Post by: bmwcyclist on March 08, 2020, 01:13:29 PM
Symptoms: Idle fine. Rev in neutral fine. I engage gear, release clutch and I get a vibration and noise that goes away in just a few seconds.
Other possibly relevant information
Clutch adjustment has been checked and rechecked.
Had a leak at clutch/gearbox boot, replaced boot.
Alternator and monkey nutz recently replaced.
I was wondering if the problem might be related to the clutch throw-out rod/bearing system but I did not have success finding a thread on that topic.
Thank you.
Post by: The Mighty Gryphon on March 08, 2020, 02:49:28 PM
DSCN1758.JPG (46.82 kB . 768x576 - viewed 582 times) I have torn my engine down to to fix it, and it appears to be intentional, and after nearly 70,000 miles there is no signs of any wear or damage. It sort of sucks that such a nice bike has that thing going on, but I have just chalked it up to being part of the charm of my bike.
Have you checked the valve clearances and balanced the throttle bodies? That will help to smooth out the running of the engine.
Post by: bmwcyclist on March 08, 2020, 03:53:36 PM
Because the noise only happens right after engagement of the clutch and for a few seconds after drive-away, I am making the assumption that it is not related to the alternator unless you think my thinking is misplaced.
Have you checked the valve clearances and balanced the throttle bodies?
Yes. Thank you for asking. Any other ideas?
Post by: Laitch on March 08, 2020, 04:31:35 PM
Because the noise only happens right after engagement of the clutch and for a few seconds after drive-away,Is this noise a knock, rattle, squeal, screech, rumble or howl? Is engagement of the clutch smooth or hesitant? Does this noise happen with every engagement of the clutch after every shift, or just in first gear from a stop?
Can you record the noise, post it on YouTube and send us a link to the recording?
Post by: bmwcyclist on March 08, 2020, 05:03:47 PM
Is this noise a.....rattle,
Yes
Is engagement of the clutch smooth or hesitant?
smooth
Does this noise happen with every engagement of the clutch after every shift, or just in first gear from a stop?
Just in first gear from a stop, or just checking I found also from second from a stop.
Can you record the noise, post it on YouTube and send us a link to the recording?
Yes, I will attempt to do so.
Thank you.
Post by: johnny on March 08, 2020, 05:09:08 PM
does it sound like this...
https://youtu.be/9HWAOj138Ew
j o
Post by: Laitch on March 08, 2020, 05:17:24 PM
Is this noise a . . . rattle . . .?I don't want to disappoint you and make this seem less serious than you might like it to be, but there is a chance that you aren't giving it enough throttle at takeoff and aren't running up to high enough revs before you shift to second gear. Bricks like revs. Maybe your other 75 is just different.Yes
Take heart though. It could be something serious after all. :laughing4-giggles: We're all eager for the recording.
Post by: Laitch on March 08, 2020, 05:44:54 PM
. . . just checking I found also from second from a stop.Takeoff from second gear needs high revs and careful clutch release. I wasn't recommending that as part of diagnosis.
Post by: Bon Jon Bovi on March 08, 2020, 07:57:21 PM
New bricker here so if that's total bollocks, apologies.
Post by: bmwcyclist on March 08, 2020, 08:14:00 PM
This one is after the bike warmed up and it had the vibration/noise BOTH in 1st and 2ond gear, only time I observed this.
https://youtu.be/kxt3oC62rkE
This one is initial start out cold. Case is blocking video but you can hear well.
TWO starts with the sound disappearing during roll out at 5 seconds and on the second run 18 seconds.
https://youtu.be/kxt3oC62rkE
Post by: Laitch on March 08, 2020, 08:28:17 PM
Ok, did some riding got some audio/video.Thanks for the video. More throttle from the get-go. That tach shouldn't be climbing then plunging. The rattle seems to be happening when acceleration is recovering. I call that lugging. You can call me hopeful.
How does your other Brick perform in first and second gear?
Post by: Laitch on March 08, 2020, 08:42:33 PM
. . . if that's total bollocks, apologies.We don't have bollocks in Vermont so I don't recognize it if it is. Is it like fajitas?
