As stated, make sure the battery is fully charged.
Don't jump it off a car, make sure the battery is good.
It will sound like a can of rocks rolling around when it first starts up, this is NORMAL. They all sound like the bottom is going to jump out of them.
As to the choke, I'm in a colder area of the country, it's not
unusual to need full choke for a minute or 3.
then work it back keeping the revs in the 3000rpm range.
yes the side stands suck, they bend at the mount. Buy a center stand, it's cheaper than repairs. Or a side stand from a Trophy, they're heavier, beefier.
Check the tires 7K, rear is close to done, front about ready for replacement.
Ask about fluids, as in when were they done ?
Look at the obvious, chain, sprockets, rust in the tank.
Pull the seat and look under it, check the air nozzles for mouse droppings.
Don't jump to conclusions.
Know how seller is lying to you ?
His lips are moving
