Hi all!

Looks to be a really group on here!
Id been looking for a motorbike project for quite some time when i found a rundown 86 K100 for $300. I figured any BMW for that pri ce you dont ask questions and buy it regardless.
It had a horrible lime green paint job and looked like it had been sitting in a paddock for years.
The guy had advertised it as suited for parts as it clearly was far from running and missing a few bits and pieces.
6 months on and ive got get it to the point its nearly starting. Few remaining gremlins that ill be looking for some help on and sharing my experience of it on the way.
Cheers
Hayden

welcome Hayden

have fun with it

lots of stuff in the how- to's  section

good luck

Thanks Charlie,
Has been on of the nicest engines ive worked on, will be starting a build thread shortly

Welcome to the asylum. The Brick engines are probably one of the most bullet proof engines BM ever built. It is worth going over all the electrical connectors and cleaning them with a product called DeoxIT or similar. I go one step further and smear heavy silicone grease around the connectors. The theory is it will keep out water and air that leads to corrosion. It's been working for over 20 years with the only failure been the one connector that was too hard to get to. There is one problem connector that seems to pop up more than others, it is the four pin connector that supplies power to the fuel pump. It resides under the righthand side of the tank, it is the first port of call if power to the pump is lacking.
Regards Martin.

Not surprising that you were able to get it running.

These K motors are bulletproof and will probably still be running long after mankind has become extinct. Only two things will be alive then.  K bikes and cockroaches.

Good on you for bringing one back from the dead.

Good tip Martin, ive noticed that the tank connector on mine seems a bit of a loose fit. Wouldnt be surprised if it rattled loose at some point. Will need to sort something out for it in the near future.

Unfortunately its not quite running just yet duck. Its turning over and firing but she wont run on her own accord yet.
Certainly not wrong about them being bullet proof! I was amazed at the condition of cyclinders on a bike that has early done 150k + kms!!

A lot of inmates replace the 4 pin connector with a waterproof one. Jaycar is one source.
Regards Martin.

Perfect! Will be changing it for sure. The whole wiring harness needs a bit of attention really. Have got some loom tape and braided cable on order at the moment to tidy it up.

How do you know what the cylinders look like?  Did you take the cylinder head off?

The whole bike was covered in dirt and what looked like sand when i bought it. With the throttle bodies off i could see seem of it had made its way inside the motor so took the cyclinder head off to clean it up. The top of cyclinder one looked a bit pitted but relapped the valves so looks like everything is sealing as it should. Replaced the head gasket as well of course

after  a relap job ...might be worthwhile measuring clearances between camshaft and valve shims ...one of the issues on these bikes is that they can  run too tight on the shims ...a relap will just make it worse    aim for something like 6-8 tho on inlets and 8-10 tho on outlets to start with

whilst cold not an issue   but just be aware

often the pump is the issue as stated before   either the connector or actually the pump could be seized ….before going any further aim to replace all fuel lines inside and outside the tank

good luck

Thanks Charlie, good to know! I havent checked the clearances yet but will have to get back to it.
I have replaced the fuel pump on it, bench tested the old one and it was seized. Have also replaced the fuel filter, fuel lines, pressure regulator, fuel rail and injectors (3/4 were blocked, still hoping they might come good for spares if i soak them long enough).
Its getting fuel and spark but not still running. Am picking up a compression tester this week to check the compression

Low compression after a long nap?  Try this:

https://www.youtube.com/watch?v=DerHlx-bO0s

Marvel Mystery oil is great for loosening stuck rings.  I have used it and it freed up stuck oil control rings that were allowing a lot of oil usage.

http://www.marvelmysteryoil.com/

Gryph Marvel is not available in OZ but can be purchased from the US. Cost approx. $15.00 Au for 16 oz plus $32.00 for freight approx. $21.00 Au for 32 oz and $50.00 Au freight approx.
Regards Martin.

That's a shame.  It did a very good job of freeing up my oil control rings.

I put a bit engine oil down the cylinders a few weeks ago but i also had s few other fuel problems then too. Might have a look into a similar product here in Aus and try again.
Cheers