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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: lalilulelo on February 05, 2016, 11:20:06 AM

Title: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 11:20:06 AM
Hi guys, im from Sweden and this is my first build ever, i recently found this forum and have been reading a lot of threads here and finally decided to post the progress of my build here to. Normally i hang out at a Swedish forum but the community here is a lot more experienced and appreciative when it comes to these bikes so i figured i can share my story here to.

I think im going to have a hard time explaining what i've been up to when it comes to the bikes different parts since i dont know all the english words. I've also noticed that there are a lot K100 enthusiasts that dont like when we "destroy" the looks of the beautiful stock K100, im sorry if this thread is gonna get you upset.


I got the bike for 13000 SEK, should be around 1300 Euro and its a K100LT

Started off by stripping the bike
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 05, 2016, 11:28:36 AM
Welcome, lalilulelo. Somebody will want all those discarded parts to restore an old brick so it all comes to a balance in the end. Good photographs!
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 11:33:36 AM
Working on fitting the saddle, welded on some metal plates and some "pipes" where the screws are going through, the saddle stays at its place perfectly. Also removed the "steering" (haha sounds so bad) and installed some clip ons. Also cut off a bit from the frame so the saddle looks better on
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 11:40:37 AM
Installed new grips on the clip ons and removed the tires so i could have the rims for repainted.

Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 11:46:50 AM
So i bought a pair of nice LED turn signals for the rear of the bike that i wanted to fit in the frame, to my suprice they didnt work, after some searching i ended up here at motobrick where i found out that the relay box must be opened and the circuit board must be modified. I really dont know how you guys managed to bend it up with screwdrivers so me and my mate opened it up with a dremel and then put it back together with a glue pistol.

Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 11:53:12 AM
So i decided i wanted the frame repainted and also the forks. Took everything of the bike so whats left is the motor and the swingarm. Also cutted of a lot of metal pieces that were on the frame which were useful when the bike was in its stock mode.

Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 12:01:25 PM
I got the frame, forks, rims and front fender back from the painter, paid 430 euro for all of it, dont know if i made a good deal but it felt like it. I decided i wanted everything in matt black and im pretty happy with the result, i also made the front fender half the size by cutting it off in the front and the back, think it gives a more rough touch to the bike. I also bought some fork boots/gaiters and had them installed, i didnt have any clams/stripes at the moment but that will also come so the fork boots stay at their place. In the pictures you can see my new rear sets, i forgot to take focused pictures of them but they can be spotted, gave the bike a nice touch to.

This is how far i've come so far, i'll keep you guys updated, i think the next time will be in the beginning of march.





Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 12:48:15 PM
Welcome, lalilulelo. Somebody will want all those discarded parts to restore an old brick so it all comes to a balance in the end. Good photographs!

Thank you! I have already sold most of the parts and god rid of the rest, i still have the saddle and the rear fender though.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 05, 2016, 12:52:12 PM
When did you start this project, lalilulelo, or did it only take you 51 minutes because you, your mates and the painter were drinking Swedish coffee by the liter?
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 05, 2016, 01:59:53 PM
When did you start this project, lalilulelo, or did it only take you 51 minutes because you, your mates and the painter were drinking Swedish coffee by the liter?

Haha good one! I bought the bike in September and this is what i've managed to do so far, im borrowing my mates garage so i cant work as much as i want to do with it so instead of saying that this took 5 months to build i would like to say it have taken 30 hours so far, i've been documenting all the sessions.
Title: Re: A Swede and his BMW K100 build
Post by: Elipten on February 05, 2016, 08:59:14 PM
On that relay box. All you had to do is run a razor around the bottom edge to cut the silicone and then pry out the board as there are two tabs that hold it in place
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 06, 2016, 08:17:46 AM
On that relay box. All you had to do is run a razor around the bottom edge to cut the silicone and then pry out the board as there are two tabs that hold it in place

I'll keep that in mind if i work on a K100 again :)
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 08, 2016, 09:37:22 AM
By the way guys, i was wondering, me and my mate tried to remove the fuel cap but we didnt manage, and it felt like we had to use a lot of force so we decided to put it on hold since we didnt want to damage the fuel tank.

Any tips on how to do it easily?
Title: Re: A Swede and his BMW K100 build
Post by: billday on February 08, 2016, 10:30:51 AM
Just a general question.

Why are people making "cafe racers" out of K100s? The classic K is a terrible platform for the "cafe" genre: It's heavy (both literally and visually), the engine is loaded with peripheral systems that it needs to run (not least the radiator, which is the most un-"cafe" thing you can have on a "cafe racer"), the frame is not elegant or visually interesting . . .

