Usually parasitic power drain is caused by something added to the vehicle.
Or you have an electrical short, but that would manifest in other ways other than just a drain, usually fire.
These days the usual culprit is a USB socket or plug.
In days gone by it was alarms.
Firstly I'd be checking that all USB items are removed or switched off.
Then disconnect any aftermarket alarm system and bin it.
There is very little on a bike unless it's a keyless start BMW/Ducati to take a parasitic draw.
The other option as has been mentioned is to disconnect the battery and see what it drops overnight.
12.7v seems a little high to be a standing voltage, more like 12.4-5 is normal.
Immediately after turning the bike off the voltage will read higher than the standing voltage.
The bike should be left for 10 minutes before you take the standing reading.
If it drops below 12v over night when disconnected I'd suspect your battery is dying, not quite dead yet.
My Varadero has been on only a few very short trips over the lockdown period and the charging system not being the best to start with has likely taken more from the battery than put in and it was dropping to 11.8v over a couple of days.
Honda HISS system does take a small parasitic draw over the first 48 hours after shutdown, then virtually nothing thereafter, but a good charge in the house has topped it up and now holding @12.4v over night.
Maybe a good charge could recondition the battery. (smart chargers are required)
I'd also to a cranking check.
read the voltage when turning the bike over.
If it drops below 9v it's likely a bad cell in the battery and a replacement is called for. It could be used until it stops starting the bike, but this is a time bomb- MartinW took his Wee all the way to Gibraltar, rode up the rock and the bike refused to start to come down as the battery decided at that point to die.