[videodima]

Update 2 - The motorcycle dies after it gets warmed up, I have posted a video in post #19 that shows the bike dying and I do not touch the throttle at all, the idle was totally stable until it died, and it ran for 12 minutes. If I left the bike cool down, it works again.

Update - check post #12 for more videos

Biked died after about 10 minutes of riding, I am able to start it back up and give it throttle for 5-10 seconds, and then less and less until it doesn't start anymore.

Feel like a classic battery dying, except the voltage is totally fine, and when the bike is running the Volts go up to 14.5 so it looks like its charging too.

I bought a battery to see if the battery was the problem like mentioned in F800ST Starting problems

And the exact same problem persists. When the put the new battery in, the bike worked fine and started up with no issues, none of the gauge needles moving back and forth. But still died 5-10 minutes later

Oh also I can feel a lack of throttle for a few minutes before the bike ultimately dies.

Any ideas? Here are some youtube clips I took, the dash turns on and off sometimes, and sometimes the backlighting for the cluster doesnt turn on, again, seems like a bad battery but both batteries' voltage is a-ok and at 14.5 while running so its getting charge. If I trickle charge the battery, the bike will work again for a few minutes. So again seems like its a battery, but if the charging system is working shouldnt the bike still work? Also the second battery is having the same exact issue.

 

[Pat H]

Sounds to me like a fuelling issue. Possibly pump or regulator. But it could also be the charcoal canister that allows the tank to breath clogged up.
A test is to run the bike till it stalls. Open the petrol cap and see if there is a vacuum there. leave the cap opem and restart the bike and see if it will rev and keep running.
If its still an issue I'd suspect the fuel feed.

 

[Richard230]

That is a tough one. At first I was thinking that the alternator and or the voltage regulator had failed. But even if they did the bike should stay running longer than that and you wouldn't be getting 14.5 volts at the battery while the engine was running. So it does sound like a fueling issue. What Pat recommends should be tried first. Those charcoal canisters can fill up with gasoline and clog the tank venting system. But if that doesn't work and if no one else has any better ideas you will probably have to take it to a BMW shop for a repair. They have a factory computer system that should be able to sort out the issue.

 

[ccramerusc]

If it cranks like it did in the first video, then battery isn't the issue. I would check your fuel system first. Turn the key on without starting and listen to hear if the fuel pump is priming the system. If not, test the regulator and then the pump itself.

 

[Headrush]

What everyone else said.
It's obviously getting fuel through but not enough to stop it running out. Check under the seat for any kinked tubes or obvious damage. You have got plenty of fuel in there?

 

[videodima]

Full tank. Also if I charge the battery up overnight, I can ride the bike for 5-10 minutes before the bike dies again.

Also the fuel pump makes the little noise, which I read means its doing ok?

How do I see if theres a vacuum? once I open the tank it just goes away no?

 

[ccramerusc]

Usually a vacuum will form after the tank gets drawn down a bit, so with a full tank, that would be harder to show. But basically all you do is open the gas cap right after it stalled. If there was a sealed tank, and the pump drew a vacuum in the tank, then you would hear or sense air getting sucked in as soon as you crack it open to relive the pressure. Again, a full tank would make this tough to test. However, you could also do a negative test by just leaving the cap open and starting/riding the bike. If you don't develop any symptoms, then there was a vacuum in the tank, so your issue is either a clogged charcoal filter system or clogged roll over valve. I really doubt that this is your issue. If you still get the symptoms, then the issue is in the pump, regulator, fuel injectors, or throttle position sensor, etc....

 

[N4HHE]

Open the gas cap when the engine dies. We are guessing you will hear it suck air.

Try riding with the gas cap open. If it doesn't die then you have a venting problem.

This is a problem that will be more likely when the gasoline tank is full because there is less air above the liquid. Will have to remove more liquid to get enough vacuum to stop the fuel pump from doing its job, which allows more time for air to leak in.

 

[Headrush]

I think you need to plug in an ODB reader and check the error messages. It could be a failing sensor, or a bad batch of fuel. If it rides at all, then I don't think fuel supply can be the issue as with fuel starvation any load on the engine would make it die pretty immediately. The only other thing I can think is maybe this is heat related somehow.