No disrespect to lalilulelo or anyone else's efforts, but I am genuinely puzzled.

By the way guys, i was wondering, me and my mate tried to remove the fuel cap but we didnt manage, and it felt like we had to use a lot of force so we decided to put it on hold since we didnt want to damage the fuel tank.

Any tips on how to do it easily?

To answer your question, those screws bond with the aluminum tank. Make sure you're using a screwdriver that exactly fits the head of the screw, and give the screwdriver a few firm whacks with a hammer to break the corrosion. Press down hard on the screwdriver while backing out the screws.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 08, 2016, 10:33:31 AM
. . . we had to use a lot of force so we decided to put it on hold since we didnt want to damage the fuel tank.
Holding off was a good move. :clap:

I'd modify billday's approach just a little.
If it were my bike, I'd trickle some penetrant around each fastener, put a screwdriver on the head of each fastener and rap it a couple of times, put the screwdriver on the bench, wash my hands, pour a cup of coffee, use a heat gun to warm up a cider doughnut to eat, read a chapter from an Archer Mayor—or perhaps in your case, Henning Mankell—novel, play some handball or do something else productive for twenty minutes, return to the bike, put on my gloves, rap the fasteners a couple of more times then work the wrench back and forth, bit by bit until the fasteners loosened. Repeat if they don't come loose the first time.

Patience will work in this case, as it does in many other cases.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 08, 2016, 11:06:01 AM
Why are people making "cafe racers" out of K100s? The classic K is a terrible platform for the "cafe" genre: It's heavy (both literally and visually), the engine is loaded with peripheral systems that it needs to run (not least the radiator, which is the most un-"cafe" thing you can have on a "cafe racer"), the frame is not elegant or visually interesting . . .

No disrespect to lalilulelo or anyone else's efforts, but I am genuinely puzzled.
My guess is it's a satisfying artistic challenge that—unlike products from a potter's wheel—results in art that makes a lot of noise while raising the artist's pulse rate, and reinforces the age-old proposition that just because she's not cute to you doesn't mean she's not hot to me. :hehehe  Anyway, it's way better than neglecting the bike, or trying to remodel people instead.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 08, 2016, 11:27:07 AM
No harm done, the K100 has a good reputation of being a nice cafe bike, i can agree with u when it comes to the radiator but in overall thats not a issue when u have the solid K engine that just keeps on going no matter how old it is which can be a problem when it comes to other manufacturers.

Besides the BMW's excellent reliability the big front Fichtel and Sachs Forks are very good (rarely see K builders replace the front forks while other brands very often get the front fork changed), it has a MONO suspension in the back which is beautiful in cafe ways, the bosch electronics and brembo brakes.

Just google BMW K100 cafe racer or scrambler and you will se some nice bikes, then again beauty is in the eyes of the beholder.



Title: Re: A Swede and his BMW K100 build
Post by: The Mighty Gryphon on February 08, 2016, 11:48:45 AM
While I may poke some fun at the builders of cafe bricks, I must admit that some of them are quite attractive and have a certain look not found in cafe versions of other machines. 

The one thing that always catches my eye with these conversions is the unfortunate upward swept angle at the bottom rear of the fuel tank.  Hardly any of the builders address how this angle clashes with the horizontal lines of the seat and cafe tail cowl.  In all the photos I have seen of these bikes I can only think of one or two where this has been addressed by simply raising the front of the tank a few centimeters.   The effect on the overall appearance is dramatic.  I wonder why more builders don't do it when they expend so much effort in other areas.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 08, 2016, 12:02:34 PM
I wonder why more builders don't do it when they expend so much effort in other areas.
I think it's because they embrace Cubism. My bike sure strikes me as an example of it.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 08, 2016, 05:14:51 PM
Im thinking about buying an anti gravity battery, the 8 cell type, does anyone have experience when it comes to these batteries and the K-bikes? Read somewhere else that maybe the voltage regulator needs to be changed so the battery doesn't get destroyed.

