Old guy with old bike 91 K100 LT

[Cgswssbmwk100]

after 50 years of wanting a BMW, I now have one...for a mater of hours now...  OK just got a ,91 k100 lt, non runner.  Bike has a lot of miles (139,000) and has been sitting for about 4 years (owner had stroke). Good news (I think) is I picked it up for $500. 


Engine will turn over but not fire.


I wanted to get to the spark plugs, but those 3 5mm screws will not break loose.  Covered then in penetrating oil and will find a 5mm bit for my cordless impact.


Not knowing what I was doing I finally got to the battery.  Battery charged up fine.  Engine turns over fine and I couldn’t get to spark plugs yet, so I tried shooting some starting fluid into the air scoop in the front.


Bike fires on starting fluid!!!


So next project is to get the tank off.  Have no clue how to do that.  Seems I need to remove the fairing to be able to get to it.  Have no idea how to remove the fairing (at least so it can be put back)


I have ordered a after market shop Manuel, but of course I can’t possibly wait until it gets here.


Tomorrow I think I’ll go to Harbor Freight and get one of their cheap m/c jacks.  Then I’ll get the spark plug cover off and put a little oil in each hole to help raise the compression.  Also will put a remote harness to hook up a trickle charger.  If I can’t find a way to get the tank off, I’ll syphon the old gas out and replace it with fresh pure gas (E0). I hate the E10 crap they push on us!


One of my biggest problems is I just can’t see stuff with all the plastic


I may not get much further as it’s cold out there and this fat old man has a problem with trying to get up after any time sitting on that cold floor.

[Martin]

Welcome to the asylum. You can download the manual and other information here.  http://www.motobrick.com/index.php/topic,666.msg2009.html#msg2009
Try using a 50-50 mix of ATF and acetone, which is a lot better at freeing frozen bolts. Application of heat using a hot air gun will also help. If the bike starts on starting fluid the problem is more often the pump or connection. When you hit the green button you should be able to here the pump, opening the cap aids in hearing this. Inspect the insides of the tank it should be clear of residue, the black fuel pump damper should be intact. If left sitting especially with ethanol laced fuel the damper can turn to black goo. If it has turned to goo you will have to remove the pump and clean it out by soaking in white vinegar for a week or two and replace the filters . Internal fuel lines must be replaced with EFI submersible rated hose, external lines with EFI rated hose. There is a known problem with the power supply to the pump, it is a four pin connector that resides under the right hand side of the tank. The application of Deoxit will help in cleaning this connection it is also a good idea to clean all the electrical connectors on a Brick that has been left sitting.
Good luck regards martin.

[Cgswssbmwk100]

Thank you, Martian! 


I’m glad to find this forum.  I have tried 4 others and have not gotten any info specific to the BMW.


I’ll keep all updated and will no doubt, have many more questions


Thanks


Craig

[K1300S]

Welcome.

This is the place for brick info.   Just about anything you may wonder about has been discussed and can be found with search.

Sounds like you have a fuel pump problem.   Either no power,  or pump dead.

Definitely get that old gas out.

[Cgswssbmwk100]

The Manuel download are great help!  Looks like I going to need a bunch of really long  long nose pliers to work inside that tank.  I hope someone will post a link for parts in the US.  I guess, because of the work involved to get there, I would like to just replace the whole bunch at one time (fuel pump, lines, and filter)


This is a really long shot, but can anyone recommend someone in the south east Michigan area?  I’m thinking maybe I might like to take the tank to someone and have the fuel pump replaced with out haveing to pay the bmw dealer $600. Just seems like a really small hole toget tools through.  Maybe once I get the tank off I’ll feel better about it!


Thanks again!
Craig

[Filmcamera]

If you remove the whole filler cap assembly you should be able to get your hands inside the tank to do the work.  That is much easier than trying to do it all from outside the tank using long nose pliers.

[Cgswssbmwk100]

Thanks!  Now if only I had my Son to help with his long skinny fingers...


I know this may be a dumb question, but if it’s a ‘91 K100 LT, thats the two valve head, right?  I guess it really doesn’t matter as this isn’t a performance bike, just made me wonder when I saw the “16V” inyour title.  To put it in prospective, I sold my third V Max.  (New in ‘84,  new in ‘93,  and used ‘97 lawn art bought in 2013.  I rebuilt, restored that bike but sold it to make a down payment on the house)


Craig

[The Mighty Gryphon]

Welcome, Craig!   No need to remove more than the seat and the left glove box to remove the tank.  The tank is held in place with two "c" clips at the rear corners.  Pull them out and you can lift the rear and pull the tank back about 4-5" to remove the clamps for the fuel lines at the left front of the tank.  With the lines removed, just carefully pull the tank back and up.

Deoxit and Techron Injector cleaner are the most valuable chemicals for your bike.  You can get the Techron at any auto parts place.  I get my Deoxit on line:

https://www.ebay.com/itm/Hosa-D5S-6-Caig-DeoxIT-Contact-Cleaner-5oz-Spray-D5s-SAME-DAY-SHIP-W-STRAW-D5/262463268105?epid=673512033&hash=item3d1c07a509:g:PS0AAOSwXLpZxTt6

Be careful if you use the ATF and acetone mix.  It's a good paint remover as well.

If you are working in a garage, I have found that a chunk of carpet about 6'x8' under the bike makes it a bit more comfortable when you have to kneel to work on something low on the bike.  I have a 5 gallon bucket with a folded towel for a cushion to sit on when working. 

No need for jack, a stack of 2x10 cutoffs about 9" long under the engine do a good job of holding the front end up when the bike is on the center stand.

Instead of a jack, I would get a kerosene room heater and an electric radiant heater.  I can work in my two car garage in temps down to about 20F with mine.

Get your parts online at eBay.  Just search"BMW K100" + whatever part you need.  There is a lot of stuff there.  If you can't find what you need at eBay or you want to use new, I have found MaxBMW in New England to be a good source for OEM parts. 

http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51750&rnd=07242017

There are many sellers of aftermarket parts as well.  They are listed here at the forum.

Good luck with your bike.  I'm pretty sure you are going to like it when you get it running.

[Cgswssbmwk100]

Ok, every utube vid I have found showthe bmw vibration damper turned into black goo.  Now we are going to get more ethanol in our gas, not less so it seems kind dumb to replace this the OEM part.  Isn’t there someone that makes a replacement part that won’t deslove?


I have found a couple of aftermarket pumps which claim to be upgraded to handle ethanol, (which are also cheaper) but nothing claiming to be goo proof on the damper.

[Martin]

Apparently the damper from Euro Moto Electrics is more resistant to ethanol. They can also supply a cheaper filter screen. http://blog.euromotoelectrics.com/  I am currently running a Chinese fuel pump from Ali express approximately $25.00 US.  http://www.motobrick.com/index.php/topic,10054.msg86054.html#msg86054. However not all Chinese parts are created equal, it pays to do research, if you go down that track.
Regards Martin.

[kris]

I believe I used some fuel line to take place of my black goo. It's worked for almost three years now. You may even find a thread somewhere showing it. You can jerry-rig something so long as it's gasoline-tolerant. Make sure that tank is clean. As was mentioned, if you take of the entire filler cap assembly it's no problem getting your hands in there...unless your Dutch or Slovenian....biggest damned hands I ever saw!