Author Topic: Thinking of buying a K75s for a project, have questions.  (Read 17619 times)

Offline Bee Em Dubbs

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Thinking of buying a K75s for a project, have questions.
« on: December 05, 2017, 03:14:42 PM »
First off, I have no experience whatsoever with working on bikes so what I want to do is very limited. I'm wanting to convert a k75 into a somewhat cafe racer esque bike. I do not need to do a bunch of mods, just basic for now. Would like to remove all the fairing, install a new seat, and new headlight. How difficult is all of this? I have no idea how the seat part will work and if I need a seat pan built. Also not sure how the tail light would be installed.
As for the headlight, I also have no idea how difficult it would be. I'd be fine with the original headlight for now but it seems like that's not possible if I remove the front fairing?


I see a 1994 k75s ABS with 65k miles on Craigslist for $2600. I'm wondering what a good deal would be. It looks to be in great shape, had been regularly dealer serviced, and is registered in "non-op" at the DMV because the collector has multiple bikes and doesn't ride this one often. The seller will also include a set of factory luggage.
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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #1 on: December 05, 2017, 03:24:23 PM »
Here's the bike:







Here's the inspiration:
This is actually a k100. I would want a little longer seat for a passenger and handle bars not so low.



This one is similar.

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Offline Martin

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #2 on: December 05, 2017, 03:48:35 PM »
Welcome to the asylum. It looks like a very clean K75s which in my opinion are the pick of the litter in K's. There are lot of bricks around with damaged body work that make better choices for conversion. It seems a shame to strip it, you might want to ride it as is for a while you might like it. However your choice.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline The Mighty Gryphon

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #3 on: December 05, 2017, 04:10:59 PM »
Welcome!  I agree with Martin that you may be better with an RT model.  The $2600 asking price includes something for the limited edition color which is the first thing you will get rid of when you modify the bike.

If I was doing your conversion, I would be looking for a K75RT or a K100LT.  These bikes are not very popular anymore, and their prices reflect that.  The engines last almost forever if maintained properly so anything up to 60,000 miles will give many years of riding.  Especially if being used as cafe bikes, as these conversions aren't known for being used to cover long distances.

As far as the details of the conversion, there are many here who have built these bikes who may chime in on this thread.  There is also a section of the forum solely dedicated to documenting the various cafe projects of the members.

http://www.motobrick.com/index.php/board,38.0.html
  • 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 duckytran

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #4 on: December 05, 2017, 04:51:37 PM »
Here's an example of a minimally modified K100. I'd recommend you find a naked K75 to start with and do it in stages. That's what I did (http://www.motobrick.com/index.php/topic,8956.0.html). Good luck!
  • Austin, Texas
  • 1993 K75, 1981 R65

Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #5 on: December 05, 2017, 05:04:29 PM »
What's the difference with starting with a k75rt or k100lt or even a makes bike? I'm just assuming if I get picky about what I start with them it'll take a while to find one that's in good condition that's close by. I don't want to drive really far and it doesn't seem like these pop up left and right on Craigslist. If I can get this k75s as a good deal, is there anything wrong with starting with it? I might keep the yellow tank. And the fact this has ABS is a selling point for me.


Any opinions are helpful as I'm a noob here.
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Offline duckytran

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #6 on: December 05, 2017, 05:38:05 PM »
What's the difference with starting with a k75rt or k100lt or even a makes bike? I'm just assuming if I get picky about what I start with them it'll take a while to find one that's in good condition that's close by. I don't want to drive really far and it doesn't seem like these pop up left and right on Craigslist. If I can get this k75s as a good deal, is there anything wrong with starting with it? I might keep the yellow tank. And the fact this has ABS is a selling point for me.


Any opinions are helpful as I'm a noob here.


For me, it just helped to minimize the work involved. I see your point in making the search more difficult if you were to narrow it down to a specific model. Have fun!
  • Austin, Texas
  • 1993 K75, 1981 R65

Offline Laitch

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #7 on: December 05, 2017, 06:46:39 PM »
Would like to remove all the fairing, install a new seat, and new headlight. How difficult is all of this?
. . . is there anything wrong with starting with it?
If you can do research, follow instructions and have patience, you should be able to complete your project. Countless threads here and elsewhere show various ways of doing those jobs. The bikes you have shown as examples do not have their original speedometer and tachometer instrument clusters. They have aftermarket instruments. If you choose to replace yours, you will be learning some basics of wiring and incur some additional expense for adapting the new instruments to the bike.