Anyone with some experience on this?

http://shop.antigravitybatteries.com/antigravity-batteries-ag801/
Title: Re: A Swede and his BMW K100 build
Post by: Martin on February 08, 2016, 06:31:00 PM
I wouldn't buy one, if let it go it would float away :hehehe
Regards Martin
Title: Re: A Swede and his BMW K100 build
Post by: rbm on February 08, 2016, 07:58:17 PM
The one thing that always catches my eye with these conversions is the unfortunate upward swept angle at the bottom rear of the fuel tank.  Hardly any of the builders address how this angle clashes with the horizontal lines of the seat and cafe tail cowl. 
Exactly Gryph. Only one builder has ever addressed the tank and that's the Kaugusta (at www.Specialks.net).  Larry took an Italian inspired tank and placed it on the K100 frame.  More builders need to ditch that monster and replace it with curvey beautifully formed tanks that accentuate the motor and body.
Title: Re: A Swede and his BMW K100 build
Post by: The Mighty Gryphon on February 08, 2016, 10:39:19 PM
Rob, I recently saw photos of, I think, a German build where the front of the tank had been raised a couple centimeters.  The lines of the bike were so much better.  Lost some fuel capacity, but with cafe seats who goes more than a few miles at a time anyway.  Wish I could remember where I saw them.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 09, 2016, 05:33:47 PM
Asking again about the battery with some more info.

I Emailed antigravity regarding if their batteries work on the K100 and this is the answer they gave me.

"for your BMW we would definitely size you up for a 12-cell battery for that size of an engine as long as your Voltage regulator is reading at the appropriate volts which is no higher than 14.5 volts and using a Lithium or Liefpov4 charger."


Google around a bit for the Voltage Regulator on stock BMW and they seem to be handling between 14.1-14.5 Volts, anyone who can verify this?

Then i dont know if it is using a Lithium or Liefpov4 charger, whatever that is, anyone who can enlighten me on this?
Title: Re: A Swede and his BMW K100 build
Post by: The Mighty Gryphon on February 09, 2016, 05:41:20 PM
I am assuming that Antigravity is a trade name for a lithium battery that can be mounted in any orientation.

It sounds like the battery is designed to be used with an automotive alternator.  For an external charger it sounds like they want you to use something that is designed for charging lithium batteries.

Can't speak to the no load output voltage of the Bosch alternator, but it should be pretty easy for you to find.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 09, 2016, 06:28:48 PM
Then i dont know if it is using a Lithium or Liefpov4 charger, whatever that is, anyone who can enlighten me on this?
This refers to a charger dedicated to lithium batteries when you're charging the battery off the bike or when its not being run regularly. Ordinary trickle chargers aren't recommended. Anti-gravity sells these chargers.

BMW should be able to verify the regulator output. You can test it yourself with a multimeter—plenty of Youtube and Google information available. If BMW can't—or you can't—just ask a bunch of strangers then pick the answer you like.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 09, 2016, 08:16:16 PM
Then i dont know if it is using a Lithium or Liefpov4 charger, whatever that is, anyone who can enlighten me on this?
This refers to a charger dedicated to lithium batteries when you're charging the battery off the bike or when its not being run regularly. Ordinary trickle chargers aren't recommended. Anti-gravity sells these chargers.

BMW should be able to verify the regulator output. You can test it yourself with a multimeter—plenty of Youtube and Google information available. If BMW can't—or you can't—just ask a bunch of strangers then pick the answer you like.

Oh i see, so they were giving me advice on how to charge the battery externally if i needed to do that even though the anti gravity batteries should last up to 1 year. Thanks for clarifying this!
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 09, 2016, 08:34:06 PM
Anicca permeates everything, including Anti-Gravity batteries. They are light though.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 09, 2016, 08:37:21 PM
Anicca permeates everything, including Anti-Gravity batteries. They are light though.

Dont really get what you're trying to say mate.
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on February 09, 2016, 08:43:13 PM
Nothing is going to last, even Anti-Gravity batteries are going to need to get charge sometime.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 09, 2016, 09:13:42 PM
Nothing is going to last, even Anti-Gravity batteries are going to need to get charge sometime.

Yes of course, they just confused the crap out of me when i asked if the battery will fit my bike and they started blabbering abouth Lithium and Lifepov4 and so on.

It seems like the voltage regulators on the K models are between 14-14.5 Volts and that should be within the Anti Gravity batteries limitations, im just curious about since it is a old bike if it will "slaughter" the battery faster. Read some were that one should buy a MOSFET regulator to keep that powerful battery in line.

I mean since the bike didnt know what to do with a LED signal from an indicator without modifications maybe the voltage regulator needs modifications to?

