Coil pack has packed up, or has it??

[steve'o]

Happy Christmas all.
Been outside getting the service done on my 2003 1150 GS twin spark done.
As it was warming up to drain the oil, I thought I would just pull off the bottom plug leads to check the coilsticks which are about 5 years old.
New plugs have just been fitted, having just adjusted the valves. (only minor adjustment)
So I pull the left one off, bike keeps running.
Pull the right one off, bike stalls. Bad coilstick on right side I think.
So I swap both coils over to double check, and it still stalls when I unplug the right bottom plug!
Check wiring seems fine, try to start it with both bottom plugs disconnected and it starts fine, runs ok (TB's yet to be balanced after doing valves).
So I plug it all back together and still the same. Stalls when I unplug bottom right but not the left, but will still restart and run ok with the right still unplugged!
So whats going on???
I thought that if the coilstick was bad it should'nt restart easily with bottom plug unplugged?
Thoughts please.
Steve

 

[Ian J Hartley]

Does your bike have two small yellow relays fitted in the front row of the fuse box?

The one on the far left is the load relief relay (standard fit) and the one on the far right is load relief relay 2, use just for the stick coils (additional fit) to provide additional current.

There have been occasions where people have removed the yellow load relief relay 2 along with the blue abs relay thinking that it's part of the abs servo system, which it is not. Without the relay fitted, your bike will still work provided the wiring is sound. But as the wiring deteriates with age, then the current flow to the stick coils will be reduced, and so will the spark. The relay is there to boost the current and the voltage (direct battery voltage) and therefore increase the spark. If you have both yellow relays fitted, then swop them over, and see if things improve. The small yellow and small black relays are all the same contact arrangements, so are interchangeable for test and fault diagnosis.

I don't know the state of your bike, whether it's original or not. So I'm just making a guess. It could just be that the wiring to that stick coil is a bit grotty. Check the connections aren't all green and corroded.