Author Topic: Riding fine, then bike died  (Read 4938 times)

Offline The Mighty Gryphon

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Re: Riding fine, then bike died
« Reply #50 on: August 17, 2023, 12:21:41 PM »
As I found on my bikes with LED idiot lights, a good rainstorm will turn on the oil light.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline frankenduck

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Re: Riding fine, then bike died
« Reply #51 on: August 17, 2023, 01:25:38 PM »
As I found on my bikes with LED idiot lights, a good rainstorm will turn on the oil light.

All of my Ks have had LEDs. Only on ONE out of 20 or so of them did I have that occur and it only glowed very dimly in really soggy weather.
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #52 on: August 17, 2023, 01:29:37 PM »
Well, I suppose the first step here is going to be draining the oil anyway. I'll inspect for any metal shavings/glitter with a magnet. After that, time to pop off the valve cover and the oil pump cover. Let's hope the oil is nice and clean with NO shavings!
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #53 on: August 17, 2023, 02:03:04 PM »
Well, I suppose the first step here is going to be draining the oil anyway.
Before that, tell us what the oil level is in the sight glass. After that, take off the oil filter cover and check if the oil filter is loose. After that, remove the oil filter and determine whether the filter has been installed with two gaskets instead of just one—one gasket on the oil filter itself and one left stuck to the engine's filter mounting flange after the removal of the previous filter. That eventually could cause pressure problems from the filter's loosening. After that, go metal detecting.  :laughing4-giggles:
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  • 1995 K75 89,000 miles

Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #54 on: August 17, 2023, 02:14:11 PM »
Hah! Sounds good. Oil level is halfway up the sight glass cold, I just changed that and the filter two weeks ago. No double gaskets on the oil filter, confirmed
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #55 on: August 17, 2023, 02:43:14 PM »
Did you locate the source of the noise with your screwdroscope?
  • Along the Ridley in Vermont.
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #56 on: August 17, 2023, 02:49:48 PM »
The squealing noise has disappeared for now, and I'm not quite sure why or how. I was able to get in position with my highly-advanced noise-finding screwdroscope and find something knocking at me from the crank case side of the engine, however.
  • Bordentown NJ
  • 1988 K75S

Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #57 on: August 17, 2023, 04:52:26 PM »
I strongly agree with Gryph here, I would not crank or start the bike again, since the oil pressure light remains on.

Not sure what you mean by the engine knocked out. I think you're saying suddenly there was no power from the engine but the engine was still running, and that the oil pressure light came on. This could mean that the output shaft rivets have failed. Then the crankshaft would turn, but the engine output shaft wouldn't if it's in gear.

Yeah, that's definitely a good idea. It doesn't sound like it's getting any better  :laughing4-giggles: It's not that there was no power, it's that there was a loss of power. It was basically like I wasn't getting the full range of power the bike had to offer. Not that it's much to begin with, but it seemed to be struggling.

I'm not sure what you mean by knocked out either. I mean there's literally a knock in my engine
  • Bordentown NJ
  • 1988 K75S

Offline daveson

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Re: Riding fine, then bike died
« Reply #58 on: August 17, 2023, 05:22:37 PM »
I deleted my previous post when I realised your brick is a k75 and I said to meyself "hey dumkopf, it's a K75 so it doesn't have output shaft rivets"

In post 37 when you said you got a squeal and knock, out of the engine, I was hearing that you got a squeal and knock out, of the engine. My mistake.
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline Laitch

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Re: Riding fine, then bike died
« Reply #59 on: August 17, 2023, 08:37:33 PM »
The squealing noise has disappeared for now, and I'm not quite sure why or how. I was able to get in position with my highly-advanced noise-finding screwdroscope and find something knocking at me from the crank case side of the engine, however.
You'll need to download the K100/K75 2V manual from this site. Having a copy of both Chiltons and Haynes can also help to clarify procedures. Haynes is a free downloadable at a few online sites. You'll need to get a tube of gasket-forming silicone. I use Permatex Black RTV but everyone with experience seems to have a favorite. You'll eventually be removing covers—crankcase, timing chain, Hall sensor, camshaft—to track what might be wrong. When replacing a cover, there must be absolutely no oil on the mating surfaces of the cover and engine. The gasket silicone must cure according to instructions—no shortcuts.

My first check would be of all the spark plug connections. The spark plugs should have terminal nuts on them and fit tightly on the wires. The secondary (thick) wire connections at the coils should be free of oxidation on both male and female terminals. The connections should be tight. The primary (thin) wire connection to each coil should unoxidized and tight. The battery terminal connections should be immovably tight. The battery ground strap connection should be clean, unoxidized and immovably tight. After all that has been truly verified—not just verified via fond recollection—the Hall sensor plate should be checked to verify that it hasn't loosened to skew the timing. These are the simplest places to go first as far as I'm concerned.


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  • 1995 K75 89,000 miles

Offline daveson

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Re: Riding fine, then bike died
« Reply #60 on: August 18, 2023, 07:15:11 PM »
Also, an important symptom I just remembered and left out (only because I'd never seen the light before and the icon had worn off). The oil pressure light was turning on while I was riding, which is when I promptly returned home.

If the light has never been on before, I'm thinking this could be the temperature light, and if the oil light icon has worn off, I spose the others are too (maybe the alt. light)

Are you sure it's the oil light that came on?

Just double checking.
  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #61 on: August 19, 2023, 06:55:19 AM »
If the light has never been on before, I'm thinking this could be the temperature light, and if the oil light icon has worn off, I spose the others are too (maybe the alt. light)

Are you sure it's the oil light that came on?

Just double checking.