As has been indicated already, you should look through the Custom bikes section here to get a feeling of what can be involved and some of the obstacles to overcome.

If you buy that S, you should have no difficulty finding buyers here for some, or all, of its fairing and whatever else you might not want.

Before you start the bike and run it, you should know the bike's mileage and how often it has been ridden. If it has been well and recently run, there should be no problem. If that bike has been in storage with fuel in its tank, you won't be doing it any favors by trying to start and run it because decomposed material in the tank might infiltrate the rest of the fuel system. If it has been in storage for a few months or more, you won't really know how "clean" that K really is until you remove the fuel tank's filler cap assembly, all its fuel, then shine a light into its tank and have a look around in there.

It looks pretty good right now though. :giggles
  • 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.
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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #8 on: December 05, 2017, 09:26:38 PM »
Thanks for the reply Laitch (and others). Here is what the owner said so it basically reaffirms what you said. Sounds like he has a huge collection of bikes.


"I occasionally start the engines and let the bikes warm up to keep things from getting gummed up. Batteries tend to go flat and gas loses it's volatility over time and both require replacement or refreshing as necessary. I try to keep the collection in operational condition but I don't always keep to a tight schedule. The K75S will need a new battery (which I will install before sale) and fresh gas. Other than a thin coating of dust, the K75S is as seen in the picture. I also have a set of the factory luggage that I'll include with the BMW."
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Offline Skunky

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #9 on: December 06, 2017, 04:40:25 AM »
Thanks for the reply Laitch (and others). Here is what the owner said so it basically reaffirms what you said. Sounds like he has a huge collection of bikes.


"I occasionally start the engines and let the bikes warm up to keep things from getting gummed up. Batteries tend to go flat and gas loses it's volatility over time and both require replacement or refreshing as necessary. I try to keep the collection in operational condition but I don't always keep to a tight schedule. The K75S will need a new battery (which I will install before sale) and fresh gas. Other than a thin coating of dust, the K75S is as seen in the picture. I also have a set of the factory luggage that I'll include with the BMW."
Personally I would keep the fairing too. If you fitted drop bars rearsets and a custom seat it would make a very cool cafe style bike

http://4.bp.blogspot.com/-fU1s7j0pZWQ/Vfn6EyuK1aI/AAAAAAAAmZA/fyfy9ZZ_DyM/s1600/_N4B7106%2Bcopia.jpg


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Offline tahitianrider

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #10 on: December 06, 2017, 05:41:58 AM »
Welcome ! :)


Quote
Would like to remove all the fairing, install a new seat, and new headlight. How difficult is all of this?


This is actually pretty simple and easy. I was wondering the same thing for my cafe project, as I did not have any power tools. And installing a new seat is not that difficult. Basically and aftermarket cafe racer seat will have mounting holes. They will just not match the holes on the frame of the bike. So I just use a plank of wood in between the 2, with holes for the seat to mount on, on one side, and on the other side, bolts to mount the whole thing on the frame. Super simple :)
Removing the fairings is as simple as removing bolts, and installing a new headlight is also super easy if you order those round headlight with fork brackets where you just have to clip the brackets on the fork.


Here is my project if you want to have a look : http://www.motobrick.com/index.php/topic,10572.0.html


I also made a full timelapse video of my Cafe racer transformation, you can see how I mounted the seat : https://www.youtube.com/watch?v=-oIFhkVYLLI&feature=youtu.be
  • France
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Offline beemuker

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #11 on: December 06, 2017, 08:26:06 AM »
That's a very fair price. I have the same model and color. go get it before someone else does, and have fun with your project.
  • 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 Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #12 on: December 07, 2017, 12:18:06 AM »
Looks good tahitianrider.


I'm hoping to check out the bike this Saturday. Most likely I'd ride it for a while without doing much to it. I think the first order of operation would be a new seat. I'll have to find something I like and figure out how the tail light will work. I'm hoping the bike is in great condition and we can reach a deal.
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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #13 on: December 07, 2017, 10:53:04 PM »
Hello again. I've been watching videos about seats... I tried searching on this site for custom seats but I wasn't coming up with much.
Do people generally fabricate their own seats or are there some trusted vendors that sell seats?


I like the look of this:





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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #14 on: December 07, 2017, 10:57:22 PM »
But this looks more comfy and looks like a perfect fit for the BMW:


And this one fits nice as well:





There is no way I could fabricate my own seat so I'm trying to figure out how the unskilled go about doing it. Also, in looking for a long enough seat for a passenger. Will I need to modify the seat bar at all?

