Hey everyone. I've got an 01 F4i (Euro if they made them differently). Bought it last September at 86 916 clicks or 54 007 miles. Apart from a few minor issues like squared tires and a not adjusted clutch (even though the previous owner bragged about only putting in 100RON fuel etc.), the bike ran well and never had any reliability issues.
It now has 92.5k kms/57,5k miles. Rode it to my grandparent's place on Friday without a single hiccup. Got there at around 10PM, parked the bike in the garden pretty much just like in the picture, rained a bit in the morning but didn't think much of it, it has survived way worse.
Left at around 6PM on Saturday.

After like 10 kilometers, I started having problems with what I'm guessing is low fuel pressure. Holding the bike at maintenance throttle, it would be very jerky and wouldn't just cruise steadily like it always did. I also think the decel pops were more pronounced/happened more often (it has a slip on of probably the ebay brand from the previous owner).
It didn't matter what my speed or RPMs were, it would always do it, sometimes even under heavy acceleration, but it was worse at maintenance throttle. Alongside that, the bike also died on me multiple times throughout the ride. It felt precisely like running out of fuel, sometimes, I managed to get it started while rolling or it jumped back on it's own. Sometimes, I rolled to a stop, then started it without an issue. No blinking codes, the dash looked precisely as it does when you just turned the key with everything in tact, green key light lighting up and everything.
Got off the bike somewhere along the ride, turned the key off and back on, the little whine you always hear when you do that seemed to have a lower pitch and I also think it took longer. That persisted every time I did it. Fortunately, I got it home. But there is still something wrong with the bike.
I should have the means to tear it down to the frame if need be to help you guys troubleshoot, but am severely lacking in the time department due to uni.
If anyone knows what it might be, I'd be very grateful for whatever help you guys could offer. Thanks in advance and sorry for the long read.

 

You got water into tank and wiring.

Remove tank and inspect drains around filler hole verify it vents to drain tubes down by rear shock properly. Dump out petrol and leave cap open to dry for 24-hrs.

While that's drying, inspect wiring for any bare spots where insulation may be bare. Check iffy-looking non-factory tape bundles by unwrapping to make sure there's no broken wires hidden underneath. Go over entire length of harness with hair-dryer to make sure there's no water inside wiring. Unplug all connectors and inspect metal terminals for corrosion. Clean with OxGard or DeOxit.

 

Will get on that asap, thank you.

 

Super late response, sorry. Kinda forgot about the post.
+ terminal connection was loose, installed spring washers and re-tightened