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Author Topic: New guy here  (Read 7450 times)

Offline Zfoster8

  • Motobrick Curious
  • Posts: 29
New guy here
« on: October 31, 2019, 11:03:37 AM »
Good morning everyone, thanks for having me!

I just picked up an '87 K75S about two weeks ago. Hell of a deal, but it needs some work and some TLC. I have a feeling i will be lurking and posting a lot about this bike in the near future.

Picked the bike up "not running" but I can bump start it (running start and let the clutch out) and it rides and runs beautifully. Previous owner apparently was an aspiring electrician and there are some pretty questionable wiring modifications that need to be sorted out, but it's pretty at least.

By the way, the stupid stubby exhaust is already gone, put the stock muffler back on. Runs and sounds much better.

Previous bikes have included 2016 BMW GS650, 1981 CB900F, and currently also own a beautiful running and riding 1975 Elsinore MT250.


* K75S_1.jpg (92.39 kB . 768x576 - viewed 509 times)
* K75S_2.jpg (102.18 kB . 768x576 - viewed 422 times)
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  • Eugene OR
  • Now: 1987 K75S Then: 1981 CB900F

Offline beemuker

  • ^ Quintessential Motobricker
  • Posts: 1110
Re: New guy here
« Reply #1 on: October 31, 2019, 11:13:29 AM »
congrats. nice looking brick, one of the best , but I may be biased.
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  • Panama City, FL
  • '00 R1100RT,’92 K75 RT,past tense:'83 R80ST, '93 K1100LT,,94 R1100RS K75s, Honda NC700, Suzuki Bandit 1200, bmw R75/5 Honda 750

Offline Laitch

  • Faster than a speeding pullet
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Re: New guy here
« Reply #2 on: October 31, 2019, 11:17:13 AM »
Welcome! Thanks for posting the photos. How many miles are on this specimen's odometer?
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  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Online Chaos

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  • Mars needs women!
Re: New guy here
« Reply #3 on: October 31, 2019, 11:18:35 AM »
Welcome, good looking survivor, takes me back to when my bike was new!  Lots of help available here to get it sorted out, it's a keeper.
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  • 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 Zfoster8

  • Motobrick Curious
  • Posts: 29
Re: New guy here
« Reply #4 on: October 31, 2019, 11:37:24 AM »
Laitch,

Odometer is just a hair over 31,000 miles. Still a baby!
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  • Eugene OR
  • Now: 1987 K75S Then: 1981 CB900F

Online Chaos

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Re: New guy here
« Reply #5 on: October 31, 2019, 12:24:35 PM »
The speedo pods on early K75's were notorious for malfunctioning, I'd take that reading with a grain of salt. 
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  • 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 Zfoster8

  • Motobrick Curious
  • Posts: 29
Re: New guy here
« Reply #6 on: October 31, 2019, 12:31:42 PM »
That is a good thing to keep in mind, i wonder if there is a good way to see if it has been replaced or not.

The odometer seems to be working well right now though, so that's a plus.
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  • Eugene OR
  • Now: 1987 K75S Then: 1981 CB900F

Online Chaos

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Re: New guy here
« Reply #7 on: October 31, 2019, 12:59:18 PM »
somewhere over on BMWMOA there was a post of determining mileage by wear on the little pyramids on the brake pedal.  I checked it against mine and it was pretty accurate, but I no longer have access to that site.  Maybe someone else can research it.
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  • 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 beemuker

  • ^ Quintessential Motobricker
  • Posts: 1110
Re: New guy here
« Reply #8 on: October 31, 2019, 01:09:11 PM »
Quote from: Chaos on October 31, 2019, 12:59:18 PM
somewhere over on BMWMOA there was a post of determining mileage by wear on the little pyramids on the brake pedal.  I checked it against mine and it was pretty accurate, but I no longer have access to that site.  Maybe someone else can research it.
thanks for that, If I ever sell mine I'll touch 'em up.
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  • Panama City, FL
  • '00 R1100RT,’92 K75 RT,past tense:'83 R80ST, '93 K1100LT,,94 R1100RS K75s, Honda NC700, Suzuki Bandit 1200, bmw R75/5 Honda 750

Offline stokester

  • ^ SuperNatural Motobricker
  • Posts: 805
Re: New guy here
« Reply #9 on: October 31, 2019, 03:57:19 PM »
Very nice bike! Welcome.

