Dropped my zzr250 for the first time on the weekend, back wheel got stuck in something doing a very low speed u turn on a slight very dark hill. Bike was running when it fell and turned off before i picked it up. Took me ages to start and then when i did i reved the shit out of it for a little bit then took off (i heard this was to get rid of shit that could of built up but this might be wrong). I rode it to a mates place 5km away then parked it for the night. Rode it home the next day. Now when I start it, it idles lots lower in all circumstances ie with no choke on it's less then 1000 (And struggles not to stall) used to be high 1000's. With full choke it's only like 3-4k not 5-6k. My friend said it might be firing on one cylinder? Is this true? How do i fix it? If not what's wrong? It had a major service with all new oils, fluids etc. around end of june/start of july and i've only put 200km on it since then.