This is my first summer season riding this bike and I have noticed a sluggish throttle response when the engine gets hot. When the bike starts to run hot, oil temp around 250+ degrees and outside temps around 80 degrees, my throttle seems to get less responsive. It feels as if there is a lack of fuel or maybe just the opposite, a rich mixture but the engine really lags only when trying to start rolling from a stopped position; no other time. When engine is cooler, 150 - 200 degrees, it feels "normal". But please don't tell me to get the Dobeck EFI device. I went that route already. I would rather get the engine running properly without any add-ons. Any ideas what's going on? What to look for? What to do?