Motorcycle Repair: sputterer, yamaha 650, petcock

Question
I have a yamaha 650 and it sat up for nearly a year, i have had the carb. cleaned and had to jump it of. when it does start it just kind of sputters, it runs a little better at half throttle but at full it just putters out. but does stay running at a putter


Answer
Is the bike starting via a kickstart or on the battery? What year and model is this?

It sounds like either the petcock is not supplying enough fuel or the carbs still have some dirt which is limiting the fuel supply at WOT.

A problem I've sometimes seen is that the petcock will supply enough to allow the bike to run fine most of the time. But go up a hill and the carbs drain out as they are sucking up gas faster than the petcock can supply it. The result is that the bike sputters for a while until the carbs fill up again. The problem can be the petcock or it can be the float valve on a particular carb.