Hi,

A good start to MOT day, the UK's annual vehicle inspection, my 1989 K100RS will not start.

I keep the battery trickle charged and it was on to the last minute.  Dash lights all came on but pressing the green button got no response at all from the starter motor, no clicks or anything, but the speedo came alive and spun up to about 20mph!  The bike was last out about two weeks ago and had no issues on that run.  I did notice that the charger felt warm when I picked it up which was unusual.

Any thoughts?  I am going to check battery and starter motor relay but am unsure where else to go on looking.

Regards
Nigel

Not sure why the speedo should suddenly buck up but otherwise check the earths under the fuel tanks, starter motor earth and also the good old starter motor brushes.

Just to make you feel slightly better; when I went to MoT the Bandit in March, on the way there it blew the front right fork seal and split the exhaust system at the collector. To add insult to injury, the system had no trace of me booking an MoT for that day and as I didn't have a printed receipt with me, I couldn't argue the toss.

Went away, read the Forum, posted the post, and sat down and read about Load Shed Relays, Starter Relays and Starter motor brushes. Felt depressed. Had a cup of tea. Went out again to do my own crude test of the Load Shed Relay and when I powered up the dash and turned on the headlights everything dimmed.  Battery is kaput!

Will rip it out and see if the MOT man will do a quick test on it to confirm.

Regards
Nigel

Nigel T wrote:…

I keep the battery trickle charged …
Nigel

Hello!

Don’t charge the battery for to long, not good !
I just charge once a month over night, that’s it.

Cheers

MOT man ran a battery test and sure enough there was a defective cell and it could only deliver 10.6V.  Kooked!

Ironic, because I try to keep the battery well charged so that I don't get any of the bad problems from start up with a low battery charge and it was put on a very low trickle charge last night to get it ready for going out today.  Never mind!

Regards
Nigel

Battery chargers have come a long way. You can now get smart chargers that check the state of the battery and charge accordingly.
Regards Martin.

If you've not bought a battery yet, these are great. I bought the other one, it kicks the motor round in a most pleasing manner. It was also the cheapest I could find away from the somewhat suspect ride on mower batteries.

The ABS faults have disappeared too, which is nice.