The deadline is the problem
Scroll any Bali buy-and-sell group and you'll see them: "Leaving Bali, need it gone." "Moving sale, everything must go by Sunday." "Selling my NMax, flying Friday." Every one of those posts is a price cut, because every buyer reading it knows you have a flight. Single items sold in a hurry typically go for around half of what they'd fetch with time, and the fridge you paid 4 million for gets a lowball offer, a no-show, and a second lowball.
That's the maths of leaving. You can't change the flight. You can change who's doing the selling.
Two ways to sell a bike
Fast. The used-bike dealers around Renon and Denpasar buy on the spot or within a couple of days. They pay a dealer price, which is below what a private buyer would give, but it's cash, it's certain, and it's done. If you're flying in under a week, this is usually the honest answer.
Best price. A private buyer, found through Marketplace, the groups, or word of mouth. Give it up to two weeks: listing, questions, viewings, one or two who don't turn up, then a real buyer. Worth it on an NMax or anything over 15 million. Painful on a 9-million Scoopy if you're also packing.
Most people don't get to choose, because they start too late. If you know the date, start the bike two weeks out.
The paperwork buyers check
Any serious buyer will ask for the STNK (the yearly registration) and the BPKB (the ownership book). If both are there and the tax is paid up, the bike sells at the normal price. If the bike is in someone else's name, or the BPKB is missing, or the tax has lapsed, it still sells, but for less, and it has to be said up front. A buyer who discovers it later is a buyer who walks, or worse. Don't hide it. Price it.
Everything else
Furniture, appliances, the surfboard, the plants, the pots, the kitchen. Item by item, each one is a listing, a conversation, a pickup to arrange, and a no-show to absorb. Sold as a lot to a house-clearance buyer, it's fast and cheap. Sold piece by piece to private buyers, it's more money and more days. Small things aren't worth the pickup cost on their own. Bundle them: a buyer who's coming for the bed takes the fan and the lamp.
Or hand it over
This is the job does most often for people leaving. You send one message with the bike, the list, and the date. Your things stay yours until they sell. You set the lowest price you'll take on each item and he never goes under it without asking. Per item, you pick Fast or Best price. He lists in the English and Indonesian groups, talks to the dealers, handles the viewings and the pickups, and pays you within 24 hours of each sale, by transfer, with a statement showing the buyer's price, his 15%, and any truck or transfer costs at cost.
He isn't leaving. So the deadline stops being part of the negotiation.