Just picked up a K75 - need input on the plan of attack

[oneplustwo]

Yes, it would be a bear.  Read about the experiences that Shogs encountered trying the same thing:  http://k11og.org/forum/viewtopic.php?t=12040&highlight=harness

Yes, I read that thread.  I'm going to try to keep the FI and related harness in one piece and replace just the pieces for controls and lights and such.

Also, I need to figure out how I'm going to fab a plate under the tank to mount everything to since I want to keep the section under the seat as empty as possible.  Any thoughts about using an aluminum piece vs steel?  I wonder if galvanic corrosion is something to worry about.

[rbm]

Galvanic corrosion has to happen in the presence of an electrolyte, like salt.  Unless you're near the ocean and the air is humid, I don't think that you'll encounter the right conditions to promote galvanic corrosion.  If in doubt about fasteners, then use copper anti-seize.

[oneplustwo]

Indeed... I'm 10 blocks from the Pacific Ocean.  It's not terribly humid and the bike would be kept in a garage so perhaps not a huge deal.  But I have seen it in my solar panel racking which is obviously much more exposed on the roof.  Good call on the copper anti-seize regardless though!

[oneplustwo]

Hi all,

Embarrassed to say it's been more than a year since I made any real progress on the brick.  Now with Coronavirus providing some free time, I'm back at it!

Next step... mounting an aluminum plate to the frame under the tank so I can have a place to mount the m-unit, starter relay, and other miscellaneous bits.

Any suggestions on the preferred method?  I was considering drill and tapping the underside of the frame rails but holes in the frame doesn't sound great.  The other option is zip ties with a ground strap.  A little ghetto, but benefits beyond no holes in the frame are vibration isolation and ease of execution.

[Laitch]

Next step... mounting an aluminum plate to the frame under the tank so I can have a place to mount the m-unit, starter relay, and other miscellaneous bits.

Put them in a plastic box then secure it with Velcro somewhere.

[oneplustwo]

Just found this guy!  This will be super helpful!

[Laitch]

Please post up photos of your installation when it's completed.

[jjefferies]

Hi all,
I got the front end disassembled last night.  Looks like the forks need some work.  One side has zero damping.  The other seems to only have damping on rebound.  Also, the dust caps (the black rubber things that rest of top of the forks) are cracked.  Hoping that they just need to be refilled with oil.

Do some investigation there. I believe that with some of the fork types there is damping in only one side. Sorry my recollection isn't clear as to which kind. The dust caps are just that and not a big concern. I also am restoring a '90 K75. I picked it up back in '13 for my now ex. (long sad story there)  It had spent a bunch of years stored outside out in the Avenues, SF. The frame had some noxious rust, so I stripped it down and had the frame powder coated. Got the engine remounted and the wheels back on and then it sat sadly in my garage the ex having split and taken the dog. I do so miss the dog (and the girl). So for the COVID-19 SIP I restarted the restoration process. Somewhere I got the impression you may be in the SF Bay area. IF so give a holler, as there are a couple of good people around with resources useful for a restoration job. As in I just scored a brand new BMW seat for a K75 for $60.  No promises as always YMMV. Good Luck.

[jjefferies]

Hi, As I've hit a few road bumps on the way to restoring my '90 K75. Here in no particular order:
1. Ignition switch. I had major issues with the electrics until I gave up trying to restore the ignition switch and just replaced it. THE SWITCH, electrical part not the locking mechanism. The switch by itself is USD $40. and is fairly easy to replace, caveat, provided the little screw that holds it in place in the larger housing hasn't rusted in place. If it has proceed with care as the whole switch, housing and locking mechanism are apparently N/A.
2. Locks. If you are working with parts off different bikes then locks can be an issue. The critical ones are: 1.) the ignition switch, 2.) the gas tank lock 3.) the fork lock. All the others, seat, and saddle bags strictly speaking IMO can be faked. There is a very good description of how to fake those by removing the tumbler, putting the key you want to use in the tumbler and then grinding off any protruding lock bits.
3. seats: in the US after some period BMW farmed out seats to Corbin. Corbin in turn will be happy to restore your seat, for about the same price as a new BMW seat. Alternatively if the foam on yours isn't too bad you can find a shop to stitch you up a new skin. Installation while not trivial is not that difficult.

best regards to anyone else doing a restore.