Post by: Filmcamera on March 08, 2020, 08:49:36 PM
Post by: The Mighty Gryphon on March 08, 2020, 08:53:16 PM
Question: Do you hear the noise at a specific engine speed? On my bike I get the clanking at 1500 rpm regardless of whether the bike is in gear, the clutch is in or out, or if it's moving or standing still.
I get the clank on my bike starting from a stop in first gear, but after that, the engine doesn't drop the rpm's enough when shifting to set it off.
Post by: johnny on March 08, 2020, 09:12:25 PM
the moar the motobricker wears earpluggs the moar they stop freaking and getts some yeeeehaaaa motobricking...
try it...
j o
Post by: Laitch on March 08, 2020, 09:50:36 PM
On my bike I get the clanking at 1500 rpm regardless of whether the bike is in gear, the clutch is in or out, or if it's moving or standing still.It isn't clanking on his. That might be Marley's ghost you're hearing. Does it happen more around Christmas?
Post by: The Mighty Gryphon on March 08, 2020, 10:17:05 PM
Post by: volador on March 09, 2020, 12:26:58 AM
Ok, did some riding got some audio/video.
This one is after the bike warmed up and it had the vibration/noise BOTH in 1st and 2ond gear, only time I observed this.
https://youtube/kxt3oC62rkE
This one is initial start out cold. Case is blocking video but you can hear well.
TWO starts with the sound disappearing during roll out at 5 seconds and on the second run 18 seconds.
https://youtube/kxt3oC62rkE
Yo, BC a total of 12 seconds of bullocks, bugger
Post by: bmwcyclist on March 09, 2020, 08:23:25 AM
Quality is not great but you can really hear when the rattle stops during roll out at 5 seconds and on the second run 18 seconds.
https://www.youtube.com/watch?v=NEcd1Qcmd7c
Post by: The Mighty Gryphon on March 09, 2020, 10:32:15 AM
Have you done a compression test to see how balanced all the cylinders are? Checked that all the valve clearances are correct and reasonably matched? A good throttle body balance and new spark plugs won't hurt. The throttle body balance is important to get all the cylinders working as close to the same as possible.
Like I said earlier, I consider that rattle just off idle to be part of the charm of my bike. 3M Skull Skrews ear plugs help a lot too.
Post by: bmwcyclist on March 09, 2020, 10:47:07 AM
I just listened with my headphones. Sounds like the balance shaft in my K75RT. My theory is that the slightest imbalance between the cylinders will cause that tang to rattle around in the slot. Once the engine speed gets to a certain point the shaft is spinning too fast to let things rattle enough to hear. There does seem to be a second, maybe resonant rattle at about 3000rpm on my bike. It's hardly noticeable because it's a lot quieter and doesn't really happen until the bike has a lot of miles and needs a tune up.
Have you done a compression test to see how balanced all the cylinders are? Checked that all the valve clearances are correct and reasonably matched? A good throttle body balance and new spark plugs won't hurt. The throttle body balance is important to get all the cylinders working as close to the same as possible.
Like I said earlier, I consider that rattle just off idle to be part of the charm of my bike. 3M Skull Skrews ear plugs help a lot too.
I did sync the throttle bodies BUT one was significantly out compared to the others. I did a spray test for air leaks and found nothing. I just ordered a set of new injectors, perhaps that will all them to be in closer adjustment and lead to smoother running. I checked the valves, they were good. I also replaced the Z-hose and renewed the vacuum caps.
.
Post by: bmwcyclist on March 09, 2020, 11:08:54 AM
I also have two close friends with K75RT bikes that I ride with (one has 2 1990 K75RTs and 1 has a 1991 K75RT) they also do not produce this sound/vibration.
Post by: Laitch on March 09, 2020, 12:00:02 PM
Note, I have a 1990 K75 (factory low) that does not produce this sound . . .Your last submission is the way to do a mobile sound recording! icon_cheers
I also have two close friends . . . they also do not produce this sound/vibration.
Have you inspected, cleaned and appropriately lubricated all driveline components all the way up to the intermediate housing?
While waiting for your new injectors to arrive, I suggest you perform a compression test with wide-open throttle on this neglected moto. Based on its results being good, and if you hadn't done so already, remove the throttle body air adjustment screws, clean them, clean their ports, replace their o-rings, reinstall them then redo the TB balance.
