What the minimal team to defeat (raid) machamp?

Get an Alakazam. That’s all I would use.

I'm guessing that you are fainting out with that team. It can be done with level 31 Pokemon (maybe less). I use more bulk. More eggys, less espeons.
2-2-2 is a solid team. 2 glass (espeon/Zam), 2 good (Hurricane Dragonite, Gardevior, Exeggcutor ex/Psy or Solar), 2 tanks (As Charizard, Metagross, Slowbro/king). Get ahead of the clock and sit on it. You'll usually know where you stand when the glass breaks. If it isn't going well after the first 2, get out and try again. Usually 1 or 2 dodges at the beginning is all it takes. Good luck.

Try to land at least 2 future sight with espeon/ alakazam. That's important.
Dragonite with hurr is a beast. Especially windy weather.
Last spot a lugia maybe? Best tank against a machamp.
You can do it.

At trainer level 29, you can already power your Espeons and Exeggutor up to level 30.

Moves do make a huge difference. For example, an Espeon with Future Sight will perform far better than one with Psychic or Psybeam. As for the Machamp, Close Combat is a relatively weak and infrequent move, but your team has no chance against Machamps with Dynamic Punch or Heavy Slam.

Non-legendary options for adding more bulk to your team include Dragonite with Dragon Tail + Hurricane, Gardevoir with Confusion + Dazzling Gleam and Metagross with Zen Headbutt + Psychic.

Lol, this is like the third time you ask the same question. To beat machamp at your level you need at least level 30 pokemon with the right moves. Because you don't have alternative pokemon nor TM it's going to be unlikely that you can solo machamp most of the times (when the raid boss has close combat is the only scenario your team is okay).
Luckily for you, the 8th of September there's an event and Moltres will learn sky attack. This is your chance to obtain a legendary that is going to be super helpful within your machamp team.

The most Minimal team would be a Lugia, yes just one maxed lugia and nothing else.

If you are able to participate in Moltres day coming up next weekend, Moltres with sky attack will be a solid machamp tank.

Looked way back to find this post from before.

I have used the following lineup, all L30.5 or below in this order (suffered through [dodge bug] and won with ~3 seconds left)
2512 Espeon ZH/Psybeam (82 IV)
2376 Zam PC/DG (82 IV)
2444 Exegg ZH/Psy (84 IV)
2321 Exegg C/Psy (96 IV)
2409 Exegg ZH/SoB (73 IV)
2409 Exegg ZH/SoB (67 IV)

Now, not many people currently at L29 have a Confusion Eggy. So, you start off weaker than this team. However, the DG Zam is nowhere near the best Zam and the ZH/Psybeam Espy is also pretty poor. So, you undoubtedly can have better Zam and Espy.

Note: this was done before weather boost and TM...but I still have every one of the Pokémon listed above.

Eggy are better at Machamp than a lot of people give them credit for (game press does say they are viable at level 30 though).