I ride pretty regularly but once in a while, when engaging the start switch, will bike will chug and fail to start. I used to put it in neutral and it turns over robustly and starts right away. Yesterday, however, I was had no luck, thought I was stranded. Waited a minute and it started robustly. I checked all terminals. All nice and tight. Battery is one and a half years old, as is my bike. I’m going to put it on the battery tender, but has anyone experienced something like this? When it does start it’s not like a bad battery. Any thoughts?
Jay Crouch 
2023 R1250RS

If it didn't start, and then you waited a minute and it started robustly it is not the battery. How long has this been going on ... through more than one tankful of gas?

Some of us have hard start issues after sitting for a work day or overnight, and attribute it to summer gas, since this only happens late spring through to fall. My RS is like that ... takes 2 tries to get started. Wintertime it starts instantaneously on the first try = robustly, as you say. All of this is in neutral although my case it makes no difference if the clutch is pulled.

A couple of friends of mine have both had issues when momentarily turning off the engine mid-ride, and having it fail to turn over sufficiently to re-start. Wait half-an-hour and it starts fine. New batteries seem to have fixed it.

(11-25-2024, 07:12 PM)Jcrouch Wrote: Battery is one and a half years old, as is my bike.
Jay Crouch 
2023 R1250RS

If you have a dealer close by, have them load test the battery. The battery has a 2 year warranty.

(11-26-2024, 06:09 AM)colirv Wrote: A couple of friends of mine have both had issues when momentarily turning off the engine mid-ride, and having it fail to turn over sufficiently to re-start. Wait half-an-hour and it starts fine. New batteries seem to have fixed it.

I am confused ... your friends were themselves momentarily turning off the engine mid-ride ...? Why?

Does anyone think there may be a situation of vapor lock. I’m not a mechanic by any stretch, but the fact that it resolves over time makes me wonder about that?

(11-26-2024, 02:26 PM)Grumpy Goat Wrote:

(11-26-2024, 06:09 AM)colirv Wrote: A couple of friends of mine have both had issues when momentarily turning off the engine mid-ride, and having it fail to turn over sufficiently to re-start. Wait half-an-hour and it starts fine. New batteries seem to have fixed it.

I am confused ... your friends were themselves momentarily turning off the engine ...? Why?

Gas stop, food stop or just taking a break.

(11-26-2024, 06:01 PM)Lee Wrote: Gas stop, food stop or just taking a break.

He said mid-ride ... I forgot to put that in my quote (corrected now in my message above). It sounds like they were switching off the engine while riding ...

Heh. I was merely trying to differentiate my friends' problems from cold starts, which are a different kettle of fish!

jcrouch-
Vapor lock has been pretty much eliminated by high pressure fuel injection systems. It could occur in carbureted systems where the fuel lines are heated by heat from various parts of the engine and the fuel vaporizes in the feed lines, as in cars mainly. Higher pressure elevates the point where fuel can vaporize. I've seen it on old carbureted cars that run 5lbs. fuel pressure or less. The mechanical fuel pumps wouldn't pump vapor.

My various RS's have from time to time exhibited the dreaded "double tap" starting where the first tap of the starter button would spin the engine with no firing. Release and hit it again and it fires immediately. What has been described sounds to me like low capacity battery.

Frank

(11-27-2024, 06:12 AM)colirv Wrote: Heh. I was merely trying to differentiate my friends' problems from cold starts, which are a different kettle of fish!

So, by the quoted phrase you meant periodically stopping during a ride, and switching off then restarting the bikes ...? 

Just trying to understand.

Frank,
Thanks for the info on vapor lock. I emailed my independent BMW mechanic. He agrees with the low battery capacity theory. He added that he has replaced the batteries on some late model Beemers with a more robust one with success. Not sure if the symptoms were like mine or not, but that’s what I’m going to do. I ride regularly so the battery gets charged, but that’s what the symptoms point to.
Jay

That’s happened to me a couple of times, starts and then immediately cuts out, but then starts again fine. My bike even cut out mid ride this year whilst changing gear, was luckily on a downhill straight, and it fired up again whilst on the move. We don’t have winter fuel but have wondered if it could be due to using standard fuel rather than super.

