Difficult cold start is symptomatic of the exhaust valve gap closing up over time.
I think the valve gap is .004 inches for both intake and exhaust, it's in the manual, and is relatively easy to do, once you get all the plastic off. There's videos on you tube on how to do it, open up the variator cover, put a wrench on the nut and turn the engine to top dead center, check the valves with a feeler gauge, et voila.
My 500r starts pretty easy after I adjusted it, but my 500ri left me stranded a few times because I don't think it has a heated element for the fuel injection, so if yours is fuel injected, that may be the problem. I just ride the carb model now, and it's fine in the cold.