I don't hear much that concerns me. Your 1990 is barely broken-in so I am reluctant to use its noise level for comparison. In your last recording, your throttle input seems better. If you discover in your research something that achieves your goal of lowering the level of noise type that concerns you, please post it here. Other than that, I have only one fallback position.
Wear earplugs.
Post by: johnny on March 09, 2020, 01:16:50 PM
i thinks its the exhaust mount...
j o
Post by: bmwcyclist on March 09, 2020, 06:48:25 PM
I will check back in after:
Compression test
Injector install
Port clean and 0-ring replacement
Exhaust mount check
Thanks!
Post by: The Mighty Gryphon on March 09, 2020, 07:21:00 PM
I also had that problem with the slack in the cable allowing the arm to rattle on the muffler. Made a heck of a racket. Fix is real easy, take up about a mm of slack at the adjuster and readjust the bolt at the pushrod. Alternatively, you may be able to move the exhaust down a way from the arm a little.
Post by: bmwcyclist on March 09, 2020, 09:40:40 PM
if you hadn't done so already, remove the throttle body air adjustment screws, clean them, clean their ports, replace their o-rings, reinstall them then redo the TB balance.
I can’t seem to locate the part number or size of the o-rings on the throttle body adjustment ports (see attached)
Post by: The Mighty Gryphon on March 09, 2020, 09:56:41 PM
16 13 54 1 461 261 ADJUSTING SCREW 0.01 3 $10.87
ONLY IN CONJUNCTION WITH :
-- 13 11 1 257 819 GASKET RING 3 $3.00
It's not shown on the diagram, so it doesn't have a reference number. The fact that it's labeled as a choke shaft o-ring adds to the confusion.
Post by: bmwcyclist on March 09, 2020, 10:08:13 PM
Post by: The Mighty Gryphon on March 09, 2020, 10:12:40 PM
Post by: Laitch on March 09, 2020, 10:58:02 PM
I can’t seem to locate the part number or size of the o-rings on the throttle body adjustment ports (see attached)Terminology is the result of inaccurate German translation of English. Examples are common in the fiche. When you see the line ONLY IN CONJUNCTION WITH:, the part without a diagram reference number that follows that line relates to the part with a diagram number above that line.You're looking for the gasket ring.
16 13 54 1 461 261 ADJUSTING SCREW 0.01 3 $10.87
ONLY IN CONJUNCTION WITH :
-- 13 11 1 257 819 GASKET RING 3 $3.00
It's not shown on the diagram, so it doesn't have a reference number. The fact that it's labeled as a choke shaft o-ring adds to the confusion.
Post by: bmwcyclist on March 10, 2020, 12:31:00 PM
Post by: Laitch on March 10, 2020, 02:35:57 PM
. . . for peace of mind I ordered them from MAX.If it were only that simple. Oh yeah (http://www.motobrick.com/gallery/videos/1601_10_03_20_2_23_38.mp3). :laughing4-giggles:
Post by: volador on March 10, 2020, 04:13:32 PM
Thanks again, they are likely the same vtron O-rings I have in my garage but for peace of mind I ordered them from MAX.
If it were only that simple. Oh yeah (http://www.motobrick.com/gallery/videos/1601_10_03_20_2_23_38.mp3). :laughing4-giggles:
Oh yeah sing it Muddy!
Let us know if you get some M&Ms with your order?
Post by: Laitch on March 10, 2020, 05:05:39 PM
Oh yeah sing it Muddy!That's Lightnin' Hopkins.
Post by: bmwcyclist on March 15, 2020, 05:09:14 PM
Compression test = Done. Reasonable and similar for each cylinder
IMG_7198.jpg (45.17 kB . 768x576 - viewed 539 times) IMG_7197.jpg (62.37 kB . 768x576 - viewed 530 times)Injector install = New injectors, new o-rings, cleaned injector pipe, replaced injector balance rubber caps
Port clean and 0-ring replacement, cleaned and done.
