so far I got no complaints, my bike runs like a champ. Anyways good luck in getting yours dialed in, hopefully my parts will come in today, so I can get mine back together!

 

I bought a 2005 yfz450 3 weeks ago. Ive been riding it stock till i get around to putting after market parts on it. (quad cost to much) about 4 hrs later, alternater, and a clutch kill switch went bad. got repaired, 20 mins after gettting the quad back, same stuff goes wrong. another switch. It made mine die right off idle (pull clutch in it would die). not saying its the same thing . i dont know what yours is acting like. Make sure you get an extended warenty if anyones is buying new from yamaha.

 

na i fixed my problem.. that sounds like you got a bad one or something yamaha is one of the most reliable engines on the market today...