 

[videodima]

The reason I don't think it's the fuel is because when it first died I was at about 1/4 of a tank, so I filled it with new fuel and it stills does it.

But primarily I don't think it's fuel because one of the symptoms of the bike is that the gauges and display backlight illumination goes in and out, during the few minutes I can ride it. So there is guaranteed SOMETHING electrically wrong going on, at least for the gauge cluster, which leads me to believe it's related to the bike dying too.

I opened the gas cap with the dead engine, nothing obvious

 

[Josep Maria]

Maybe the contact key?

 

[videodima]

Ok update with more info and a new video.

The bike will idle indefinitly(nevermind it does not idle indefinitly, it will cut out abruptly after 10 mintues)

The bike will only die when im in motion or applying throttle.

Putting the bike into gear sometimes kills it.

Here is video of me capturing the symptoms, in neutral and in motion.

When I am in neutral I am not adjusting throttle, that is the bike doing that, my hand is steady.

Also at the end of these videos, once I got to my driveway, the bike won't start anymore, however if I let it sit for a few hours it will start again.

 

[videodima]

Another update, it does NOT idle indefinitly, it will idle for about 10 minutes and then completely cut out. I can start it again for about another minute until it cuts out again. After that it will not start, however if I wait 30+ minutes it will start up again.

So something is heating up or building up or something it seems like? I had the gas cap open to let it vent like people said.

 

[ccramerusc]

My new guess is throttle position sensor. That's the only thing I can think of that could cause a jump in idle like that. I bet the potentiometer has some same spots that are intermittent. Those revs are above what the idle air control valve would control.

Sent from my SM-G991U using Tapatalk

 

[videodima]

another update video, died as soon as i did the throttle. If I didnt do the throttle it would have died 20 seconds later anyways.

 

[Richard230]

Could the engine temperature sensor have failed and the computer is seeing an overheating engine whenever the engine is started?

 

[ccramerusc]

Voltage is a little low, but not low enough to be problematic. I generally see about 14.2 volts at idle.

When it stalls like that and is hard to start, try giving it some throttle while you hit the start button. If that gets it going, then that's more evidence that the throttle position sensor is the culprit. You can try the "reset" of it. Not sure how effective this really is, but it's worth trying:
Key on, but don't start it. Twist the throttle wide open and hold it open for at least 3 seconds, then close it and let it stay closed for 3 seconds, then open for 3 more seconds, and keep repeating this 3 times. Then turn the key off and wait about 30 seconds. Lastly turn the key on, let the computer do it's boot up, and start it. See if that makes a difference.

 

[videodima]

Could the engine temperature sensor have failed and the computer is seeing an overheating engine whenever the engine is started?

Interesting

Voltage is a little low, but not low enough to be problematic. I generally see about 14.2 volts at idle.

When it stalls like that and is hard to start, try giving it some throttle while you hit the start button. If that gets it going, then that's more evidence that the throttle position sensor is the culprit. You can try the "reset" of it. Not sure how effective this really is, but it's worth trying:
Key on, but don't start it. Twist the throttle wide open and hold it open for at least 3 seconds, then close it and let it stay closed for 3 seconds, then open for 3 more seconds, and keep repeating this 3 times. Then turn the key off and wait about 30 seconds. Lastly turn the key on, let the computer do it's boot up, and start it. See if that makes a difference.

The voltage when I put the multimeter to the battery is 14.2-14.5, it shows the 13 on the side there only.

When I twist the throttle wide open there is a change in the sound of it trying to start, kind of like a higher pitch, and a little faster, but ultimately it doesn't help start it.

Ill give that a go since I don't have any other ideas

 

[videodima]

Another update. I now believe it has to do with the temperate of the bike akin to what richard said.

Here is a video of the bike dying, without me touching the throttle what so ever. Before I recorded this video, the bike idled for about 10 minutes. you can skip to the end of the video too to see me try to start it again and use the throttle. If I let the bike cool down, it will work again.

 

[Richard230]

The only thing that bothers me about my failed temperature sensor thought is that there is no red warning light displayed on the dash. You would think that if the bike was seeing an overheating situation that there would be a warning light.