Strange noise riding in the rain

[kingcharles]

Hi,
The past few weeks I have been trying to figure out where a strange noise comes from when riding in the rain. And just to make it clear, the rattling only appears when the bike gets wet.
What I am hearing is a rattling sound at acceleration from standstill. As soon as I reach a certain speed the sound goes away (or other noise hides it). At first I thought it were little stones which would roll back after braking. Because I noticed that the belly pan cover accumulates small stones. But that was not the case.
Then I thought that maybe it is sparks from the battery because it is only present when the bike is wet.
But I cannot find evidence for that either although I haven't opened the bike up. I mainly used my nose to find a smell of burns.
So my question is does anybody have any idea what could be the source of the rattle I am hearing? It's been raining. Quite a bit lately and it is getting annoying.
Thanks!

[JeffK]

I would check the chain,
Chain wax can be washed away very quikly on narrower chains, also check chain tension.

[kingcharles]

I have checked the chain and it is well oiled. The tension is also good. In this weather I check the chain daily, also because I use a very simple chain oiler and I want to make sure that it works as it should.

If it were the chain then wouldn't the noise also be apparent in dry weather?
The noise also seems to be coming near the front of the bike but with sound reflection off the road that could be misleading of course...

[frodus]

It could be less of a rain issue and more of a lower temperature issue. I've noticed that some of the metal guards in the front rattle a little because there is a small gap. This may be no-gap when warmer, but when it gets wet, since the metal shrinks slightly, it might cause a little rattle.

[kingcharles]

Yes, I have also noticed that the grill in front of the radiator can rattle when I tap on it. But I cannot imagine how a rattle could occur there. Maybe I will remove it for a while to make sure that the grill is not the source.

Speaking of cold temperatures, I had my very first "Regeneration disabled" warning in the dash as I drove off this morning. Glad that I was warned because my bike is always in sport mode and you get used to that regeneration effect!!!
After 5 minutes a "Regeneration Available" message appeared followed by the well known "Cold Battery Cutback"
Winter is coming!

[frodus]

Not the front of the bike, the side metal guards that go right below the batteries. Behind the radiator, between batteries and the bottom of the bike.

[kingcharles]

Aha, well those panels are pretty solid on my bike. Maybe the 2014 was a bit better there?
Today no rattle, the bike was dry, no rain....