All good - definitely the oil light. Cross referenced w/ pics of other instrument lights
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #62 on: August 19, 2023, 01:51:07 PM »
There are a few things that can trigger the oil light. Among them, the most common is a clogged or defective oil pressure switch. Replacing or cleaning that is uncomplicated. Another is a clogged oil pickup tube screen. The oil pan needs to be removed to examine that.
Get a move on with the simple stuff as outlined. If worse comes to worst, a lot of the more complicated stuff usually can be done with the engine still in the frame.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline frankenduck

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Re: Riding fine, then bike died
« Reply #63 on: August 19, 2023, 06:30:01 PM »
If the insulation on the oil switch wire wears and grounds inadvertently then that can also cause the oil light to come on.
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #64 on: August 31, 2023, 02:40:52 PM »
Alright guys, the work is starting this weekend. I've had no time to even check a simple thing. I drained the oil today because I'll need to do it anyway, and luckily no glitter or metal shavings have come out (and I'm guessing that's a good sign).

I'm going to be going through the list of things here one at a time. With no metal shavings, can I assume that means there's nothing catastrophic damaging the engine yet? I won't be riding it any time soon, I'm just curious.
  • Bordentown NJ
  • 1988 K75S

Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #65 on: August 31, 2023, 04:06:38 PM »
My first check would be of all the spark plug connections. The spark plugs should have terminal nuts on them and fit tightly on the wires. The secondary (thick) wire connections at the coils should be free of oxidation on both male and female terminals. The connections should be tight. The primary (thin) wire connection to each coil should unoxidized and tight. The battery terminal connections should be immovably tight. The battery ground strap connection should be clean, unoxidized and immovably tight. After all that has been truly verified—not just verified via fond recollection—the Hall sensor plate should be checked to verify that it hasn't loosened to skew the timing. These are the simplest places to go first as far as I'm concerned.

Hey Laitch, I just checked all of these out. All connections are good - terminal caps are on the spark plugs, both connections to all ignition coils are good. I used a wire brush on the flat connector tab under the coil to the right for good measure.

- Spark plugs are tight and clean
- Battery leads are tight
- Coil connections, primary and secondary, are tight and clean (M&F)
- Battery ground strap is clean and tight

I have no idea where the Hall Effect sensor plate is - I can't seem to find it in my Clymer or really anywhere. Do you have a nifty pic or a nice description to where I can find it?
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #66 on: August 31, 2023, 05:12:22 PM »
I have no idea where the Hall Effect sensor plate is - I can't seem to find it in my Clymer or really anywhere. Do you have a nifty pic or a nice description to where I can find it?
The Hall sensor assembly is behind a cover at the front of the engine. Below are listed a few sources for some illustrations; however, maybe you shouldn't get involved with that yet.

Let's take a deep breath.

Does the engine start and idle? Does the oil light shut off when it starts and idles? At ≥1200 rpm does the oil light flicker after it starts and idles?
In my electronic version of Clymer:
Hall effect sensor cover—Fig. 147, p. 68
Hall effect sensor— Fig. 144, p.69
Hall effect sensor cover—inside view, Fig. 145, p 70
Hall effect sensor cover—Figure 9, item #2, p. 89

In the BMW workshop manual downloadable from Motobrick:
Section 11–Engines, page 11-39
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #67 on: August 31, 2023, 07:44:30 PM »
Before I drained the oil, I would start the bike up and the oil light would be on a few seconds after it would start up.

Bike did start and idle, but it wouldn't start every time - kind of like it wasn't getting enough power to start. Then on my next attempt crank, it would start right up (with the knock and squeal). Battery was fully charged and terminals were tight
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #68 on: September 01, 2023, 11:25:46 AM »
You should check the function of the oil pressure switch. With the ignition switch turned to On, what happens with the light when you remove the connector from the switch and not let it touch the block? What happens with the light when you remove the connector from the switch and ground it to the block?
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #69 on: September 01, 2023, 02:07:45 PM »
Hey Laitch, I'll do that today for sure.

I actually know where the oil switch is! That'll be next on the list. I did pull the cover to the oil pump since I was curious and wanted to change the coolant anyway, and found this gunk on the impeller. It doesn't seem to come off easily, also the shaft won't move. Removing the oil pressure switch is next.

Will keep you updated!
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #70 on: September 01, 2023, 02:13:55 PM »
I actually know where the oil switch is! That'll be next on the list.
Good work! A seizing pump will lower oil pressure and is likely to make some compelling noises as it fails. You'll need to disassemble the pump completely to inspect its shaft and should replace its seals and, likely, its impeller. Post some photos of the parts.
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #71 on: September 01, 2023, 02:17:02 PM »
Definitely will! Should the impeller spin freely while the pump is attached to the bike?
  • Bordentown NJ
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Offline Laitch

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Re: Riding fine, then bike died
« Reply #72 on: September 01, 2023, 02:23:29 PM »
No.
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Offline rocketbrick

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Re: Riding fine, then bike died
« Reply #73 on: September 01, 2023, 03:49:13 PM »
Here’s the oil pressure switch connector. Looks suspicious, as it has a female connector in the cable sleeve, but a round connector on the switch.

Looks clean to me, but I have no idea how this thing was mounted
  • Bordentown NJ
  • 1988 K75S

Offline Laitch

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Re: Riding fine, then bike died
« Reply #74 on: September 01, 2023, 04:45:21 PM »
A spade connector on the end of the wire slips sideways onto the disc terminal of the oil pressure switch. Take another look and post another photo, but the root of your problem is likely to be the pump and you need to get various instructional resources and tools together to start disassembling it.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles