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MOTOBRICK.COM => Welcome To Motobrick.Com => Topic started by: Zfoster8 on October 31, 2019, 11:03:37 AM
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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.
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congrats. nice looking brick, one of the best , but I may be biased.
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Welcome! Thanks for posting the photos. How many miles are on this specimen's odometer?
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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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Laitch,
Odometer is just a hair over 31,000 miles. Still a baby!
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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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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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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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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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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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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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To confuse future buyers don't use the brakes. In emergencies just drag your feet.
Regards Martin.
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Eureka, that's why the front discs were replaced, I'll keep that in mind for the future.
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Lovely color - enjoy your bike - enjoy the club - hesitate to post questions! - check your splines. . . .
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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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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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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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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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Question: how does bump-starting pressurize the fuel lines sufficiently for fuel injection?
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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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So bump-starting requires a charged battery?
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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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[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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greetings...
that aint laitch... thats an impostor...
j o
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[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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greetings...
that aint laitch... thats an impostor...
j o
Thank Goodness!!! That post shattered my worldview.
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third or fourth gear is used for bump starting is that those gears will produce more rotations of the crankshaft
Partly true, in 1st the rear wheel may lock up and you get no rotation. Or you may be of the school that downshifting destroys the transmission in which case you have no option but to stay in a high gear.
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The last time i bumped started a motorbike was about 30 years ago, 1982 Suzuki gs1100gk. I was doing okay considering the weight of the beast but I couldn't quite manage to get enough speed, luckily for me a nice UPS driver jumped out of his truck and gave me the boost i needed to get it going. I've never forgotten that nice gesture. He must have been a bmw owner. Now i try to keep top quality batteries in all my rides. Thumb is easier now. scott.
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A very important consideration when an old guy is pushing the bike.
It not age, it's just as a drummer, you're all about fast twitch. :-)
When it comes to bump starting when batteries were dead, I never considered how dead they were—kind of dead, dead or really dead. I just bumped started the vehicles and kept the throttles up after that. If they weren't relics, they started. When the revs dropped, it was get out and do it over again. The worst car I had for that was Peugeot 404. One flimsy alternator after another. One bad battery after another. I finally traded it for a pair of Justin boots. I had those for twenty years.
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If someone figures out how to install a kick start on a K-bike I am all ears! One thing about dirtbikes, you never have to worry about a dead battery as long as you have a good leg to kick with.
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One thing about dirtbikes, you never have to worry about a dead battery as long as you have a good leg to kick with.
You can still wind up with one that has been tinkered to death though, and wind up with a pulled groin muscle. :-) Public transportation is the way to go.
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One thing about dirtbikes.........
Or a Ural. Though my overdeveloped right leg is making me walk in circles.
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I don't miss kick starters at all. I angle parked my Ducati 450 RT, and on trying to kick start it, it backfired launching the baffles out of the exhaust. The baffles took a chunk out of the tiles 1'' below a plate glass shop window. I grabbed the baffle and took off before the shop keeper emerged.
Regards Martin.
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Woof! Closest i ever came to that was nearly breaking my leg when my '73 Elsinore 250 decided to kick me back. No compression release, but it really needed one.
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When the Starter was playing up in my brick I was bump starting in second. Never had a problem, always started first run.