twhaping sound when accelerating

I dont know if its something to do with kick stand or chain but when im in first gear and take off fast a loud thumping sound almost like chain is flopping around also kinda sound like the kickstand smacking up and down does anyone have any idea what may be causing this thanks

possibly chain tension. check and adjust if necessary. also could be worn center stand spring allowing the center stand to bounce. I hear my center stand bounce when i go over speed bumps.

Mine was chain tension, as i had already fixed the center stand that had been rubbing on the chain before I got the bike. If it has a center stand check the edge to see if its hitting at all.

how do i know if the chain needs tightening ? other than that sound

Get yourself a Factory Service Manual (not Hanes ar Clymer) if you don't have one already .......and look at the chapter on periodic maintenance, chain section, it will give you all the info you need.

Does your rear sprocket have any teeth left on it? Or just lumps.

Seen that more times than I can count.