Ok, this is going to sound really sad but it was my first off road bike and I have found reason not to trust the dealer I bought the bike from.... I bought a used yz400F and it had a WR gas tank and seat. IT WAS sold to me as a YZ and I have been trying to get it set back up as a YZ. I bought a new tank and have ordered a new seat but it has been hell finding the parts. I had assumed that the prev. owner set it up with a WR tank and seat for trail rides but with as much trouble as I have been having finding parts I wondered why the guy would go that route as apposed to using an IMS tank and the existing YZ seat. I am wondering if I did not get sold a WR in disguise.. The fenders are YZ for sure, there is no throttle stop as on the WR's but alas I want to be sure what I was sold is what I bought.. Does anyone know how to check this out? Is there somewhere I can run the serial number to find out??? I had a ton of motor work done and they spec-ed it to a yz but if its a WR there could be problems... It does not ride like it has the wide ratio transmisson in it as the gears are really tight but it does have a 51 tooth rear on it that could make up some of that difference. Any advice or tips here?