It's a 2000 Alpha sport 90cc atv.

It has been good except for the carb, seems there are always issues with it. Most of the time it is too lean. It is tough to start when cold and seems tempermental.

Either the stock jetting was changed before I got it or it's junk.
I have taken it apart cleaned it and spent hours trying to adjust it.

I just did a quck look on ebay and saw carbs as low as $29.

Is there a descent replacement carb? Any recommendations?

It has a mikuni carb on it now.

 

Well my friend, it look slike you have a problem. Not sure a replacement is going to solve the problem. Let me fill you in on what you should be doing EVERY time you run the quad. 1) use fresh gas religously. 2) Always rock the machine back and forth to mix the ethanol and gas again because if it sits, it will seperate. 3) every time you ride, while the motor is running, turn off the gas and let it run all the gas from the float bowl and the engine dies.
Do these and it will eliminate a lot of isues with small bore carbs. Once you have a problem though, the best advice I can give you is to find a good carb shop that uses an ultrasonic cleaning tank. everything else is a waste of time.

 

I had made some progress. I took thae carb apart and soaked it overnight this time.
I got it together and got it running but it wasn't easy.

I had to spray gas/oil mix into the carb, kick it over repeat. It eventually warmed up enough to run.

I have come to the conclusion that the electric choke is not working properly. Converting to manual would probably fix the issue.

However, it was making a noise when it was running. Almost like a bearing was going. Not sure I went to spend $65 on the manual choke if something is going to go.