My BMW K100 1984 TURNS OVER BUT NO SPARK CAN YOU HELP

I don't know the bike but I doubt it is much different in principle than many others. The first possibility to consider is whether any immobiliser is functioning properly and is being properly disarmed before attempting to start. The owner's handbook would be a good place to begin...

Once you know the immobiliser is disarmed and power is flowing to the parts it is supposed to flow to, using the circuit diagram, the various supplies and grounds can be checked and using an oscilloscope check the output from the various sensors as applicable (crankshaft, camshaft).

Even though the bike has never been outside it might not have been immune from the effects of damp and condensation that can defeat many moisture barriers. It isn't unusual for electronic unit and sensor terminals to become dull, oxide coated and a barrier to current flow...

I have 2002 road star midnight. I lost completely spark on all 4 spark plugs. Before bike was running OK but sometimes on low RPM while idling would skip a firing on a at least one cylinder making spufff like sound. I put new spark plugs, and wiggled a little coil wires. Bike with new spurk plugs would not fire up at all. Checked for spark on all 4 spark plugs - no spark., not even an electrical I lost completely spark on all 4 spark plugs. Before bike was running OK but sometimes on low RPM while idling would skip a firing on a at least one cylinder making spufff like sound. I put new spark plugs, and wiggled a little coil wires. Bike with new spark plugs would not fire up at all. Checked for spark on all 4 spark plugs - no spark., not even an electrical charge going to spark plug. Went back to coils. Each coil (there 2 of them) has 2 spark plug wires and 2 ignition timing signal wires connected to them. I realized that these ignition timing wires contacts are corroded to the point they would not conduct a charge from the distributor to coil. CLEAN ALL THE TIMING WIRES Contacts on the coils. I did that and bike fired up right away and started running much better without sputtering or skipping a cylinder firing. SO DISCONNECT ALL THE COIL WIRES AND BRUSH THE CONTACTS WITH A SMALL METAL WIRE BRUSH.

if you have good blue spark and it fires when fuel is added externally , then the problem is fuel flow through the carby
have the carby professionally overhauled or get a new carby
make sure that the gasket to the manifold / head is in good condition

ok on that model of bmw you need to change the mass air flow sensor it controlls the injectors that alow it gas i had the same issue with my old bmw

Check the spark plug gaps and set to 25thou or 0.9mm.
Hope that helps

Did you add gas additive and run motor prior to storage? If not Gum in carb could be the problem.If it won't kick over it's either gas or spark.Make sure the battery is fully charged,I have used starting fluid to start hard to start bikes with good results.Use Caution Read Directions.Good Luck

Check the kill switches including the side stand switch, with an Ohmmeter. Good battery? Good fuses" All wires clean and with a solid connection? Check the loom. Any abraded wires? Check the operation of the ignition switch with a volt ohmmeter. Is the bike in neutral and the neutral light is lit up? Get new stock spark plugs.

If still no spark, get CDI system and coils checked at the dealers shop.

Please rate this solution. Thanks burbee904!