I have a 95 YZF600 that won't idle. With the choke it won't idle lower than 1,500-2,000. Without the choke, it doesn't want to idle at all. It also runs rough below 4-5k rpm. The bike is stock, plugs are new, fuel level in carbs is good, jets are set up according to FSM. Also, if you rev it at idle, rpm fall down quickly. What else should I check? Should I just get used carbs off ebay to see if that helps?