Author Topic: K75S - Clattering sound when clutch is out  (Read 5856 times)

Offline Quiltzig

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K75S - Clattering sound when clutch is out
« on: November 14, 2018, 08:46:52 PM »
I have just completed a cafe racer build and the new bike goes really well but has a rattling, clattering sound when the motor is running with the clutch disengaged. As soon as you pull in the clutch it goes away. I do not recall it sounding like this when I bought it (that was 3 years ago and it has not been run up at all in that time), and my other K Bikes have never had this rattle. Any ideas?
  • Hamilton - New Zealand
  • K75S
1987 K75S - cafe racer project
2016 R9T (wifes ride)
2004 K1200RS

Offline johnny

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Re: K75S - Clattering sound when clutch is out
« Reply #1 on: November 14, 2018, 10:01:55 PM »
greetings...

lets hear it... post up a video with sound...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Quiltzig

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Re: K75S - Clattering sound when clutch is out
« Reply #2 on: November 14, 2018, 11:41:12 PM »
will  have to do this when I can start her up again... coming home today I got brake fluid spraying over the tank from the front Master cylinder, so now I have to get all that off to see what is going on. Possibly the oring seal underneath the plastic tank, as fluid appears to be coming from the join between the metal and plastic sections. I am now wondering how I get the throttle cable off in order to slide the MC off the bar. Nothing in the Haynes manual about that!
 
  • Hamilton - New Zealand
  • K75S
1987 K75S - cafe racer project
2016 R9T (wifes ride)
2004 K1200RS

Offline TX brick

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Re: K75S - Clattering sound when clutch is out
« Reply #3 on: November 15, 2018, 06:52:23 AM »
If bike is in neutral with clutch lever out, then you are hearing the gears in the front of the transmission turning. Unless it is real loud-normal. Most manual transmissions including cars do this.
Ron

91 K75RT

Belton Tx

Offline johnny

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Re: K75S - Clattering sound when clutch is out
« Reply #4 on: November 15, 2018, 07:45:03 AM »
greetings...

does it sound like a miss...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline The Mighty Gryphon

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Re: K75S - Clattering sound when clutch is out
« Reply #5 on: November 15, 2018, 08:29:40 AM »
Does it sound like a Mrs.?
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Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #6 on: November 15, 2018, 08:58:32 AM »
More than likely it's a Ms. but I think we're stitching with the wrong thread.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
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Offline johnny

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Re: K75S - Clattering sound when clutch is out
« Reply #7 on: November 15, 2018, 09:01:01 AM »
greetings...

i wanna listen to a purple caferacer...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #8 on: November 15, 2018, 10:56:54 AM »
I am now wondering how I get the throttle cable off in order to slide the MC off the bar. Nothing in the Haynes manual about that!
You don't need to remove the cable; you just need to disconnect it. Download the manual at the link in this post on the site. Go to Chapter 32, pp. 11–12 (32–11.0) for complete instruction. After that, follow the Haynes instructions or BMW's.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Chaos

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Re: K75S - Clattering sound when clutch is out
« Reply #9 on: November 15, 2018, 11:10:50 AM »
clattering sound when the motor is running with the clutch disengaged. As soon as you pull in the clutch it goes away

I'm thinking you mean noisy when the clutch is engaged?  Check oil in tranny? (sorry, too obvious but you never know......)
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
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Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #10 on: November 15, 2018, 11:25:36 AM »
I'm thinking you mean noisy when the clutch is engaged?  Check oil in tranny? (sorry, too obvious but you never know......)
From what I've observed around here, there is no Brick condition that is too obvious. Simple causes are often neglected during  lengthy speculations, presumptions and recommendations surrounding diagnosis of perceived maladies.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #11 on: November 15, 2018, 11:52:05 AM »
. . . the new bike goes really well but has a rattling, clattering sound when the motor is running with the clutch disengaged. As soon as you pull in the clutch it goes away.. . . and my other K Bikes have never had this rattle. Any ideas?
Here is some of the epic K75 Rattle Thread. What its conclusion amounts to for me is don't idle with the clutch engaged unless you're noise tolerant or deaf. :giggles That works.  :2thumbup:
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Chaos

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Re: K75S - Clattering sound when clutch is out
« Reply #12 on: November 15, 2018, 11:59:47 AM »
From what I've observed around here, there is no Brick condition that is too obvious.

very true but I'm trying to avoid the OP posting a litany of his qualifications as a mechanical guru and overlooking such an obvious step insults his genealogy to the extent he shall never darken our cyber sphere again.
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #13 on: November 15, 2018, 01:23:36 PM »
very true but I'm trying to avoid the OP posting a litany of his qualifications as a mechanical guru and overlooking such an obvious step insults his genealogy to the extent he shall never darken our cyber sphere again.
You're a veritable monument of empathy.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Quiltzig

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Re: K75S - Clattering sound when clutch is out
« Reply #14 on: November 15, 2018, 05:10:05 PM »
Guys - the clattering rattle is when the bike is idling with the clutch disengaged. So it is in neutral, not in gear, and the clutch lever is not pulled in, so the clutch is disengaged.
The rattle sounds like really loose tappets - when I have the brake MC back on the bike and the throttle cable connected again I will post a short video clip for clarity. Thanks for all the responses, and your humour!
  • Hamilton - New Zealand
  • K75S
1987 K75S - cafe racer project
2016 R9T (wifes ride)
2004 K1200RS

Offline Laitch

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Re: K75S - Clattering sound when clutch is out
« Reply #15 on: November 15, 2018, 10:24:57 PM »
Guys - the clattering rattle is when the bike is idling with the clutch disengaged. So it is in neutral, not in gear, and the clutch lever is not pulled in, so the clutch is disengaged.
Actually, the clutch is engaged when the handlebar clutch lever is not pulled in. Its friction disc is engaged with the rotating clutch housing via the pressure plate and transferring that rotation to the transmission's input shaft while the transmission is in neutral. Gear shifting will be difficult or impossible until you pull the handlebar lever in to disengage the clutch friction disc from the housing and thereby cause the housing to cease rotating the input shaft so you can shift into gear. That is why a diet rich in spinach aids quiet idling.

The clutch lever is released, the clutch disc engages with the housing, the housing rotation transfers engine power by means of the friction disc hub's connection to the transmission input shaft, the transmission transfers power through its gears into its output shaft which is connected to the driveshaft, the driveshaft transmits power into the rear drive input shaft, the rear drive converts the power into wheel rotation which results in your moving forward until you dump the moto because you were distracted by the impending choice between having pork tenderloin or tofu scrambled with cumin, peppers and baby kale for lunch and were leaning toward the tenderloin.

Regardless, without hearing the noise, who can be certain of its source? Even when it is heard, certainty is elusive. Odds are large that the noise will haunt you until you accept it—like I've done with the aid of ear plugs, a well-developed lever grip and a determined state of denial—or fix it.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline ^Adrninistrator

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Re: K75S - Clattering sound when clutch is out
« Reply #16 on: November 16, 2018, 04:55:34 AM »
This thread is locked until OP posts audio.
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