help with tires?

My friends KQ 300 starts fine and runs, as soon as you put it in gear and try to accelerate its bucks and farts like crazy, not moving... I cleaned carb and it worked good for 1 day... now back to same problem.... could it be such as a bent valve????

Have a 1998 AC 300 2x4, Just installed a new carburetor. Engine starts easy but the choke RPMs are very hi and take along time (5-10 mins when cold out). After engine has warmed up choke releases and it idles and runs fine., It does no have an electric choke. The choke lever is never used and it seems like an auto choke? Long story short, how can I lower the choke rpm levels?
 
Also, carb came with a spare145 jet, not 100% sure what is installed. Could this impact choke RPMs?
 
 
Any help and information greatly appreciated.

Bucking started about a month ago and works ok after 1/2 hour warmup.  Today while working on it i discovered that if i put the ignition switch in LIGHT position it runs fine right from the start.
I'm stumped!  Any idea why this could be?  

Hello I’m new here and was wondering is anyone knew of good replacement part numbers for front struts and rear shocks for this atv? I think I’ve found a new rear shock, that looks like the original but there is no dimensions or anything and was wondering if there are any afterMarket new front struts available. I know it’s a long shot but any help would be appreciated. 

This is something I'm extremely curious about. Has anyone ever attempted to buy a quad (or any other vehicle) from an impound lot? I've always wondered if this could be a bargain, or a waste of time. Google searches do turn up some helpful results. Looks like the state of NJ holds auctions online which I'd be a bit hesitant about.
 
My online searches haven't really turned up any results of anyone buying an ATV this way. I'd be really curious if anyone tried this, or knows someone who has. I've actually found a couple pages with online auctions for my state, but none had ATVs.