Ive got a 2000 sv650 that had similar problems. Check your Regulator Rectifier and your battery. I would replace your battery if its the stock one. by replacing the battery in my sv that fixed i also replaced my Regulator Rectifier as well a while later due to charging problems but the battery alone fixed the starting up problem. If you have another bike or a friend willing to come let you borrow there battery that’s what I did. I took my battery out of my gsxr and put it in the sv and the sv battery was in my gsxr, everything worked fine my gsxr was struggling to start up after sitting for more then an hour after riding it for more than 30 minutes more than enough time to charge the battery well.