Got a few questions for yall. I'm a good diy'er, but know nothing about carbs. and new to atv's in general. I got my son a 125 Coolster for his birthday last year. And before yall start, I know. I should have got a Honda. I was short on money, it was his birthday and I wasn't sure he would use it. Plus he'll outgrow it. A year later exactly and he still don't ride much, rather play video games and watch youtube. Anyway. ....

The Coolster has been a decent atv for what it is and what use it'll see with my son and younger daughters around our land. I just ordered new sprockets 12t front and 48 rear and a better chain for the new application. Trying to get better low end power. It's plenty fast, but weak. Mostly due to the automatic gearing. Seems like it's always in 2nd or 3rd gear. Figured sprockets would help some.

As you'd expect, the carb is junk on these things. You can only adjust 1 screw. The rest are sealed. I'm not sure what this one screw adjusts, but it'll change the idle. When you accelerate( full throttle from a stop), it'll bog down. Figured it was a carb issue

The carb is a pz20. I'm not sure what pz is. If it's a brand, type or size. Hopefully someone can tell me. I'm guessing the 20 is for 20mm. Can I upgrade and get a 22mm and bigger just by swapping carbs, or will I need to change everything?

What are some other upgrades I can give this little Chinese quad more power? I want to keep the speed, but willing to sacrifice a little for more hill climbing and trail riding. I've read about sprockets, cdi, carbs, etc. Just not sure where to start with the carb sizes and models.

Thanks in advance

 

Did you ever get anywhere with that carb question..i was wondering the same..my little 125cc coolster has 1 screw on carb as well..its an idle screw..thing is always stalling..my daughter has a hard time riding a trail for 5 minutes before it stalls..also will sometimes die while idling..idle is not stable at all..it will rev up on its own and if i dont go and tap the throttle a little bit it will idle high sometimes it will come back down on its own...ive cleaned out carb by blowing air through it..you cant even remove the bowl from carb as its sealed..you cant really access the jets..just blow air through it or try to atleast..yeah im lost as of now..

 

I got this carb, also the xpro cdi and high performance coil. About $75.00 in parts and it will run nightb and day difference with no stalling and random dying.

https://www.powersportsmax.com/product_info.php/cPath/313/products_id/13021