On starting my 1985 K100RT today the starter stuck on. The bike fired up OK but if if stalled the starter came in again I think it was running all the time. Turned off the Ignition by the key and the starter kept going the only way to stop it was to disconect the battery. Reconnect the battery and the starter came straight in did this two or three times and then suddenly it stopped and all was normal. Started and stopped the bike several times everthing OK. Now I know that if the starter relay stuck in this would happed but it is a new relay and it goes in and out cleanly. I have studdied the circuit and I can not see how this can occur but I am puzzled by the load shedding relay may be this is the cause. Has anyone had this problem? It has me beaten. Thanks
Ive only had this bike a month and it's been one thing after another I'm beginning to hate it.

How old is your battery?
The reason to welded starter relay contacts is to low voltage when cranking.

If you got a good battery, you need to check the connections.....
both positive and ground....at both ends.

Thanks Inge
Battery 3 Months old showing 12+ volts on my meter leads are new (couple of months) and I recently remade the earth connections and checked the posative (used stainless bolts I hate scrappy bolts and bad connections) I did this after being advise that the bikes are voltage fussy. Got the bills from the previous owner for the battery and relay. The previous owner spent £1000 last 12month (I have the bills) so I though I was buying a well sorted bike.

Since the battery is new 12V is a bit low, you should read ~12,6-12,8V.....but it the low temp these day would also affect this.

Much short trips? Not used that often? ...and if, a tender connected now and then?

Checked the charging......should be ~13,8V when engine is reeved.....also check with all possible loads, high beam, heated handles etc. ...to check that the alternator can cope with all normal load, and still be able to charge the battery....could then drop to 13,5V depending on how the bike is equipped.

I agree the battery should be over 12V when it's switched off and when the engine is running it should be holding just over the 13V mark, even under load. I am able to put mine on charge each night in the garage which ensure's that when I jump on it next the battery has had a chance to recover esp as I only have the 32Amp Alternator.

I posted a photo a while back of a starter relay that had the same symptoms as yours, there is a 2 pronged contact inside that closes... mine had done a bit of welding and only one was connecting....

The bike is not used very frequently and is stored at outside ambient temperature I have not checked the voltage with the bike running. none of this ever effects my boxer.

twincarb wrote: there is a 2 pronged contact inside that closes... mine had done a bit of welding and only one was connecting....

From the Bosch catalogue:

eastern_phoenix wrote:none of this ever effects my boxer.

Your boxer got a quite different starter, which don`t use this kind of relay.

Inge K. - you do come up with some fascinating information.

eastern_phoenix - Your problem is definitely the starter relay sticking. Check the starter button on the handlebar isn't sticking. Get a strong light into the starter relay socket check that its grot-free. Check the wiring on the bottom of the socket. Remove and replace the starter relay in its socket several times, this should help clean the wiped area of the contacts. Check the brushes in the starter motor. If none of that works and you've otherwise got good voltage and good earths take the relay back to the shop and get it replaced.

Good luck

GerryP wrote: Get a strong light into the starter relay socket check that its grot-free. Check the wiring on the bottom of the socket. Remove and replace the starter relay in its socket several times, this should help clean the wiped area of the contacts.

The starter relay isn`t mounted in a socket, the main power is through screw terminals and the signal via a connector.

But I do agree with you that arced relay also could be caused by to much resistance at the signal side.

But the majority is caused by to low overall voltage when cranking.