Having to bump start the GS500 probably means it needs a new battery which might be causing the surging- some places might be able to test a motorcycle battery- but it is fewer places than for a larger car battery.
Heat kills batteries, so if you live in a desert or put 15,000 miles a year on your bike, the heat from the weather or the heat from the engine will kill the battery faster. I only ride my bike 2,500 miles a year and it is a low compression engine with about 35 horsepower, so my last battery lasted 6 years. I also ride at least every 3 weeks all winter, usually more often, and never go less than 10 miles after starting the engine. I rarely do city type riding stoplight to stoplight, which also heats up the battery more.