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Offline Skunky

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #15 on: December 08, 2017, 07:00:53 AM »
What you have there is a brand new Triumph t120 with a non standard seat, forks and oversized knobbly tyres. Have you considered looking for a bike that's already had the work done. In all honesty customising a K bike doesn't make it any more valuable and there are plenty of custom jobs for sale where somebody else has already spent the money and done the hard work. Otherwise there are companies like cafe4racer.eu who sell a seat made for the K bikes. For me it's about taking a bike which has been neglected and making it into something loved and hopefully cool. During my project I have taken on so many things I haven't done before, for example I have made my own seat. Iits as much about learning new skills as building a bike. I really can see why some of the people on here appear negative about people chopping up good examples because they love the bikes as they are and they appreciate the value of a good model.

http://cafe4racer.eu/en/upholstery-motorcycle-seats-cafe-racer-scrambler-custom/619-bmw-scrambler-seat.html
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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #16 on: December 08, 2017, 09:19:06 AM »
I know that's a triumph but I just used it as a reference for the seat. I was actually looking at the Bonneville as my next purchase but fell in love with the k. I would consider a bike that had a lot of work done but sometimes people overdo it and the bikes look dumb. I like a lot of aspects on the k bike already so I'm not looking to swap out every part. There is one on Craigslist near me, the only one I can find, and I would never ride it. Allso, no ABS which I wanted.

Also, I've never looked at any vehicles as an investment. So I'm not worried about getting back what I put in. I'd just like a reliable bike that I can learn a thing or two on.

There is a shop near me that rents out their workshop spaces. The owners give advice and can help out build and weld for $40 a half hour. That might be good for things I don't know how to do myself.








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Offline beemuker

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  • '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 Skunky

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #18 on: December 08, 2017, 12:10:42 PM »
saw this on fleabay. cheap enough , maybe it could be modified for your project.
https://www.ebay.com/itm/Motorcycle-Black-Hump-Vintage-Cafe-Racer-Seat-For-BMW-R60-R75-R100RS-100R-GT250/391862123014?hash=item5b3ccd7a06:g:GsIAAOSwulBZjnNJ&vxp=mtr

I think you'll find that's Freabay   :hehehe

At $37 dollars including postage I wouldn't expect quality. Chinese Child labour  :nono
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Rebuild it and they will come..
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Offline Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #19 on: December 08, 2017, 01:50:07 PM »
I saw what looks like decent seats here:


http://www.texavina.com/k75-k100-k1100-late-80s-early-90s/


 Also the eBay seller daytrader-07 has similar seats which it looks like texavina supplies. Texavina has their seats outsourced in Vietnam and that is also where the eBay seller is.
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Offline rbm

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #20 on: December 08, 2017, 10:34:38 PM »
The Triumph design works because the line of the seat flows smoothly into the line of the tank.  The subsequent K-bike pic example you posted looks bad because the seat hasn't kept the line of the tank.  The bottom edge of the tank flows upwards, as does the line of the seat, and they meet in a "V". 


I helped a guy build his cafe interpretation.  He pinstriped the tank and seat pan to emphasize the line and worked hard to make those visually parallel.  He raised the seat pan a few cm in the rear and filled in the space with welded plates. Also, you can visually draw a curve along the top of the tank and smoothly intersect the curved tail. The result is pleasing.

  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline The Mighty Gryphon

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #21 on: December 08, 2017, 11:37:23 PM »
About that tank seat line; a year or so ago, I saw a German cafe conversion where it looked like the tank had been lifted at the front end so the line of the rear bottom of the tank was horizontal.  Looked like a different bike.

I've also seen builders use two tone paint schemes with pin stripes to camoflage the tank angle.
  • 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 Bee Em Dubbs

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #22 on: December 10, 2017, 02:35:44 AM »
Looked at there bike today and it all checks out besides the gas tank. Some rust or something on the bottom of the left side. How big of a deal is this and can it be easily fixed or would I need to buy a new tank?




 
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Offline Bee Em Dubbs

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Offline rbm

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Re: Thinking of buying a K75s for a project, have questions.
« Reply #24 on: December 10, 2017, 07:11:41 AM »
That's a typical long term damage area on these bikes, which will lead to fuel leaks unless addressed.  It's a difficult problem to fix reliably using DIY techniques.  Either a new tank or professional repair with aluminum welding.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

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