Hello all. Well it didn't take me long to tap into the 'source' here. 1985 K100RS, it was sitting under a tarp for several months before I bought it with the clutch cable broken. Battery was dead, put in a new one, still waiting for the cable to arrive. Turn on ignition and I get power at the dash and lights. Press the starter button and nothing. There is a relay clicking in the bottom right side of the relay box, not sure if this is starter relay or fuel pump relay. PO says it ran until last June (now Jan). I've fiddled with all the connections but not given it my best effort there yet. Hit them with dielectric grease and worked them a bit, but they did have some corrosion.

My thought is that I may be overlooking a safety switch? Or a bad connection to the starter? Any pointers would be appreciated. I'm going to spend the afternoon on it now, tracing electrical...

clubbie

Hi Clubbie,

First thought would be clutch switch, as it is in series with neutral, ignition and kill switch. So either clutch in or bike in neutral obviously.

If the kill switch is not working you get nothing, however the starter is kind of hard wired such that if the starter relay sticks on nothing will turn it off except disconnecting the battery.

Might be worth removing the starter just to see if it rotates on its own and also worth checking the load shed relay.

There is a diagram here somewhere which relay is what but the starter one is easy as it is 60A and has two screw on terminals.

Regards,

Phil

Solved. Ran a hot lead to the starter from the battery, it turned over, so had to be somewhere in between. Solution - whacked the relay, and presto! First time up and down the street on it, it sure feels different than my '01 R1150RT, much more nimble and feels 'snappier'. Next: fluid dripping out of the clutch push rod, guess I need a seal, but the fluid is milky, so that has me interested. Can the cooling system leak into the tranny?

The answer is NO!
There is no way to have the coolant leaking into the tranny.
Have you checked the oil level in the tranny?
What is the color of the oil?
The milky color may have something to do with the water mixing with oil due to the fact that the push rod seal is bad.

So you mean the water is getting inside the seal from the outside, ie rain or something, and mixing with the oil and getting pushed back out?

Yes this would be my guess.

If the bike continues with its erratic starting ways I suggest a quick and easy peruse of the starter motor to determine if the carbon brushes have dusted up the insides due to wear (they almost all do this). After removal of the long screws holding it together (take note of the way it comes apart) and a quick measurement of the brush's length, a generous squirt or three of brake parts cleaner and a clean rag should have the whole thing humming again when you press the button. If necessary you can buy the brush plate set from Motobins, Motorworks UK or your friendly neighbourhood BMW dealer.

Starter motor brushes and dust can cause all manner of electrical problem unrelated to the motor.
Your starter relay welded together because the battery was low at one time when somebody tried to start it. A common problem. the battery needs to be well up or this will occur.
Finally, if the starter motor drives but there is no response to turning the engine, then it is the starter Sprag clutch. These tend to get sticky with old oil and will not bite.
A good flushing with a good flushing oil and a consideration to use synthetic (semi) with keep it clean.
Should this not work then a major strip to replace the Sprag is necessary.
Ajays.