Father & Son 1988 K75S Rebuild

[jay1622]

Hello all!  I am a new member to this forum and wanted to introduce myself. My current ride is a 2005 R 1200 RT, but I have been wanting to replace my old K75S from years ago. Predicated on a great price, I picked this up for my son (13yo) and I to rebuild together. Currently, the plan is to keep digging until we stop finding little things wrong with it and then slowly put her back together.  I will save you from making this a social conversation, and just mention my want for my son to know how things work when he is an adult. If he takes a liking to mechanics, then awesome. But if he doesn't, he will at least know how things work. The best part is, he appears genuinely interested and has enjoyed what little bit we have done together so far.  The bike was picked up with a destroyed fuel system and a gremlin that is keeping the brake light from working whether or not the grip lever is pulled or the brake pedal is pushed. She sat in storage for five years prior to us picking it up. When parked, it was left with a 10% full gas tank. As you can imagine, the inside of the tank is absolutely horrific.  We are still on the fence as to whether or not build it back to original shape or get creative with the frame and turn it into a café racer. Personally, I think I would enjoy bringing her back to original condition. I have a fair amount of mechanical and electrical experience, but would humbly request any insight you all may have with this project as we progress. As for now, we are just bagging and cataloging parts as we dig deeper and deeper. And yes, we are taking a ton of pictures.  We took the panels off last night and gave her a good cleaning. Hoping I can resurrect what's left of the throttle bodies and the fuel injectors. The internal components of the fuel tank had completely rotted away. That includes the fuel pump and filter as you can all imagine.

 I do have quite a few resources at hand, so please feel free to reach out to me in the event you need any reference information. God knows I will be doing the same.   

[Glacial]

Welcome to the forum. Great idea to get your boy involved. Vital life lesson to learn that you can tackle things yourself with some basic knowledge and a systematic approach. Your fuel-related stuff may be in a bad way but the rest of the bike looks in great condition. The K75S looks great as it is, unless you are a design genius, you won't make it look better by doing the cafe thing to it in my opinion.

[Chaos]

There seems to be a rash of K bikes being converted to "cafe style" lately.  Most of these attempts fizzle out after all the non essential stuff is stripped off what is left is an ugly blocky brick.  On the bright side nice original K's, especially pretty faired ones like the S, are going to get rarer and more valuable.

[beemuker]

Wow, what a great Dad. I wish mine had done something like this for me. Instead he sold his '49 Mercury for $250 a year before I got my learners permit. that would have been a nice restore project. Good luck with the project. BTW, I just bought one of those $16 fuel pumps off Amazon that have been mentioned on the forum to have as a spare.
http://www.amazon.com/gp/product/B000C1KJJE?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

[billday]

+1 on Chaos. These "cafe" jobs get more and more alike (or should I say cliched) -- your original was, is and always will be a beautiful machine (as long as it doesn't get chopped up).

[beemuker]

+1 on Chaos. These "cafe" jobs get more and more alike (or should I say cliched) -- your original was, is and always will be a beautiful machine (as long as it doesn't get chopped up).

yep, that's what people say about mine, classy ride.

[jay1622]

We decided today that we will rebuild it and bring it back to its original shape and form.

Thank you for all of the kind replies so far and thank you for being honest. I have a ton of respect for the artistry and know how for all of those who have gone the café route; it just will not be me this time around.

I will be switching over to a different thread in this forum and documenting our progress. For now, this is what is left of the fuel system I had mentioned.

[jakgieger]

My fuel system looked the same three weeks ago...acetone and water to clean the tank, fuel rail, and pressure regulator.  All other fuel parts new including injectors from osidetiger (ebay).  Happy to report it has been running for two days (just got the injectors Friday).  I was able to save the composite ring that holds the fuel pump/dampener.  On my bike there are two rubber strips that insulate the aluminum housing that holds the fuel pump.  These two "strips" were gone and BMW does not have a part #, so we had to use gas hose w/a slit as an improvised dampener between the bracket and the tank wall.  The price I paid for the BMW pump was a joke...there are cheaper options but, I did not find this out until later :dunno http://www.euromotoelectrics.com/category-s/788.htm

[Tuco]

Glad you're not going to chop it up. K75S is a good looking bike!

[rbm]

Nice father/son project.  I have a 7 year old and he has shown no interest in any of my motorcycling enthusiasm.  Time may change that and it would be nice to share that between us.

I think keeping the bike stock and restoring it is the best decision.

Try to save the fuel sender if possible.  If the resistive element is still intact, then you should be ok.  I wrote up an article on refurbishing the fuel sender which you should review.  These senders are almost unobtainium, at least they are an endangered species.

[jakgieger]

 I just purchased a fuel gauge sender unit from BMW (Engle in KC).  I think it was 130$.  It was on "back order", but the inventory (US) said 25 units in stock.  Took 2 wks to get it .