1200 Sport "dead" starter button

Strange no start issue with the 1200 Sport this morning when I stopped for fuel.

This wasn’t the problem most often reported: loud click but starter doesn’t crank. Nothing happened at all when I hit the start button - just as if the kill switch was off (no, it wasn’t that!)

The bike went through the usual idiot lights & sweeping needles thing when the ignition was turned on. It was too noisy to hear if the fuel pump was priming, but I think it wasn’t. The front light was also out - usually the parking light bulb is on.

So it seems like the ECU was just deciding not to activate the starter…?

I have had my V7 Classic do this, when a relay under the seat sticks temporarily. Flicking the kill switch on & off constantly usually sorts it out.

After fiddling about checking battery leads, fuses and the relays accessible under the seat - and the kill switch trick that revives the V7 - it eventually started. The starter button was dead one moment, and the next prod the bike burst straight into life - not the slightest hint of low voltage or struggling starter motor.

Came straight home, and tried the starter 5 or 6 times on a row: flawless.

I can find lots of threads mentioning issues (bad earth, bad connection at battery, the regulation “startus interruptus”) but nothing like this morning’s issue.

Can anyone think of anything to check?

Any strategy better than buying a couple of spare relays (there seem to be 4 relays under the seat, but just 2 different types) and hoping for the best next time I go out on it…?


The two 30amp fuses have been known to cause strange issues when dirty or old. Give them and their holders a clean. They’re getting on in age so probably worth replacing.

Thanks, I’ll give that a try.

The previous owner had put something on the battery terminals. It was blue, and dry & hard (like old varnish). No idea what it is, never seen it before. So I cleaned them up, back to bare metal, and used some battery terminal spray.

Also checked the earths under the starter motor cover, which seemed perfect. Cleaned up anyway.

Now toying with the idea of the startus interrrupus fix (replace yellow wire/pin 3 on starter relay with live feed direct from battery).

I don’t think this relay is the problem, as I don’t think the fuel pump was priming. If it’s similar to the V7 that means the ECU will disable the starter, so tinkering with the relay won’t do anything…?

But who knows! It’s probably worth it as a preventative measure anyway.

Check the relay under the seat that has the diode in it - make sure it hasn’t got water in it or corroded.

Thanks Brian.

Is that the largest of the four relays? Look to be three identical 4 pin relays, and a larger one with 5 pins.

yes, it is 5 pins

I had the starter gremlin a couple of weeks ago, and I now realise I also had it a few weeks before that at the time I shrugged it off as “finger trouble”. I did the starter relay mod today using a 25A fused lead to the battery and 27A rated wire throughout to the solenoid. (Good old Halfords stuff). The solenoid now goes in with a solid “clunk”, so thats good. But still it did not spin. Halfords do a simple multimeter for £8.50, so I bought one of those and lo and behold the battery volts are low. I jumped started easily from the wife’s car, and the battery volts were then at 13.8, so its charging, but I need a new battery, and that should solve it completely. However I may yet change the actual relays and fuses for new ones.

I have an update on this!

Recap: I replaced the starter relay (Gutsibits) and the big injection relay pictured above (Aprilia part no. 895481, from Fowlers), checked & cleaned fuses & holders, cleaned main earth under the starter motor cover, cleaned battery terminals.

I also bought an online fuses holder & wire for the standard startus interrrupus fix, but haven’t got round to doing it yet.

Anyway, after a few weeks and dozens of starts, it had been faultless.

Then it happened again, in the exact same circumstances as the first time: long uninterrupted run at 70ish on the dual carriageway, stop for fuel with a nearly empty tank, fill tank to the brim.

So why does that cause the issue? Theories…

  1. This isn’t the cause, it’s just coincidence that the two occurrences were in the exact same situation.
  2. Filling up & paying takes about the same time. The heat from a thoroughly warmed up engine, with a stationery bike and within this time window, heats the relays to the point that causes the issue. A shorter stop would heat them less; a longer stop would let everything cool down.
  3. Something to do with a full tank (vacuum?) or conceivably even dumping 20 litres of cold fuel onto the fuel pump???

As luck would have it I had the wire fuse holder with me, so I temporarily connected the battery +ve terminal to the yellow wire on the starter relay connector block. Fixed the issue immediately :slight_smile:

(So we can rule out theory no. 3. No surprise there.)

BTW for the benefit of anyone who may find this thread in future:

There are 3 identical relays under the seat, just to the rear of the tank, towards the offside. Easiest to get at if you remove the small bodywork side panel (just one Allen bolt, really easy to get at).

Only one of these has a yellow wire. This is the starter relay.

The yellow wire is the one you cut, and replace with a wire from the battery +ve terminal (into the connector block on the relay) to permanently fix startus interrrupus.

I don’t recommend my temporary fix - shoving a loose bit of wire into the connector block and touching the other end to the battery +ve. It needs two pairs of hands, and if you’re not very careful you may get nasty burns or even set fire to the bike. In my defence, my bit of wire was at least fused.

If you need to identify the injection relay (referred to above), this is the fourth relay - larger and more square in shape.

That yellow wire is a useful switched live for accessories.

When you have your tank off next - check the ignition key/lock cable connector and see if ono of the connectors has burnt out as (if I remember correctly) the pre “startus Inter” fix runs through the ignition switch . It is possible that the warmth from the engine on this block which is located just by the alternator and behind the belt area, plus the current.