This is just me thinking.. 
Title: Re: A Swede and his BMW K100 build
Post by: enb54 on February 11, 2016, 11:29:22 AM
These batteries must not ever be overcharged, so it is important to ensure your electrical system is OK for whatever brand of Lithium exotic metal battery you use. Google LiFePO4 battery and LiFePO4 charger, plus a quick read of https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery will likely put you on the correct technical track, or you can ask someone who has used them on their machine. I have familiarity with them in communications electronics, but not vehicles... they are fussy but very light...
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 24, 2016, 01:17:27 PM
If anybody see's this and use an antigravity battery on their K bike feel free to add some information :)
Title: Re: A Swede and his BMW K100 build
Post by: Andrewck on February 27, 2016, 04:14:57 PM
Love what you're doing with the bike!!  You have me second guessing my seat fabrication...you're looks great and is very straight forward.

On a side note...had my first visit to Sweden last summer and spent just a day in Stockholm...pricey, but what a great country.  Would love to head back and rent a bike to take through those beautiful forests and lakes you have.  Keep up the work on the bike and look forward to seeing things unfold.
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on February 29, 2016, 11:23:42 AM
Love what you're doing with the bike!!  You have me second guessing my seat fabrication...you're looks great and is very straight forward.

On a side note...had my first visit to Sweden last summer and spent just a day in Stockholm...pricey, but what a great country.  Would love to head back and rent a bike to take through those beautiful forests and lakes you have.  Keep up the work on the bike and look forward to seeing things unfold.

Thank you, much appreciated, i like what you're doing with your bike to, already commented on it in your thread :)

Glad to hear you enjoyed Sweden, it is beautiful in the summers!
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on April 27, 2016, 03:34:47 PM
When i dissasembled my bike i ruined the ignition switch, i can still turn on the ignition but i have to use a knife or a screwdriver.

Looking for a new ignition switch with key, i was wondering if i can buy any BMW K ignition switch and will it work with my 91 K100 LT?

There are a lot of them on ebay and some are cheaper so thats why im asking.

Im thankful for any kind of help!


Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on May 01, 2016, 11:27:40 AM
Another question, hopefully somebody knows the answer to this one.

I have connected all the lights now (headlight, backlight, turnsignals etc) and it works fine.

Decided to connect the old breadbox speedometer just to check if the neutral light works right, every time i tilt the gas tank backwards the N light turns on (its the only way to make it turn on). Otherwise i have to hold the clutch down to start the bike, i know that somewhere something is not connected right.

Maybe someone here knows the solution to the problem?

edit : Everything worked fine before we dissasembled the frame for repainting, surely it has to do something with me not connecting all the wires properly?

I recently bought a BEP 2.0 and the bike is supposed to start without holding the clutch when it is in neutral, but the only way to "trick" the bike in to neutral is to tilt the gas tank backwards, does the reserve fuel indicator and the neutral indicator have something to do with each other?

Sorry if im asking a lot of question but i have no idea where else to turn with these problems
Title: Re: A Swede and his BMW K100 build
Post by: Brad-Man on May 01, 2016, 11:18:23 PM
Are you sure you have good grounds after the frame painting?
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on May 02, 2016, 06:48:42 AM
Are you sure you have good grounds after the frame painting?

I cant say for sure that the grounds are good but the bike starts and all of the lights works.

If i recall it right there are two grounds? One for the battery next to the gear lever and one on the middle front of the frame

Is it possible that the neutral switch can get  lit when the gas tank is tilted backwards because of bad grounds?
Title: Re: A Swede and his BMW K100 build
Post by: lalilulelo on May 13, 2016, 10:17:16 AM
So im pretty much finished with the build, the reason why the neutral light wont get lit is because of the GPI that is hidden behind the swing, seems like it is a common problem with the K bikes, many choose to just accept this and hold down the clutch when they want to start the pike. Maybe i look into it sometime when i need to dissasemble the swing but right now it just feels like it isnt worth the time and the effort just to be able to start without holding down the clutch.

Im happy with how it turned out, just need to fix the ignition switch (already on it, soon done), the rear brake light sensor (ordered one of those that were fitted in the k bikes from before 86, fits my rearsets) and also install the registration plate.

I would like to buy a new battery and also change my coolant reservoir to something smaller and get the "triangle" in the frame more spacious and clean, probably something i will do after the summer, right now im just interested in driving the bike :)
Title: Re: A Swede and his BMW K100 build
Post by: johnny on May 13, 2016, 02:23:55 PM
battery needs a gaitor like your forks...

gaitors on naked motobricks... its a trend...

whack...

j o
Title: Re: A Swede and his BMW K100 build
Post by: Laitch on May 13, 2016, 03:11:16 PM
gaitors on naked motobricks... its a trend...
I'm seeing the same trend over at tragkorb.com.
Title: Re: A Swede and his BMW K100 build
Post by: docrocket on August 31, 2016, 04:27:33 PM
Bike looks awesome! Love the black wheels