[oneplustwo]

Thx for the tips. I'm using the m-unit blue so I won't need the ignition switch.  Also, no more saddle bags so I only need the key for the tank which is straight forward.  I may have an issue with the seat.  I have one that I bought to match my frame modifications but I'm not super happy with it.  So I may do my own seat pan.  Or I'll just make it work and perhaps adjust later.

[oneplustwo]

I now remember one of the issues I needed to solve... the fuel sender unit is toast.  I don't really care about the fuel level so much since this is going to be a short distance cafe racer.  However, I do need to get the power to the fuel pump.  I've asked smithduck to see if he has any used ones.  Anyone know if there's a way to engineer a solution without getting myself into too much trouble?

[Laitch]

However, I do need to get the power to the fuel pump. 

You should try doing a search of the site sometime.

Two of the wires on the plate will deliver power and ground to the pump. You can adroitly remove the sender leaving those two wires intact then determine if they need patching or replacing. Look here.

[oneplustwo]

Sorry, I should have been more clear.

Both the level sender and the connections for the fuel pump are toast.  I can try to solder new wires on, but the little metal lugs are so small and corroded that I have little confidence in it working over time.  I'm tempted to try drilling a hole through the existing plastic "plug" and epoxying in new lugs (does epoxy react with fuel?)  In my search, I haven't come across any other ideas beyond a new sender unit, thus my question.

[Laitch]

In my search, I haven't come across any other ideas beyond a new sender unit, thus my question.

How about this?

[oneplustwo]

Ooh, that would work.  I've never used one of those before. It looks like only one wire goes through each fitting?  Or can you get two wires to seal through one opening?  I was thinking maybe they have a seal with two holes, one for each wire but the amazon link didn't show that level of detail.  I'll search for similar fittings on amazon in the meantime!

[oneplustwo]

It appears epoxy is fuel resistant so the simplest thing to do would be just to run the wires through a hole I drill in the fitting with epoxy to fill gaps and hold everything in place?

[Laitch]

It appears epoxy is fuel resistant so the simplest thing to do would be just to run the wires through a hole I drill in the fitting with epoxy to fill gaps and hold everything in place?

That sounds simple for certain. 

Regarding the marine coupling—or any other unfamiliar part—I'd email the manufacturer for clarification. In this case that would be Ancor Technical Support. Scroll down and pick one.

[oneplustwo]

Alas, my poor project has been neglected for too long. It’s time to let it go.

If anyone is interested, please let me know. (I’m in San Francisco.)

[jjefferies]

Alas, my poor project has been neglected for too long. It’s time to let it go.

If anyone is interested, please let me know. (I’m in San Francisco.)

Now, Now. Despair not. My last K75 project sat for 7 years between instigation and restart. The bike didn't suffer any significant degradation. I just waited for the pandemic to come along and give me time to get to it.
In the meantime tease us with how cheaply you are going to be letting it go for and how much you'ver already done.

[oneplustwo]

Haha, thx for the encouragement.  If I had the room, I would keep it.  But it's getting in the way of other projects now... namely my track s2000.  So I really do think it's time to say good bye.

This thread is as updated as my progress!  In short, the frame is welded and I have a saddle that to match.  Suspension is sorted and maintenance is all done with new fork oil, serviced driveshaft splines, and so on.  I repainted the fenders and forks and the brackets for the pedals.  The big things to do are the wiring, sorting out the internals of the gas tank, and otherwise reassembling the other various bits (levers and mirrors and such.)  Also, the saddle to frame "interface" needs to be figured out but shouldn't be a big issue.

I was thinking $1500 for the whole kit and caboodle.  I have no idea if that's realistic or not.  But I'm open to offers.  That doesn't include the motogadget bits as those are all unused and probably worth $1500 by themselves (m-unit, motoscope speedo, cable kit, m-switches)!

[Chaos]

alas, the fate of all too many cafe jobs.  If you were closer I might buy it just for the splines!