Hi again, riding last year, I noticed that the engine at idle, and even through the rpm range, I was getting a momentary hicup, the engine catching as it were. It sounds mechanical, so I've taken the timing cover off to look at it. I notice that when I turn the engine by hand (counterclockwise) that the timing chain tensioner is backing off or compressing. I know that with the engine running, oil pressure is supposed to keep it tight, and I'm thinking that the ratchet in the tensioner to keep it tight is worn out. (although it doesn't look worn excessively) There's about 60k miles on the engine that I know of. Has anybody run into a similar problem? As long as I've got it open I'm leaning toward replacing the chain, tensioner and guides but would like to know if I'm on the right track. Thanks for any input
Brickee

when i did mine .....there was in fact no oil presure involved at all ..(early 86 model but with 16 tooth final drive spline so assuming this was still in the swap over of parts era ...before the mainstream 86 models started )

what in fact was installed was a saw toothed disc mechanism driving a snail cam for the tensioner

i found mine did a smilar thing brikee

i disassembled it ..cleaned it up and reinstalled it after i was happy that it seemed to work properly

but i think i will have to revist this in the future ...just have to find a suitable replacement part before then i think.

hope that helps mate

What year is your bike Brickee? Early K cam chain tensioners didn't have the rachet mechanism in them, relying only on oil pressure. You can replace the early part with the later part. It is a direct swap. Be careful you don't skip timing turning a lose cam chain, not that I know anything about that mind you ..... Just check the timing marks carefully before going forward. Just saying .....................

Wow, fast responses. The tensioner I have is this

I've noticed that there's quite a bit of play(rotating movement) in the disk ratchet on the snail cam. Thanks charlie99 for identifying that.

Also while there is an oil port, it's for lubrication and not tensioning. It looks like it's the 2nd gen tensioner.
In the mean time, I've stripped out the torx bolts holding the tensioner between the cam sprockets. So tomorrow I'll drill them out and replace with allen bolts.
Thanks for your help guys.
Brickee

Oil pressure does hold tension on the chain while the engine is running and the purpose of the snail cam is to hold the chain in a very close to tensioned position so as prevent the possibilty if damage from a very slack chain. If when you are turning the engine by hand and the tensioner is retreating then there is a problem with the small circular ratchet at the base.
Yours looks a bit worn but I would say that it is a symptom and not a cause. The cause being that it is at it's limit due to a very stretched chain. The miles don't seen to have a big bearing on wear as I have seen them go 200000k and some like yours 60000, don't ask because I can't give an explanation as I would expect them to last better than 60000k. BMW do say to replace them at 60000 so they must expect that they will wear by then so as to warrant replacement.
I would be replacing it along with the tensioner, rails and guides.

do you have a pic from the other side brikee ....the crankcase side ..

just want to see if yours differs in some way

cheers

Here's the pic charlie99

Well, I think that answers the question I had, I'll replace chain, tensioner, guides and rails.
And it's off to the Bins I go!
Thanks again
Brickee

On V-Rods you can unscrew the entire tensioner from the side of the cylinder head. HD has a cool tool you can insert into the threaded tensioner hole to measure cam chain slack. A shaft sticks out with markings on it kind of like a giant turkey timer. Depending on how much slack is measured you remove the tensioner piston and add shims to it inside. It's pretty cool. You might hear a couple of knocks on start up and you know it's time to measure the slack in the cam chain.

thanks mate ...

yep looks exactly the same

let us know what the tensioner costs eh ? and what type you end up with ?

I'll ante in.......I'll guess you have a defect in an ignition coil.
If so.....the upgraded coils have orange towers where the ignition leads plug in.
Maybe right, maybe wong

true indeed ibj ...

we have seen tons of faulty ignition coils in those wet climates ....i even purchased some ...off a working bike in uk .....both open circuit secondarys .....just my luck

but in essence ...yes check the leads and coils brickee

primarys should measure 2.4 ohms

secondarys should measure 10.2 k round about

dont forget high tension leads can become intermittent ...whilst measuring them ...use aligator clips leads to make the connection ...then wiggle whislt measuring (you might have to find a good mating probe to get to the spark plug tops properly )

i might add check the breather plenum to crankcase

we're just guessing at this point

charlie99 , I ordered one from the Bins(exact replacement) for $52 USD plus the timing chain kit for $84 plus the shipping, I should see it in 10-14 days based on previous orders.
ibj, Gawd, I hope your guess is wrong after plunking down $136.00 plus shipping! Good point though, I'll check the resistances this afternoon on the coils.
The plug leads were new last winter and the plenum to crankcase hose looks good.
I'll just have to wait to put it back together to see what's what. In the mean time I've got splines and a clutch to lube, new tires to put on and a front master cylinder to replace. I think the time will pass quickly enough.
Cheers mates.

