The stock hawk 250 carburetor comes with tamperproof screws. You can't unscrew it without doing some DIY modifications. It's fairly easy to do and the stock jets that come with the carburetor are not setup for top speed. This is one of the first upgrades you can should do on the hawk 250. You can buy a brand new carburetor without the tamperproof screws if you don't want to mess with the stock one.
Here is the the brand new carburetor with jets pack

VM26 Carburetor for Mikuni PZ30 Apollo Taotao 150cc 160cc 200cc 250cc Hawk 250 Pit Dirt Bike with 45mm Air Filter Mainfold Intake Pipe Fits Go-Kart SunL JCL ATV Motorbike
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Product Review Score
4.12 out of 5 stars
128 reviewsProduct links
Here is the jets pack if you want to modify the stock hawk 250 carb

Carburetor Jet Kit - VM22, VM24, VM26, VM30 Kit Replacement - Rejet Kit Compatible with 125, 150, 200, 250cc Dirt Pit Bike - 10-Pack with 88, 90, 95, 98, 100, 105, 110, 115, 120 & 125
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$12.99
Product Review Score
4.42 out of 5 stars
133 reviewsProduct links
You will need to remove the carburetor from your hawk 250 to replace the jets. The images below will show how I used a mini hax saw to modify the tamper proof screws so I can access the jets to replace them. If you have one of those dremels then this will be a lot easier.
The images above will show you where the jets are screwed in. There are 2 different jets inside of the carburetor. The carburetor will need a yearly cleaning so its a good idea to learn how to take the carb apart so it can be cleaned. If old gas sits inside of the carb then jelly will start growing in the carb and it won't start.
If you would like to see all the hawk 250 upgrades you can do on your bike. Click the image below to visit our hawk 250 parts & upgrades.