Lots of great info on this site and helpful forum members.
Go ahead and update your profile with bike info and general location.
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  • Yorktown Virginia
  • '94 K75S Dakar Yellow - '93 K75S Seiden Blau - '91 R100RT Bermuda Blue- '78 R100S Smoke Red

Offline daveson

  • ^ Quintessential Motobricker
  • Posts: 1043
Re: New guy here
« Reply #10 on: October 31, 2019, 04:44:31 PM »
Hi

I've got five bricks and none of them look that neat. The front brake discs have been replaced so I'll say it's done many more miles,  but it doesn't matter,  they can easily clock up 400,000 just like a car. l also think of brake pedal wear as a hallmark of genuine mileage.

The speedo was possibly repaired rather than replaced. You might see if the screws were turned with a screw driver. Maybe post photos of the cluster and pedal and stuff. Since you just got it,  now would be the best time to thank the previous owner for selling it to you and find out as much about its history as you can.

More importantly it looks like it was not only cared for but loved by the previous owner. I wish mine was that colour.
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  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline Martin

  • ^ Quintessential Motobricker
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Re: New guy here
« Reply #11 on: October 31, 2019, 05:04:22 PM »
To confuse future buyers don't use the brakes. In emergencies just drag your feet.
Regards Martin.
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  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline daveson

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Re: New guy here
« Reply #12 on: October 31, 2019, 05:45:55 PM »
Eureka, that's why the front discs were replaced, I'll keep that in mind for the future.
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  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline Past-my-Prime

  • ^ SuperNatural Motobricker
  • Posts: 501
  • All of us are better when we're loved.
Re: New guy here
« Reply #13 on: October 31, 2019, 09:01:46 PM »
Lovely color - enjoy your bike - enjoy the club - hesitate to post questions! - check your splines. . . .
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  • North Shore of Lake Superior (in my garage)
  • BRICK: 1989 K75 RT - Rocinante; NON-BRICK: 2007 F650 GS Dakar - Betty Blue

Offline Zfoster8

  • Motobrick Curious
  • Posts: 29
Re: New guy here
« Reply #14 on: October 31, 2019, 09:05:14 PM »
Who uses back brakes anyway?

Been digging further into the bike and finding more bad wiring everywhere i look. Good thing its the end of riding season, i am ripping this whole bike apart!
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  • Eugene OR
  • Now: 1987 K75S Then: 1981 CB900F

Offline daveson

  • ^ Quintessential Motobricker
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Re: New guy here
« Reply #15 on: October 31, 2019, 09:34:56 PM »
I used to only use front brakes, but pushed myself into the habit of using both in case an emergency ever comes my way I'll be using both on auto pilot.
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  • Victoria, Australia
  • Current;'85 K100RT~100,000km; four other bricks. Past; 1500 Vulcan, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline stokester

  • ^ SuperNatural Motobricker
  • Posts: 805
Re: New guy here
« Reply #16 on: October 31, 2019, 10:33:13 PM »
Quote from: Zfoster8 on October 31, 2019, 09:05:14 PM
Who uses back brakes anyway?

Been digging further into the bike and finding more bad wiring everywhere i look. Good thing its the end of riding season, i am ripping this whole bike apart!
Eliminating any twist 'n tape, poor butt connectors and anything "posi" with proper connections and cleaning all connectors and ground connections will go a long way toward a reliable ride.  Be especially mindful of the 4-pin that comes from the tank to connect the fuel pump and fuel level sensor.

Many of us have found DeoxIT to be a superior contact cleaner.
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  • Yorktown Virginia
  • '94 K75S Dakar Yellow - '93 K75S Seiden Blau - '91 R100RT Bermuda Blue- '78 R100S Smoke Red

Offline Zfoster8

  • Motobrick Curious
  • Posts: 29
Re: New guy here
« Reply #17 on: October 31, 2019, 10:36:26 PM »
Excellent advice and definitely a great starting point! All of the lights are LED and it looks like a lot of the "custom" wiring was to accommodate the lighting upgrade. There is a whole set of fuse looking things under the seat that i am guessing are to make the blinkers blink the right speed with the stock relay. 

