the bike is an 03 wr450, mechanically stock. no engine mods and stock pipe. only mods are a Baja designs street legal kit.
took the carb to a Yamaha dealer to have them use the ultrasonic cleaner on it and have the guy who's owned multiple WR's re-jet it to make it work like our 07 w/ AIS removal.
the 07 is easer to start cold mornings and runs a fair bit cooler on tight trails. figured it was lean jetting like one reads all over the internet.
phoned them today and it's ready, the tech there said that the carb did have some gunk in it, and the stock jetting should be fine for a stock bike????? I've read all over the place about these things being wrong from the factory.
I'm not convinced that cleaning was enough... is it possible for a somewhat gunked up carb to cause a certain amount of a lean condition and cause these symptoms? so cleaning it and engine ice should help it out a lot? or does this tech not know his stuff?
the bike runs great and had a few hundred miles on this year since we bought er'. just gets real hot on tight trails (feels stupid hot on legs but never reached boil-over) and is a real pain to get going on a cold morning and needs a ton of choke before it'll idle cold no matter the outside temp; where the 07 isn't much warmer then my old TT-R 225 in the tight trails and fires up pretty easy no matter the temp and only needs a few seconds of choke.
we bought both bikes the way they are now but the 03 did sit around for a little while and the owner of the 07 seemed like a pretty serious rider who took good care of stuff. so I believe there being some crap in the carb of the 03 but research shows they all needed different jetting.
thanks in advance just trying to arm myself with the info for when I go pick this up and talk to this tech in person.
Edited by essonlaker, January 15, 2015 - 05:35 PM.