easy enough to get off and back on? One consideration that has me a bit concerned is when the timing marks are aligned with the top of the cylinder head, how is the chain fitted to ensure that it is tensioned on the non tensioned side and that as well the teeth on the sprocket align with a gap in the chain and not a pin. Thanks for your assistance.

 

[Beech]

Good call. That is quite a bit of difference in length for a short chain. Timing was way off. I'm sure it will run better. Try to stay out of that 10,000 rpm range.

 

[Patrique83]

On the camshaft sprocket are 2 screws and a little centering pin. You remove the first screw, then rotate the crankshaft (the cam will still turn with only one screw still in place and the little centering pin).

After turning the crank, align the two —— on the camshaft gear with the top of the cylinder head.

Insert the crankshaft locking pin (BMW Special tool)

Now you can remove the second screw on the camgear.

Remove the hydraulic tensioner.

Once the tensioner is out, the chain becomes loose enough to remove the lower rail.

Take off the camgear including the chain.
Both will slip a bit downward and then you can undo the chain from the camgear.
Pull the chain out.

As long as the crankshaft is looked in place, and you dont move the camshaft everything is ok.
Just check that the —— marking is lined up to the cylinder housing and the centering pin engages the camshaft.

Slide the lower rail back in, and install the tensioner.

 

[Capt howdy]

Thanks for that Patrick. What I’m trying to ask (not very well) is how do you ensure the non tensioned side of the chain is correct. If you have the marks on the cams lined up and a tooth on the chain matches up with tooth on the sprocket and you have to slacken the chain to get the tooth on the chain to line up with the gap on the sprocket will the non tensioned side of the chain still be ok. Is the chain the correct length for this not to be an issue? I have the reprom CD and special tools.

 

[Patrique83]

Once the crankshaft is locked in place with the locking tool and the two markings from the camshaft (the U and —) are lined up then you can remove the chain tensioner and pull out the lower guide rail.

The camshafts wont move by themselves, even when pulling off the chain sprocket.

The chain sprocket has also two ——.
When the U and — from the actual camshafts are lined up, the two — — from the chain sprocket will be lining up with the top of the cylinder head housing (where the chain/rails go in)

When you open it up, it will be much easier to understand.

As long as the markings are where they are supposed to be, there is no way to fuck this up, trust me. 🙂

 

[Capt howdy]

Thanks again Patrick. What I’m after though is how is the correct tension is set on the non tensioned side of the cam chain. Is the chain of the correct length so that once the sprockets are aligned, the crankshaft locked and the chain fitted it can only be at the correct tension on the non tensioner side ie the front of the motor. Is it possible for the chain to be half a tooth out and therefore needs to be loosened to make it fit the sprocket or does it all line up as it should. I’m sorry to make this so elongated but as I said I guess I haven’t explained myself very well.

 

[Patrique83]

The upper rail will pushes down on the chain already while installing it (the chain + camsprocket), and once you slide the lower rail in the chain wont have any slack left.

There wont be any movement from the camshafts.

I did take out the locking tool because i couldnt get the little guide pin to insert into the camshaft (to tighten the first bolt)
It was off by about 0.5mm.
Thats because the old chained had the camshaft positioned a bit off, being longer.

You wont be turning either cam or crank so far that it will cause an offset in valve timing.

 

[Capt howdy]

Immense Thanks for your patience Patrique you’re a great asset to this forum 👍

 

[Mattias_r]

Patrique, would this procedure be the same on the K1300?
Looked in the manuals and this is not even described in the manual for the k13, only in the k12 manual.

 

[Beech]

You are not able to remove the drive sprocket from a K13 crank. No replacement sprocket is available. Only chain and the driven sprockets on the camshafts. I did this job at 75K miles on my bike and it was too early after close inspection.

 

[Mattias_r]

So on tge k13 the chain and cam spricket is the only replaceble parts? Maybe better off going with a manual tensioner and new guudes then? Or a new oem tensioner and guides? Have got a slightly increased noise when letting go of throttle, even with the clutch pulled, so it is the chain.

 

[Douglas M]

Thanks for the information

 

[Beech]

First I would try the rebuild kit for the factory cam tensioner

11 31 7 705 460​

SET: O-RING SET​

​

1​

$13.98​

You need a box end E8 torx wrench to remove and replace it. Be sure to loosen and tighten both bolts evenly as it can bind up. This generally helps. I replace mine about every 3 years. As mentioned, when I replaced my cam chain at 75,000 miles (110,000 K) I could see no wear.

 

[Mattias_r]

You dont happen to know the dimensions of the orings?

 

[Beech]

No, one small that goes inside the piston assembly and a larger one that seals the body to the engine case. You could remove it and measure them or take them to your favorite shop. I know the price is steep for two orings but that is bmw for you.

 

[Mattias_r]

Talked to my dealer today, he recommended first trying the O-rings, and if i still had a rattle and i needed a new chain and/or tensioner, he would deduct the price of the o-rings. Think they were €14. In their experience when first getting rattle, O-rings, next time, new tensioner, if it happens again, new chain, sprockets are normally fine. The chain was cheap, i was ready for a shock but it was just €90.

 

[Beech]

Good choice. The metal of the tensioner is good, the O-rings wear out. I think I would change them every 2 years or 30,000 kilometers.

 

[Mattias_r]

Will meaure the new rings when they get here and then have them sourced from my local supplier. Viton/fpm seals are cheap, as long as one keeps bmw away from being supplier. Bmw wants €7/ piece, my local supplier wants €1,45 for the big one and the small fall in a pricerange of up to €1. So €2,45 instead of €14. The savings will go towards fuel instead, but that is more fun than giving it to bmw.