R1100S Twin Spark poor starting

[Karl1000]

I have a 53 plate model; it seems to have an intermittent problem of turning over and over before finally starting. This is usually from a cold start, but not always. This has been going on for some time, but seems to have got worse. I recently serviced it including oil, filter, valve clearances, new Irridium plugs etc. The coil sticks were also swollen and corroded, so I have changed these. All connections are good and there is no leakage from the plugs. Once running and warm the engine is fine and is better on fuel than before the service (around 55-57mpg). I have also raised the front end and swung the bars from side to side to see if the fuel rail de-pressurises due to the ignition cable being broken, however, it is fine. Could it be the coil or TPS? Any ideas?

[nab 301]

Any ideas?

Hard to say really. How old is the battery? check the voltage drop when it's cranking.
When was the fuel filter last changed?

[metropolis2k]

I would check the battery and starter motor. It may be that one of them (or both of them) aren't as healthy as they once were.

[Karl1000]

Battery good, spins over really quickly (for a boxer!).....?

[Karl1000]

Just measured voltage across the battery, bike not used since Saturday; 12.5V. A bit inconclusive really. Charging overnight, will see what resting voltage is tomorrow. Don't think starter motor is an issue at the moment (though magnets on my older R11 came away from the main starter motor body.....).

[metropolis2k]

Fair enough, as long as you're aware! Most people on UKGSer who have starting issues replace the battery and it fixes it. I had the magnets come off my GS starter too.

[Karl1000]

Ok, Thanks, think may have to go that way. Will fully charge it immediately before use and see how it goes. if that cures it, then will have to change it.