Electrical is not my strong point unfortunately.
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  • Eugene OR
  • Now: 1987 K75S Then: 1981 CB900F

Offline John Lang

  • ^ Proficient Motobricker
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  • John Lang
Re: New guy here
« Reply #18 on: November 02, 2019, 08:30:51 AM »
Question: how does bump-starting pressurize the fuel lines sufficiently for fuel injection?
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  • Ottawa, ON Canada
  • 1987 K75C

Offline Laitch

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Re: New guy here
« Reply #19 on: November 02, 2019, 10:05:15 AM »
Quote from: John Lang on November 02, 2019, 08:30:51 AM
Question: how does bump-starting pressurize the fuel lines sufficiently for fuel injection?
In 2V Bricks, the fuel pump is energized by the Hall sensors; the Hall sensors function during crankshaft rotation. That's why the fuel pump can only be heard for a couple of seconds when the engine doesn't start—the sensors shut down when the crankshaft ceases rotation.
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  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline John Lang

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  • John Lang
Re: New guy here
« Reply #20 on: November 02, 2019, 10:34:54 AM »
So bump-starting requires a charged battery?
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  • Ottawa, ON Canada
  • 1987 K75C

Offline Laitch

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Re: New guy here
« Reply #21 on: November 02, 2019, 11:38:22 AM »
Quote from: John Lang on November 02, 2019, 10:34:54 AM
So bump-starting requires a charged battery?
Not necessarily. A partially-charged battery can energize the fuel pump relay without being able to supply sufficient current to rotate the crankshaft. With a completely discharged battery, bump starting will require a high-functioning alternator that will output enough voltage to energize the relay, the sensors and the rest of the control systems when crankshaft rotation finally occurs. Bump starting also requires luck coupled with slow twitch muscle development when the force of gravity isn't in large enough supply. :-)

The reason third or fourth gear is used for bump starting is that those gears will produce more rotations of the crankshaft in a shorter period of time than first or second gear. More rotations equal more current pulsations to the plugs and injectors and that equals greater possibility of ignition when the clutch is engaged, if the engine isn't a clapped-out piece of scrap that has never run well.
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  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline The Mighty Gryphon

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Re: New guy here
« Reply #22 on: November 02, 2019, 11:57:23 AM »
[quote author=Laitch link=topic=13060.msg116092#msg116092 date=1572709102

The reason third or fourth gear is used for bump starting is that those gears will produce more rotations of the crankshaft in a shorter period of time than first or second gear. More rotations equal more current pulsations to the plugs and injectors and that equals greater possibility of ignition when the clutch is engaged, if the engine isn't a clapped-out piece of scrap that has never run well.
[/quote]

Wow!  This is a notable day.  The very first time that Laitch has been mistaken in all of the posts I've seen.

Bump starting is not done in first or second because the revolutions of the engine are greater per revolution of the rear wheel in first and second than in the higher gears.  So high in fact, that the wheel locks up when the clutch is released.  Tired, old guys like me need to bump start in fifth to further reduce the resistance to our efforts.

It's also a very good idea to keep the throttle closed, not only to prevent flooding the engine, but to minimize the amount of air being squeezed on the compression stroke.  A very important consideration when an old guy is pushing the bike.
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  • 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 johnny

  • TrailBrakingThrottleWhacker
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  • Whacking...n...Chopping Sliding...n...High Siding
Re: New guy here
« Reply #23 on: November 02, 2019, 12:01:29 PM »
greetings...

that aint laitch... thats an impostor...

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

Offline Past-my-Prime

  • ^ SuperNatural Motobricker
  • Posts: 501
  • All of us are better when we're loved.
Re: New guy here
« Reply #24 on: November 02, 2019, 12:02:06 PM »
Quote from: The Mighty Gryphon on November 02, 2019, 11:57:23 AM
[quote author=Laitch link=topic=13060.msg116092#msg116092 date=1572709102

The reason third or fourth gear is used for bump starting is that those gears will produce more rotations of the crankshaft in a shorter period of time than first or second gear. More rotations equal more current pulsations to the plugs and injectors and that equals greater possibility of ignition when the clutch is engaged, if the engine isn't a clapped-out piece of scrap that has never run well.


Wow!  This is a notable day.  The very first time that Laitch has been mistaken in all of the posts I've seen.

Bump starting is not done in first or second because the revolutions of the engine are greater per revolution of the rear wheel in first and second than in the higher gears.  So high in fact, that the wheel locks up when the clutch is released.  Tired, old guys like me need to bump start in fifth to further reduce the resistance to our efforts.

It's also a very good idea to keep the throttle closed, not only to prevent flooding the engine, but to minimize the amount of air being squeezed on the compression stroke.  A very important consideration when an old guy is pushing the bike.

From my experience, a completely dead battery won't do it. Even for the alternator to work, there needs to be some juice for the field wiring. At least that was my conclusion as a non electrical genius. Best to use a hill rather than pushing especially if you are on your own.

Even better is starting by pushing that little button by your right thumb!!  :1thumbup
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  • North Shore of Lake Superior (in my garage)
  • BRICK: 1989 K75 RT - Rocinante; NON-BRICK: 2007 F650 GS Dakar - Betty Blue
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