Exhaust mount check = replaced stock mica gasket checked all mountings
When I went to balance the throttle bodies I still could not get them to balance. The rearmost cylinder needs to be backed all the way out and still does not balance to the center cylinder
https://youtu.be/fhJ8lzyVqx8
With the adjustment screws all the way in the front and center cylinders balance well.
https://youtu.be/iGF4UnBothI
A few weeks earlier I had sprayed the throttle bodies with carb cleaner and did not see a drop in RPM. I don't know if perhaps I was concentrating on the top of the bodies or not but this time I was out of carb cleaner so I grabbed the silicon spray next to me and the RPM drops hard when I spray the bottom of the throttle body of the front and middle cylinders.
No idea if this relates to my noise issues but obviously I will have to fix this first.
https://youtu.be/A7eyu30BFMI
Post by: Laitch on March 15, 2020, 05:23:26 PM
I grabbed the silicon spray next to me and the RPM drops hard when I spray the bottom of the throttle body of the front and middle cylinders. . . .I will have to fix this first.You've got leaks. You're on the right track. Check the z-hose crankcase breather, too. You will need to find all leaks and stop them, probably by replacement with new parts. After that, you'll likely be able to balance the throttle bodies. That will mean the engine will have more power at takeoff and likely rattle less.
Post by: bmwcyclist on March 15, 2020, 05:39:22 PM
You've got leaks. You're on the right track. Check the z-hose crankcase breather, too. You will need to find all leaks and stop them, probably by replacement with new parts. After that, you'll likely be able to balance the throttle bodies. That will mean the engine will have more power at takeoff and likely rattle less.
Do I need to use the single use clamps?
.
Post by: Laitch on March 15, 2020, 05:50:04 PM
Do I need to use the single use clamps?That's up to you. Read this thread (https://www.motobrick.com/index.php?topic=9652.0)—all of it. The width of the band is critical.
Post by: alabrew on March 17, 2020, 12:30:13 PM
Post by: billday on March 17, 2020, 03:51:34 PM
Post by: bmwcyclist on March 21, 2020, 02:54:15 PM
Sync'ed like a charm at idle and higher RPM.
I am not getting a consistent "click" with the TPS will need to read up on adjusting that now.
https://youtu.be/cYJtmly_5s0
Also what the heck is this??? Found it on my wiring harness when installing the airstack box.
Photo Mar 21, 10 32 09 AM.jpg (40.53 kB . 768x576 - viewed 463 times)
Post by: The Mighty Gryphon on March 21, 2020, 03:46:40 PM
Post by: The Mighty Gryphon on March 21, 2020, 04:01:02 PM
As to the clicky thing, connect an ohmmeter between pins #9 and #3 on the big Jetronic connector under the seat. When the throttle is closed you should have 0 ohms, and when the throttle is cracked the resistance should go to infinity.
Post by: Laitch on March 21, 2020, 04:27:49 PM
Also what the heck is this??? Found it on my wiring harness when installing the airstack box.This is what fits into it to optimize the mixture at high altitude ≥6000ft. It's called a contact ring by BMW. 61131459504 The system's worth has been given mixed reviews.
Post by: bmwcyclist on March 21, 2020, 06:09:20 PM
The ohm meter was MUCH better than listening for the clicks.
All back together.
Rider too tired to test ride today, will see about tomorrow.
BTW, I did notice when setting the idle that I was getting intermitten noise from the area of the alternator. That is a bummer as I replaced the bearing in the bell housing in the fall and bought a brand new alternator, monkey nutz and cup-connector thingie.
Post by: Laitch on March 21, 2020, 06:24:30 PM
Post by: bmwcyclist on March 21, 2020, 06:28:18 PM
Anytime a thingie is installed instead of a part, trouble is likely to follow. :laughing4-giggles:
It's not like I used a whatchamacallit.
Post by: Laitch on March 21, 2020, 06:30:42 PM
It's not like I used a whatchamacallit.The outcome could be better with one of those. Points are given for a high syllable count.
Post by: The Mighty Gryphon on March 21, 2020, 06:45:56 PM
That noise could very well be the clanking/tapping of the balance shaft. If it is intermittent and around the idle rpm, I would just ignore it. As I think I said earlier, it's part of the bike's charm and, as far as I can tell, doesn't hurt anything.
And the blue glove. Hang onto it. They are getting damn near as valuable as toilet paper. I have brought mine in from the garage and have them well hidden. Last Thursday a clerk at Harbor Freight told me she had to break up an argument over a box of those gloves.
