I recently got the bike from my brother in law, it has been sitting for about 4 years, but was running perfect when parked. I flushed the gas tank and fuel line and refilled it with 93 octane, checked the spark plug and it looks fine, changed the oil, and replaced the air filter. It starts and idles fine, but doesn't have half the power it should, and will randomly die or at least try to, it will only go about 47 in high. Clutches seem to be moving fine, but I haven't completely ruled it out. I've read all kinds of different things to check, but it would be awesome if someone could give me a general direction to start troubleshooting.