After a service, with new plugs fitted, on way to test centre, I had only travelled 20 or so miles, when trike came to an abrupt stop, after the usual checks, connections etc etc , on plug removal I found the plugs were heavily coked up. after cleaning of the plugs, the trike ran for a further 20 or so, before stopping again, same problem.

The trike is now undergoing a livery change to military airbrush, the engine is now been taken out of the frame, which is being powder coated, and the engine cleaned and serviced...soo knowing this fault, before strip down, can anyone give me pointers in the right direction, as to what was happening...and what I can do to eradicate the problem... 1991 BMW K100 ex Northampton Police Bike Engine....

Now that you have 3 posts you can request the password for access to the secret downloads section which has a troubleshooting guide that will help you solve this problem.

Little did i realize it is also found in the Portal section, thank you Holister.

Fouled plugs means its running too rich. Sounds like it could be the coolant temperature sensor. While it's disconnected from the harness, seeing as your engine is out of the frame, you can test each of the contact pins to earth. At 20°c resistance should be 2.5k ohms from pin to engine block. You can check the temp/ohms scale on the troubleshooting page (about ¾ the way down). The link for this is in the middle of the Portal tab.
If you get no reading, ie infinite resistance, the connection thru the sensor body to the engine block is probably corroded.

Another thing you could check is the fuel pressure regulator.

Good luck

Sounds to me that it is oil fouling or poor ignition. Put up a photo of the plugs.

Holister wrote:Fouled plugs means its running too rich. Sounds like it could be the coolant temperature sensor. While it's disconnected from the harness, seeing as your engine is out of the frame, you can test each of the contact pins to earth. At 20°c resistance should be 2.5k ohms from pin to engine block. You can check the temp/ohms scale on the troubleshooting page (about ¾ the way down). The link for this is in the middle of the Portal tab.
If you get no reading, ie infinite resistance, the connection thru the sensor body to the engine block is probably corroded.

Another thing you could check is the fuel pressure regulator.

Good luck

Add the little vacuum pipe from the rear most intake back to the fuel pressure regulator. If perished and leaking it will result in rich running too?