First off welcome to the site Zhengar.
Your Sun team appears to be heavily reliant on Drought, which can be the difference between success and failure depending on who wins the Weather War, you or your opponent. Outside of the Sun, the team appears to be weak against every opposing Weather teams (Sand, Rain, and even Hail).3 Ice type weaknesses leaves 1/2 of the team open to priority Ice Shard. Also, the collective offensive movepool of the team struggles against opposing Fire types, most specifically Heatran.
The Twin Tusk/Armor Pokemon's main staple in Ice Shard can nail 1/2 of the current team for SE damage despite all of the Chlorophyll abuse.
The current team struggles against Flash Fire Heatran greatly, as it's Typing paired with it's Ability allows it to completely wall the whole damn team. We're gonna fix that.
Naruto (Ninetales) @ Leftovers
EVs: 252 HP / 4 Def / 8 SAtk / 240 SDef / 4 Spd
- Sunny Day
- Fire Blast
This is the best Ninetails set IMO. The previous set was Switch-in bait for opposing Weather-setters with Solarbeam, which would have it's power halved while Ninetails is prey to a KO or Set-foddering as it charges up. This set cripples Physical Tyranitar with Will-o-Wisp, counter opposing Weather-setters switch-ins with Sunny Day. Able to beat Politoed one on one. Fire Blast over Flamethrower as to make up for it's lack of power.
Heatranny (Heatran) @ Air Balloon/Leftovers
Trait: Flash Fire
EVs: 252 SDef / 252 HP / 4 SAtk
- Stealth Rock
- Earth Power
- Lava Plume
Only suggestion here is to drop Toxic and replace it with Roar to prevent Set-Ups.
DinoPlant (Venusaur) @ Life Orb
EVs: 252 Spd / 252 SAtk / 4 HP
- Giga Drain
- Sludge Bomb
- Hidden Power [Ground]
The previous and suggested set are bothed walled by Heatran, so replace the Inaccurate Sleep Powder with HP Ground. Equip the Life Orb so you can abuse the extra power while restoring health with STAB Giga Drain.
Rotom-W < Jumpluff
Rotom-W @ Leftovers
EVs: 252 HP / 4 Def / 252 SAtk
Modest Nature (+SAtk, -Atk)
- Volt Switch
- Hydro Pump
- Pain Split
- Sunny Day
Jumpluff is dead weight. The Cottonweed Pokemon relies heavily on Sunny weather for it to work, and isn't a very potent Physical Sweeper (besides, you already have a Physical Sweeper). Thus, he should be replaced with a Pokemon that combats both Rain and Sand teams alike, Rotom-W. It's typing allows it to switch into several threats to the team such as Mamoswine. and gives the team an additional way to set up Sunny Weather which is guaranteed due to the surprise factor.
Sawsbuck < Leafeon
Sawsbuck (F) @ Choice Band
EVs: 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Horn Leech
- Jump Kick
Although Leafeon outspeeds Sawsbuck, the Season Pokemon is still capable of outspeeding a +Spd Venusaur while still running an Adamant Nature. It also has a form of recovery in it's Signature Move Horn Leech. The Doubled Speed from Chlorophyll and Doubled Attack from the Choice Band means that you have an absolute monster under the Sun.
. I would suggest a Hazard setter, but the team has no room for one of them. Hope I helped Zhengar, and once again, welcome to the site.