(11-27-2024, 11:23 AM)Jcrouch Wrote: Frank,
Thanks for the info on vapor lock. I emailed my independent BMW mechanic. He agrees with the low battery capacity theory. He added that he has replaced the batteries on some late model Beemers with a more robust one with success. Not sure if the symptoms were like mine or not, but that’s what I’m going to do. I ride regularly so the battery gets charged, but that’s what the symptoms point to.
Jay

A search of old threads on the fora will pull up a lot of complaints about the state of batteries delivered with many of the new bikes - especially those that sat a few months before delivery.

I'll also note that my first battery was pretty much zapped before delivery by a bad computer board (picked up by an astute salesman). If not done, you might check for a parasitic drain on the battery.

(11-27-2024, 12:52 PM)Becksy Wrote: That’s happened to me a couple of times, starts and then immediately cuts out, but then starts again fine. My bike even cut out mid ride this year whilst changing gear, was luckily on a downhill straight, and it fired up again whilst on the move. We don’t have winter fuel but have wondered if it could be due to using standard fuel rather than super.

I have used Regular AKI 87 when on long multi-day rides and have had zero issues with performance or starting. I typically put the Midgrade 89 AKI in the RS. My issues with the summer blend (double start after a cold soak, e.g. first thing in the morning or leaving for home after work) is not octane dependent.

When batteries have died on my RS they have gradually gotten weaker until they fail to turn over. Never have I had a hard start and then a robust start, but I guess it is possible and attributable to a defective battery.

(11-27-2024, 08:58 AM)Grumpy Goat Wrote:

(11-27-2024, 06:12 AM)colirv Wrote: Heh. I was merely trying to differentiate my friends' problems from cold starts, which are a different kettle of fish!

So, by the quoted phrase you meant periodically stopping during a ride, and switching off then restarting the bikes ...? 

Just trying to understand.

Indeed. As Lee said - "Gas stop, food stop or just taking a break." If I'm out all day on the bike I tell people I've been "out for a ride" not "out for several rides"!

(11-28-2024, 08:53 AM)colirv Wrote: Indeed. As Lee said - "Gas stop, food stop or just taking a break." If I'm out all day on the bike I tell people I've been "out for a ride" not "out for several rides"!

Thanks - I use the word ride in the same way as well. Thanks also for clarifying that you did not mean "momentarily turning off the engine mid-ride" as in momentarily while riding. Never heard of anyone doing that but hey, on the Internet anything is possible.

It is the word "momentarily" that introduces the notion of a brief period in time (in my mind at least), and is not a term that I personally connote with stopping for a break on a day's ride.

Anyway, we are on the same page now. Hopefully Jay can also get the original issue sorted as well.

(11-27-2024, 12:52 PM)Becksy Wrote: That’s happened to me a couple of times, starts and then immediately cuts out, but then starts again fine. My bike even cut out mid ride this year whilst changing gear, was luckily on a downhill straight, and it fired up again whilst on the move. We don’t have winter fuel but have wondered if it could be due to using standard fuel rather than super.

No engine fault or Limp Mode when this happened?

(11-27-2024, 12:52 PM)Becksy Wrote: That’s happened to me a couple of times, starts and then immediately cuts out, but then starts again fine. My bike even cut out mid ride this year whilst changing gear, was luckily on a downhill straight, and it fired up again whilst on the move. We don’t have winter fuel but have wondered if it could be due to using standard fuel rather than super.

(...or, as us old guys used to experience on occasion after visiting rural gas stations, old/bad fuel.
Under the right circumstances, doesn't take too many weeks for even modern fuel - especially with 10% ethanol - to go bad in spite of additives.
Not a common complaint today, but a lot of time in the old days listening to folks, especialy those with single cylinder, carborated two-strokes, talk about a bike "running badly." A highway trip with a fresh tank of gas was often the quick fix.)

I appreciate the input from you all. So I bought a small “jump start” battery to throw in my pannier just in case, until I replace the battery as an insurance policy. Here’s a new question. Should one use the battery tender connection to use a jump starter rather than clamping directly to the battery (in the unlikely I even need to), or is that wire harness to frail to take the current of an auxiliary battery? Don’t want to find the hard way. If in doubt, I can just jumpstart the old fashioned way if it ever becomes necessary. Just curious anyone has tried that. Thanks
Jay