My father and I are trying to get running and restore a 1986 k100 that’s been sitting in my uncles shed for 16 years. Should be fun.

Welcome

The last brick I got was sitting for ten years.  After sorting the issues it started in a flash.  Because there's so much alloy,  stainless and that, you got a good chance of getting it going, to the surprise of many.

I spose the more prep the better, before pressing the start button.

Cheers We have just replaced the oil ect. Hopefully will get it going inthe next week or so

WelKome.

Link: http://bit.ly/new2kbikes


Smoky starts: If a K bike is left on the side stand or sits for an extended period then the exhaust may be really, really smoky for a few minutes when you first start it. This is due to the horizontal cylinder design allowing oil to seep past the rings into the combustion chamber when the bike is at rest.  It is normal and not a cause for concern.
 
This is especially true for the first few years of Ks production before BMW upgraded the piston rings.


If you have one of these earlier bikes then you can mitigate smoky starts in a couple of ways:
 
1) Always use the center stand if the bike is going to sit for more than a few minutes.
 
2) If you're going to use the side stand, then before putting the bike on the side stand, turn the bike off and tilt it a little to the right for several seconds.  This allows the warm oil behind the pistons to drain back into the sump, leaving less oil in the cylinders to seep past the rings into the combustion chamber.
 
If the bike has been sitting for months or years then it's not unusual to have a VERY smoky start.  Just ride it and the smoke will go away. The BMW owner manual recommends starting the bike and riding off so letting the bike idle to warm up isn't necessary.
 
When I bring a K bike that's been sitting for years "back to life", prior to the first start, I pull the spark plugs and spray some fogging oil into the cylinders.  Then, with the L-Jetronic (EFI computer under the seat) disconnected, I turn the motor over with the starter several times before reattaching the L-Jetronic and trying to start it "for real."  My theory in doing this is that it pre-lubes the dry cylinders before the engine oil gets circulating on the initial startup.  This may or may not actually do anything material to reduce cylinder wear on the initial restart but it certainly doesn't hurt.

With some luck the petrol was treated with Sta-bil or some such product before storaqe, or the tank completely emptied prior. Check the black 'rubber' support round the fuel pump inside of the tank. If it is even slightly 'goopy' you should replace it, and remove any fuel from the entire system, including the fuel injection rail, before cranking it over to start, even with fresh petrol added.

Welcome to the forum from an originally Victorian traveller (Rosebud).

Welcome to the asylum from the north. Electrical connectors tend to suffer when left, it is worthwhile cleaning all the electrical connections. I coat my connections and connectors with dielectric grease, which some say is a no no and leads to bad connections. Your choice on that, but the only connections that have gone bad are the ones I didn't do.
Regards Martin.

Welcome from Brisbane

Thanks guys, doing the fuel tank now. Everything in there is rooted

Welcome Michael