BMW R1200RT/R1250RT Forum

Hi all, Dunno if anyone has experienced this problem. About 3 weeks ago I went for a long ride and on returning home I stopped the bike for a moment, whilst I opened the garage door, but when I went to restart the engine it wouldn't. The engine tried to turn but it was as if there was no battery. After trying a few more times, I let the bike rest. After about five minutes, I hit the starter button and the bike fired immediately. I was left puzzled but relieved. I stopped the engine and restarted it a few more times with no problems at all. Following morning I went down to the garage and started the bike a few times, although, this time the bike would not restart after starting it about six times. Again I left the bike to rest about 5 minutes and it then restarted with no problems. Hmmmmm.
I removed the side panel covering the battery and on inspection, saw that the negative pole of the battery was cracked. I replaced the OE battery with one containing the same characteristics (Although not OE). The bike started immediately and so I thought I had solved the issue. I connected my Optimate 4 (Can Bus) charger to it and didn't use the bike for the following 3 weeks.
Last Saturday after 3 weeks, I went for a ride again. The bike started up, as normal, I rode down to the petrol station, filled her up and when I went to start it    the bike would not start again. Off came the battery cover and on inspection, found the new battery well and tightly connected. I waited for about ten minutes and the bike fired up again, as normal. Needless to say, I returned to my garage and forgot about the ride. My bike is an R1250RT 2019. It is very well kept as it lives in a lock up garage. It has 11000km on the clock and has recently had it's 10000km service done. The bike gave no warnings that it was going to behave, the way it did. I normally disconnect the negative lead of the battery after a ride as I do not use the bike regularly but I connect it back a couple of days before using it and then connect the trickle charger so that the battery is always in top shape. The symptoms of the fault resemble those of a dying battery but I do have a new one on now. I also noticed that after not starting, the screen panel resetted itself to the factory settings ie I had to change the language, time, date etc. back to how it should have been.


Anybody out there has a clue on what this problem could be?? I am taking it to the dealers on Wednesday so that they can have a look at it but would appreciate some advice.

1) What is the battery voltage (after charging) before trying to start the bike, (12.4 - 12.6v).

2) When cranking to start, what does the battery voltage drop to, (min. 9.6v).

3) Once the engine is running, what voltage is the alternator supplying to the battery, (14.0 - 14.5v).

4) When the bike doesn't start, what is the battery voltage at rest.

This video explains what to look for, https://www.youtube.com/watch?v=-B8n9arZVyM (voltages taken from the video).

Hi Douglas
You say in your comment the 'new' battery was tight etc,  if you have fitted a new battery then i would get the starter motor checked. On a 19 plate it should still be under the 3 year warranty.
The starters can and do suffer from heat soak, hence it happens when warm but restarts after 10mins of cooling down.

A lengthy thread but scanning through it and looking at the videos indicate that the problem might be with some sort of automatic de-compression not working correctly/valve clearances. Resulting in the starter motor struggling at times and pulling down the battery voltage. Batteries and starter motors themselves have proved to be problematic too.

R1250GS Starting problem | Adventure Rider (advrider.com)

The low battery voltage will probably be the reason for the screen panel requiring re-setting.

Has this occurred after you had your bike serviced ? it could be some sort of diagnostic fault , like the other chap replied it should under warranty get your local dealer to check this out , i have removed my battery on numerous occasions but only had to reset the date and time when i reconnected it .best of luck .

Douglas wrote:I had to change the language, time, date etc.

hammo wrote:Only had to reset the date and time.

Could be the difference between an EU and UK spec. bike.

michaelc2710 wrote: Hi Douglas
You say in your comment the 'new' battery was tight etc,  if you have fitted a new battery then i would get the starter motor checked. On a 19 plate it should still be under the 3 year warranty.
The starters can and do suffer from heat soak, hence it happens when warm but restarts after 10mins of cooling down.

Didn't Dave f1 have a problem similar to this earlier this year at Rivvie services? It got put down to some dodgy brake light he'd fitted drawing too much power if I remember correctly? Sorry I can't be more specific, I was too busy eating my bacon, sausage n egg butty to really care

simbo wrote:
Didn't Dave f1 have a problem similar to this earlier this year at Rivvie services? It got put down to some dodgy brake light he'd fitted drawing too much power if I remember correctly? Sorry I can't be more specific, I was too busy eating my bacon, sausage n egg butty to really care

I can't remember the butty , I was to busy stripping his bike at Rivvie services to get it going again.......  away off to chop a tree down for the fire to warm up the water for tin bath. It's Xmas and it's mine turn to go first why the waters hot

Hi all, many thanks for your comments and really sorry I have not replied to them, these past two days have been manic. Took the bike to the dealers yesterday and they r looking into my problem. Battery was 100% when I started the bike in the morning, to take it to the dealers. 15min later I got to the dealers, stopped the engine and when I tried to start it again the bike would not start. The dealers connected a BMW charger to battery and it gave a reading of 20%. Something is sucking the power from my battery. Annoyingly, the dealers were saying that maybe my new battery (Not OE) is not compatible  :grave:  which sounds like a bit of BS as the brand new battery has the same specs as the OE Exide battery. In fact the battery started to recover its power little by little, which explains why I can restart the engine after about 10min. I tend to agree with one of the comments which highlighted the problem as coming from the starter engine.


Will keep everyone posted with the results. Thanks again.


PS Don't eat too many bacon butties as they contain a lot of cholesterol.  :enjoying: [size=78%] [/size]

Douglas wrote:Battery was 100% when I started the bike in the morning. The dealers connected a BMW charger to battery and it gave a reading of 20%.

What do these %'s mean with respect to the battery voltage.

Douglas wrote:Annoyingly, the dealers were saying that maybe my new battery (Not OE) is not compatible which sounds like a bit of BS as the brand new battery has the same specs as the OE Exide battery.

It's not unheard of for new batteries to be faulty, BMW R1200RT / R1250RT forum - The BMW R1200RT/R1250RT forum even an OE BMW one.

"They couldn’t find a drain, and decided the new battery fitted at Douglas Motorrad Glasgow was at fault!"

Hi David,


Just had an email from dealers that the bike is ready to pick up. They tell me that they have changed the new battery I replaced with a new OE one and that the problem has been solved  ::) . Not sure about that because the replacement battery I used was one with the same characteristics as the OE one. I will go to the dealers tomorrow and test ride the bike b4 I splash out the 143 euros they are asking me for the battery they have installed.


I will keep updating this post with any results.

Douglas wrote:They tell me that they have changed the new battery I replaced with a new OE one and that the problem has been solved.

If this is indeed the case, it looks like new batteries can be faulty straight out of the box as per DaveCly's experience too.

If this is indeed the case, it looks like new batteries can be faulty straight out of the box as per DaveCly's experience too.


I doubt that the battery I installed was bad as my Optimate charger was giving me the green lights, which shows that the battery is fully charged and not faulty.

Douglas wrote:I doubt that the battery I installed was bad as my Optimate charger was giving me the green lights, which shows that the battery is fully charged and not faulty.

Fully charged only means that a certain voltage has been reached. It is not a test of the battery's capacity under load when trying to start the bike. A battery load test or voltage checks when cranking will help with the diagnosis. After a 15 minute ride, the battery had dropped from 100% to 20% and wouldn't start the bike. A kind of test in itself.

An alternative is that the bike's charging system is not functioning correctly to maintain the battery voltage. More voltage checks required, this time with the engine running to check the alternator/voltage regulator output.

This simple short video shows how to battery load test with a multi-meter, Battery Load Test With a Multimeter - YouTube