Happened again

[Glenn]

So the 2nd time this year my bike has failed to start after a short trip - 5 miles to the petrol station. It started fine at home, got to the petrol station there was a big queue so I turned it off, then when I tried to start it, nothing wouldn't even turn over. After trying for 10 minutes I called BMW Assist, 15 minutes later the local Assist guy gives me a call, I try to start the bike again and it fires up first time as if nothing has been wrong, it was fine for the rest of the day. I had the exact same issue back in April, the battery is charging at 14.4v when the engine is running and sits at about 12.4 with it turned off. Any ideas?

[Glenn]

Just tried the bike again after sitting for 8 days and it starts fine

[sakm]

Sounds odd!

how are you turning it off? are you using the kill switch or the key/ignition switch?

I have known people use the kill switch before and sometimes the contacts can wear out and have the same symptoms

[Glenn]

I turn it off using the ignition switch, (keyless) and not with the stop/kill switch.

[sakm]

I am guessing you have tried all sorts of combinations of clutch pulled in and side stand up etc etc ?

A faulty gear position sensor would stop it starting but pulling the clutch in with the side stand up would then allow it to start

A faulty side stand switch could also do it

obviously it all depends on certain conditions for the bike to start and and it one of them isn't met then it won't start

I think the first port of call would be to get the fault codes read

[Capt Sisko]

This happened to me after I bought a second hand '18 R1250RT last year. Exactly the same, initially the bike starts fine, fill up with fuel or stop for another reason within 10miles, try to start and it feels likes the battery has gone flat. Leave it 20 minutes and it might start like nothing had happened. The other things that happened were computer related. After an episode the clock needed resetting, the gear shift arrow stopped lighting and an couple of other settings related changes. The problem was it was totally at random. One week it was three time, the next not at all.

Back home I read up about it on the net and it's a known, but not common problem. Loads of people offered different 'solutions' but there was no consensus or put your finger on definitive cause. My solution, a new, but heavier duty battery. I knew my bike had be standing for 8 months before I bought it so figured the battery probably past it's best (despite all the test saying it okay).

Since I replaced the battery, not a single episode again.

[Glenn]

Something like this? https://www.halfords.com/motoring/motor ... 39829.html

Yes I get a full reset of the setting, I normally have the speed displayed , I have to reselect it each time it fails to start.

[Capt Sisko]

This one:-
https://brooksbarn.co.uk/products/yuasa ... bs-cp.html

I'll admit it's bloody tight fit, but it does fit*. The reason this is this is heavier duty, and maybe the reason it stopped my starting problem in it's tracks is the higher CCA (Cold Cranking Amps) capacity, 270cca. As far as I'm concerned with a big twin of any configuration, the higher the CCA the better.

*If you do get one of these, they really are a tight fit. Tip, get a thin bit of webbing, when you push the battery in let it take the webbing with it, but leave enough to so can grab the lose ends to pull the battery out. Easy when you know how.

[sakm]

Something like this? https://www.halfords.com/motoring/motor ... 39829.html

Yes I get a full reset of the setting, I normally have the speed displayed , I have to reselect it each time it fails to start.

Ah! then yes replace the battery! you never mentioned everything resets upon trying I would have said battery straight away!

I have had a couple of instances of a similar thing where I hit the starter and nothing happens and everything resets so I replaced that battery funny enough with the one you have linked to here

No issues since

[Doctor T]

My battery at rest is 12.7 volts. A battery on 12.4V on crank will drop to the high 11 volts. May need that bit extra to crank the bike fast enough. Good luck with the new battery

[adey1]

this happened to me last trip out on the bike called recovery and had a 90 minute wait so took the panel off and went to remove the battery and first terminal the earth i think was a little bit loose tighten it up with the screw driver from the tool kit and bike fired straight up , when i got home removed and tighten both terminals with a spanner haven't had a problem since.

[Casbar]

Known problem, but not on every bike. Mine does the same occasionally, fitted a new battery, but still sometimes it struggles to turn over, it sounds like a flat battery. Bizzarly I always pull the clutch in before starting, old habit from days bike would start in gear. But if this happens I start the bike with the clutch out and it starts as normal.

We have a fleet of 1250s and occasionally this happens. Other thing is to ensure the dials sweep and everything is ready to go before pushing starter. But none of the above is a scientific solution

[EasyRider]

This happend to me on my Gen2 Hayabusa. I left it parked up over winter last year. I put the charger on it every week or 2 to keep the battery good (so i thought). When i started using the bike for the first time, it started right up. We rode about 15 miles and stopped for a coffee. I then went to start the bike and it was like the battery was nearly flat. Got the wife to help me bump start it (which was fun) (NOT). Got home took the battery off and went to get it tested. The volts was where they were ment to be. But the amps were not. It turned out there was a couple of dead cells in the battery. New battery fitted and its been fine since.