I've been watching K bikes come on and off my local market for a few years now and have missed out on a few bargains during that time.
Three weeks back I got back from my FIFO job and saw a '91 K100LT on Gumtree. It had been there for 4 days so I assumed it was gone. It wasn't and I got it.
It's all original - including the BMW stereo radio-cassette - but in quite rough shape and not going. Last registered 12 years ago and 102,000km on the clock but badly neglected.

Haven't got it going yet but have had a key made, unlocked and cleaned the "varnish" out of the tank (  - it really does look like varnish, sticky and brown).
The fuel pump was ruined. I think the last lot of fuel may have been E10 as the rubber fuel pump mount had dissolved. I replaced the ruined pump with a smaller AU$72 Bosch unit thanks to advice I read on this forum. I modified the old plastic ring clip to secure the new pump in the tank. I even got the fuel gauge sender working, thanks again to this forum.
I've stripped down the fuel injection system and de-gunked it, have put fresh oil and a battery in and it turns over nicely now and pumps fuel like it should. I fully expect it to run sweetly once I get new injector O-rings and reassemble everything. So far it owes me less than $1200 Aussie dollars.

I love the look of these bikes and the engineering. The fuel injection and ABS must have been revolutionary back in the day. I do think the K100 cafe racers look great but I'm keeping my LT all original. It will never be concourse standard again (while I own it) but I hope to see it with many more kms on the clock soon.
Thank you to this forum for help so far while I have been a guest.
Pete

Welcome Pete,  

I hope things are safe down your part of the country and the fires are not a concern.  

Good news to hear that you are not going to bastardise your new toy.     

Cheers, Dave.

Welcome.

It's always good to see something old and neglected being rescued.

Welcome Pete

Welcome to the asylum.
Regards Martin.

Welcome!  It's good to hear that you appreciate the old girl the way she is and aren't planning on chopping it all up.  Sounds like you are well on your way to having it in top shape. Congratulations!

Thanks for the welcome, and the well-wishes for the bushfire situation in southern Australia.

I replaced the fuel injector o-rings with ones designed for Ford passenger vehicles ($3 for 8 o-rings) and refitted the injectors etc. Pressed the starter and away she went, purring like a 220kg kitten. I'm liking this bike more every day. Cheers

Welcome DiverPete,

Good to hear the resurrection is going well so far. You seem to be using the forum search facility to its full potential which is great - just so many answers to a wide range of issues readily available.

As I’m sure you’ll already be aware, having got her running again, you are likely to be in need of new tyres - many many posts on this topic, but can’t emphasise enough how differently the LT handles with new rubber versus old. It doesn’t matter how good the tread looks - old rubber goes hard and the LT handles like a pig.

You may encounter ABS brain issues too - multiple resets may be needed to clear the faults and perseverance is the key.

Enjoy.

Hi Pete

Just caught your post - how did you go cleaning the tank and injectors.  I have a bike in similar situation and am interested in any product you used to clean the tank etc.

Thanks
Peter

General consensus is fill the tank with white cleaning vinegar and cover any places that need cleaning and let it soak. A scotch pad can be used to get rid of any stubborn marks. Don't use anything sharp, plastic or wood can be used to push the scotch pad into crooks and grannies.
Regards Martin.

Hi peterk666
I've got my K100LT registered and on the road now but haven't ridden too much yet. But it is a nice day here today...
I used a couple of things to clean out the fuel system. White spirit seemed to disolve the black gunk that I think was the rubber parts from the fuel pump mount. It had just turned to sticky tar-like gunk stuck everywhere inside the tank. It didn't seem to disolve in 91 unleaded petrol so I didn't bother to temove every trace of it. I did get it all off the fuel gauge sender tho and it now works again.
I used 91 unleaded petrol to rinse the "varnish" (ancient petrol I think) from the tank. Took a couple of rinses.
For the injectors I used carby cleaner in a spray can. I made an adapter to fit the can to the injector and used 12 volts to open and close the injector while spraying from the can until I got a reasonable looking spray pattern.
I reckon the best thing I did (besides joining this forum!!) was to resist the temptation to energise the new fuel pump until I'd cleaned everything. Pumping the dirty old fuel and gunk through the system would have been no good.
Also that tip from Born Again Eccentric about old tyres was spot on - the tread looks okay but grip isn't there. Thanks for that.