Would you?

[Philip]

A new battery will not necessarily solve the 'hot start' issue.
Here's my progress after reporting it to BMW. This is on a sub-3 year old bike (when first reported) - low mileage, good nick, etc.

1. New battery - BMW drop-tested it and found it wanting. I paid for the new battery (wear & tear). Didn't solve it.
2. Extra loom - appeared to solve it, but failed again after approx 3 months. BMW fixed as 'goodwill'.
3. Replacement starter switch. BMW fixed as 'goodwill'. Appears to have solved it. 6 months with no problems so far. Fingers crossed.

I suggest anyone afflicted really has to step1 first, in order to start from a known good base - or at least request BMW test your battery. I don't think you'll get any interest from them unless you do, which I think is fair enough.

I reported it as a safety risk - I stalled it having filtered down a dual carriageway to some lights, and then couldn't restart. I was distinctly uncomfy sitting in the middle, with traffic passing either side. Had to wait for it all to go away before paddling to the side.

There are two distinct different " hot start problems ".

There is the common one where the bike tries to start but just doesn't have enough umph to turn over.
You can hear the starter solenoid click but the motor doesn't turn enough to start the engine.

Then there is the less common one in our climate, where hot sun on the starter switch seems to distort it resulting in it not operating properly.

It sounds like you had two different faults together RT.

The faulty switch in your case probably not due to everheating, but just faulty.
But do agree the fault has to be investigated systematically if you want BMW to cough up.

When the starter switch is faulty, the starter solenoid doesn't even operate, so total silence when the switch is pushed.
But with the " Hot start problem " the solenoid will operate, but there isn't enough power to turn the starter motor properly.

The starter switch is susceptible to overheating in the sun.

I parked up at a cafe with the Old Gitts last year in France, the temperature was into the 30's & the bike was parked in the sun.

After being parked for at least 30mins I went to set off, the starter was completely dead with a weird feeling from the starter switch, the starter switch seemed to distort as it was pushed.

Luckily I had read a post on here a few week previous, where someone had a similar problem due to the sun.

I pushed the bike into the shade for a few minutes, low & behold the starter switch felt normal again & the bike started fine.

The bike still has the same switch 9 months later & hasn't let me down like that again.

So lets be clear. Before you go out on your bike next time, push it into an airconditioned darkened room for 10 minutes, then you can be sure it will start fine LOL.

[Phmode]

It was Steve and it's here
https://eurokclub.bike/index.php?topic=3265.0

Thank you. I've now downloaded both sets of instructions.

And to answer David's point, it's not as simple as a new cable going anywhere...

[richtea]

There are two distinct different " hot start problems ".

There is the common one where the bike tries to start but just doesn't have enough umph to turn over.
You can hear the starter solenoid click but the motor doesn't turn enough to start the engine.

Then there is the less common one in our climate, where hot sun on the starter switch seems to distort it resulting in it not operating properly.

It sounds like you had two different faults together RT.

The faulty switch in your case probably not due to everheating, but just faulty.
But do agree the fault has to be investigated systematically if you want BMW to cough up.

When the starter switch is faulty, the starter solenoid doesn't even operate, so total silence when the switch is pushed.
But with the " Hot start problem " the solenoid will operate, but there isn't enough power to turn the starter motor properly.

The starter switch is susceptible to overheating in the sun.

You're correct, but I wouldn't call both 'hot start' problems.

One is the hot engine start problem, as I described.

The other is hot weather faulty switchgear due to crap switch design, as you described.
The switches are generally poor on early K1300S. Later / replacement switches are better.

The reason to change the starter switch for the hot engine start issue is because a new switch gives a better contact.
I suspect (but have no proof) that it's because there is arcing across the contacts, which causes spark erosion of the starter switch surfaces. A less smooth surface means higher resistance: V=IR and all that.

Don't conflate the two issues!

[Philip]

There is virtually no current flowing through any of the switches on the K1300 switchgear.

The switches all connect to the ZFE or whatever it's called, the ZFE operates whatever has been commanded by the switch, be it starter, lights or indicators etc.

If you take a switch apart, they are similar to TV remote control conductive rubber pads that operate onto a PCB type surface.

[Phmode]

they are similar to TV remote control conductive rubber pads that operate onto a PCB type surface.

...and which are renowned for failing, even with almost no current draw 

[richtea]

There is virtually no current flowing through any of the switches on the K1300 switchgear.

The switches all connect to the ZFE or whatever it's called, the ZFE operates whatever has been commanded by the switch, be it starter, lights or indicators etc.

If you take a switch apart, they are similar to TV remote control conductive rubber pads that operate onto a PCB type surface.

That sounds about right. I stand corrected.
I'll be interested to see if my hot engine start issue has definitely gone in that case, since the switch issue is an aside. Maybe they were changing it in desperation. 

[Philip]

As I said earlier, i'm prety sure you had more than one fault.

They have fitted a new battery, extra wiring & now a new starter switch.

So all bases should now have been covered.

Should be good to go for a couple of years 

[TomL]

I think they replace the starter relay as well. I wonder do they change it for a different type of relay?

[Phmode]

I'm sure someone did the research and said it was a different relay.