Like they say, "from my cold dead hands".
Post by: bmwcyclist on March 22, 2020, 05:23:18 PM
The TB work made a huge difference in responsiveness and overall performance.
Unfortunately, it made no change in the vibration and sound issue other than now the engine is quieter to it made the errant sound more clear.
You can hear the sound QUIT between 2 and 3 seconds into the video.
https://youtu.be/cQPzJptxqcA
Post by: Laitch on March 22, 2020, 05:46:09 PM
Now it sounds to me like vibration acting on a body panel or panel fitting. Are the airbox clips tight? Is the air snorkel loose. Is there movement of any fairing. Is a radiator cover grill loose?
Post by: bmwcyclist on March 22, 2020, 07:11:28 PM
Good recording!
Now it sounds to me like vibration acting on a body panel or panel fitting. Are the airbox clips tight? Is the air snorkel loose. Is there movement of any fairing. Is a radiator cover grill loose?
Thanks!
Airbox clips are in place in tight, I put in a new air filter during the TB work and also removed and reinstalled the air snorkel and front bottom of the faring.
The vibration is enough that I feel it and there is no significant wind/airflow to move a body panel.
Post by: Laitch on March 22, 2020, 07:24:19 PM
The vibration is enough that I feel it and there is no significant wind/airflow to move a body panel.I'm not referring to airflow; I'm referring to the sympathetic vibration of a part or fitting.
Post by: bmwcyclist on March 22, 2020, 07:31:23 PM
I'm not referring to airflow; I'm referring to the sympathetic vibration of a part or fitting.
I thought so, just covering the bases.
Post by: The Mighty Gryphon on March 22, 2020, 07:40:24 PM
My K75RT does a very similar thing. The noise starts just above idle, somewhere between 1200-1300rpm and goes until the rpm gets to about 2000-2200. Then it suddenly stops as yours does.
The only difference with your noise is that it doesn't have quite the metallic clank to it that mine has, otherwise it's exactly the same.
Post by: bmwcyclist on March 22, 2020, 10:27:26 PM
At what rpm does the noise stop?
My K75RT does a very similar thing. The noise starts just above idle, somewhere between 1200-1300rpm and goes until the rpm gets to about 2000-2200. Then it suddenly stops as yours does.
The only difference with your noise is that it doesn't have quite the metallic clank to it that mine has, otherwise it's exactly the same.
interesting. I will check.
Post by: bmwcyclist on April 05, 2020, 12:09:50 AM
As previously stated the sound / vibration seemed to be on the alternator side.
I spent some time with a mechanics stethoscope and the sound seem to be coming from the bell housing area.
I ordered a new alternator from enduralast, it arrived yesterday.
I pulled the alternator. I could find no play, although there seemed to be an almost imperceptible rough spot, the ne alternator did not have one.
I checked the alternator dog and found some slight play.
The monkey nuts were ok, but oddly worn considering I replaced them only a few months ago.
I removed the bolt holding the alternator dog and found it was only hand tight.
I put a lock washer under the bolt and reinstalled the dog. Now it has no play.
I installed the new alternator with a new set of monkey nuts.
Noise and vibration were gone, noticeable change in sound.
Went for a 5 mile test run, so far no return of noise.
.
Post by: volador on April 05, 2020, 12:33:47 AM
I believe I have found the problem.
As previously stated the sound / vibration seemed to be on the alternator side.
I spent some time with a mechanics stethoscope and the sound seem to be coming from the bell housing area.
I ordered a new alternator from enduralast, it arrived yesterday.
I pulled the alternator. I could find no play, although there seemed to be an almost imperceptible rough spot, the ne alternator did not have one.
I checked the alternator dog and found some slight play.
The monkey nuts were ok, but oddly worn considering I replaced them only a few months ago.
I removed the bolt holding the alternator dog and found it was only hand tight.
I put a lock washer under the bolt and reinstalled the dog. Now it has no play.
I installed the new alternator with a new set of monkey nuts.
Noise and vibration were gone, noticeable change in sound.
Went for a 5 mile test run, so far no return of noise.
Great job! You've quickly become the resident alternator expert. Stay safe
Post by: milq on April 05, 2020, 02:00:00 AM