I will encourage you to investigate further the extensive posts about the engine output shaft (noise) BEFORE reinstalling the clutch.
The lack of further emotional energy prevented me from going further in while I was at that stage and I REGRET it now, because it's all back together and I have a very noisy set up when the bike is cold.
You on the other hand have the timing chain already apart and the clutch apart so you are already 3/4 of the way into correcting the shaft defect.
There is a bulletin somewhere but I currently can not find a way to upload the .pdf file to this post.
It is BMW #11 037 88 (2289).....I'm hopeful that another member will find it for you.
If your rivets are good (as many are) you will want to do the bulletin recommended upgrade to the spring & pin + shim.
The other thing I regret was that as long as I had all the stuff off, why I didn't pull the front 2 mounting bolts off the frame, remove the steering head and lift the frame off the top of the motor so I could repaint the whole frame correctly.

Hi ibj, some good points. I've read those posts re output shaft noise and when I replaced the clutch last winter I made a point of checking the output shaft rivets when I had the crankshaft cover off. From that limited point of view, they looked OK. But seeing as I've got that cover loose to do the timing chain, it will bear looking at again. I don't recall hearing any unusual noises coming from that area. I did replace the alternator output bearing last winter when I replaced the clutch.
The previous winter, I did pull the frame, did a good clean down and sprayed it with Rustoleum.
I'm not familiar with the bulletin regarding spring, pin and shim. What part of the engine are they associated with?
At this point, I'm going to replace all the timing gear components and see if that solves the problem. I'm kind of a plodder, I like to replace the most likely culprit(something that is definitely wrong), see if it solves the problem and go down the line. To me, shotgunning a problem, is an expensive way to solve a problem and doesn't enhance troubleshooting skills. It being an intermittent problem, makes it harder to diagnose and solve. I had enough experience working on intermittents with elevators to know it takes time and patience to finally solve the problem.
Anyway, I appreciate all the input you guys have given and sooner or later, this problem too will bite the dust and be part of the K archives.
I'll keep ya'll up to date with what I find.
Cheers

The output shaft had two separate issues. One was the rivets.
The shaft gear itself is a multi piece unit there is the big main gear sandwiched together with a wafer thin identical diameter gear. The thin gear is intended to have a spring loaded interference fit with the main gear, it can move around the center shaft independently from the main gear.
There is a circular spring ring between the 2 gears attached on one end to the main gear and on the other end to the free gear. When off the engine, the free gears teeth will be partially offset from those of the main gear.
When installing the shaft assy. one must "spring" both sets of gear teeth into identical alignment and clamp them that way against spring tension before meshing the output shaft (driven) gearing in against the matching crankshaft drive gear.
Once installed and secured in the engine, the clamp is removed allowing the spring pressure of the wafer gear on the output shaft......to fully absorb the clearance between the teeth of the 2 main gears. This in effect creates 0 lash between the gears and pre loads the teeth against each other hence eliminating the rattling sound that I think you are experiencing. It can sound remarkably like it's coming from the front of the motor.
The actual failure of the gear set is caused by a faulty design of the spring ring and it's retaining pin complemented by a wave style thrust washer between the wafer gear and the rear bearing.
After replacing the gear, spring & pin the wave thrust washer is replaced by a selective thrust washer and the output bearing is reinstalled.
Anyway, I hope you are right about the timing chain noise, but I'm guessing you'll only see marginal improvement if any.
Time will tell and I applaud your gallant efforts. One thing about having an old bike is for sure you'll always have some kind of list of things to attend to as soon as time permits.
As a side........the parts bike I just took apart had 235,000 on the original engine. The output shaft removed had NO spring pressure on the wafer gear. I hope to do the bulletin on that gear and switch it into my engine.

You can delete the spring loaded half of the gear. It is designed to reduce backlash at idle, but really isn't necessary. Deleting it completely eliminates the K bike whine. It's spooky how quiet the engine is without that infamous whine. I have ridden several bikes with this mod and such an engine is in the process of being built for a Frankenbike project of mine.

So , deleting the spring loaded gear that is designed to reduce backlash at idle takes the characteristic "whine" (that so many of us K riders have grown to love and admire) away. I fail to view that as an improvement.
Conversely, now that the "Idle backlash arresting parts" have been eliminated, could we expect that backlash to be increased and even noisier at (cold) idle?
What would be the benefit in making that horrible cold clackety rattle noise at idle, more prevalent, in order to quiet the whine?
The BMW bulletin appears to be intended to address a very real issue of Rattle. It does include a precaution to help reduce the risk of excessive whine noise by assuring that the exact gear teeth remain meshed in the same order that they were originally installed.

hmm it kinda reminds me of that "ducati rattle" on all those dry clutch 916 models ....doesnt take em long to get that characteristic rattle up (im guessing main to clutch drive gears as well as the clutch system )...dont hear it above 2k an in gear and under drive any how .