A no starter after running.

[Kaos]

I am in need of some suggestions or ideas as the following happens.
My k100 (2v) starts, no issues, no weird sounds and runs.
But. It needs to keep running. Or better yet, start again after it ran, which it doesnt; and within this i am looking for the cause of the issue. It takes some time to be able to start again and I do not know why.
Things that have been tested and proven to work:
Fuel pressure, voltage 12.9, spark, injection, fuel lines are intact and no Kinks.
Things that have been done:
New fuel pump, injectors have been cleaned and tested, new sparkplugs, new fuel hoses, new vacuum hose.
Coolant system completely renewed, including the temperature sensor and the radiator coolant valve, Fan works. and the bike is not overheating because even when cold, the bike wont restart after a hour of it being driven.
Now it will start again in a few hours. The time between starting I have turn over but either no spark -however i do not see a reason why it wont spark after running as the battery doesnt deplete and remains at voltage - or no fuel, and because of this I think the vacuum pump isnt playing its part.
I havent depressurized  the fuel system yet which ill probably do tomorrow.
Now I currently can not think of anything else but the vacuum pump and thats where I need some input of you lot.

[Laitch]

Is the fuel pressure regulator what you are calling the "vacuum pump?" My coffee dose doesn't seem to be working for me this morning.
A faulty Hall effect sensor can present the exact symptoms you've described—engine runs well until shut down then will not start until fully cooled. A faulty Hall sensor results, among other things, in a no-spark condition. The troubleshooting guide downloadable from this site has a static test that uses a so-called 12V LED to detect faults. Because the problem occurs after the engine has been running well, I would get her running until it wouldn't start after being shut down. Right then I would do the static test.

[Kaos]

Indeed, pressure regulator is what i ment with vacuum pump. Its not your cafeïne its probably a language thingy.
Anywho. That was the input I was looking for, hadnt thought of that.
Might as well yoink the spare Hall sensor from the spares heap and test run with that.

[frankenduck]

If it quits when it gets warmed up and then will run again when it cools down that is often a symptom of a failing Hall Effect sensor.

Diagnose: https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/hes.diagnose/hes.diagnose.htm

[Kaos]

Thanks franken.
But no, thats not what's happening.
the bike wont start either after it already has cooled down or when cold.
Because of the time gap i am unable to pinpoint it.
My "shop" isnt near my house so at a certain point life needs me outside the garage and because of that i havent been able to test it after 2 hours of turning the engine off and on.
Usually when I check in the next day it starts like nothing happened.

Normally the engine has completely cooled down within 45 minutes. With the rhetoric of the Hall sensor being able to start when cooled down should allow me to start the bike after maybe an hour or so. 2 hours most certainly.

Yet still i will test it with another hall sensor. Better try it when I have one laying around.

[frankenduck]

Put your ear to the tank to see if the fuel pump whirs when you press the start button. If should.

The four pin fuel tank connector has been known to fail.

Dirty ignition switch:
https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/ignition2vclean/ignition2vclean.htm

[Kaos]

It does whir.
My pump is constant because of an M unit.
Ive Installed a new connector because of dead wires.
Already checked the flow with no fuel cap in case of a vacuum.
When checking I see a flow caused by the return hose.
Inner tank hoses are new and (last time i checked) all connected

[The Mighty Gryphon]

Here are two more cents of opinion on your Hall Sensors.

First is that they have temperature affect hysteresis which is a fancy word meaning they need to cool to a much lower temperature to "reset" than what made them stop working.

Second, is that inside their cover the temperature comes down a lot slower than the surface of the engine.  Two hours after shutting down, the temperature at the Hall Sensors can easily still be 40C or higher.

An easy test would be to remove the cover, start the engine and let it idle.  Then use a heat gun or hair dryer on the high setting to heat the Hall Sensors.  If they are bad, the engine will quit even though it isn't fully warmed up.  Then cool them with compressed air and try to restart.

[Kaos]

Thanks. That was worth more than 2 cents.
I like the numbers because they do make sense
Dont get me wrong, i wasnt trying to diminish duck's point, but 2 hours to decrease to 40c wasnt on my bingo list.
Neither was a busted HES, I reckon a first time for anything.
Ill start fidgeting tomorrow (its night time here)
Run a double check on the fuel lines and grab my spare HES for a testrun, as I really can not be arsed to start fuel line work and replace the fuel pressure regulator without having to do so to save the world.

[Kaos]

It was the Hall sensor.
Ive replaced it with the spare I had laying around.
Ran some tests, first on the property which went fine, open road around the garage which provided a huge smile, maybe even an evil somewhat dirty laugh. And then full send mode.
I may now declare the 3rd non runner restored and ready for the open road.

Will there be a 4th? Dont know yet.

[gard]

Thanks for updating what you found. The Hall sensors can have strange symptoms, when mine went there was intermittent missing at speed for a week or so then it would only run (just barely) at idle, I limped home along the sidewalk getting passed by little kids on bicycles.