General WR Question regarding 250/400 carbs

I have owned 2 WR400's, a 99 and a 2000 (still have the 99), and I am going to buy my son a 2006 WR250 tomorrow as part of his graduation, and to also get him off the 250 2T that plagues his riding ability (He bought it one day, coming home with it, not me).  Too much power, too unforgiving for him.  The 4T will hopefully remedy that, as he loves the smooth power of my 400, but I want him on a slightly smaller 4T bike (hence the 250F) to help him drill in the basics of solid woods riding here in New England.  Smooth is fast up here.


My question is this.  Over at the 250 forum, the information about mods to the carb does not appear to be as plentiful as what I have found here.  Are a lot of the tricks and tips I have used to get my 400 spot on the same in the 250 carb (I believe it is the MX variant in the 2006 model year)?


I have boxes of extra parts for my 400, and that is part of the reason I am buying the 06 before the 07 changed the frame, etc.  Right?


The new bike runs well, is my buddies old bike to boot, so I know he hasn't thrashed it.  I am a tinkerer, and will want to get the new 250 dialed in.  Is the AP diaphragm and linkage mode still the same in the 06 vintage for a 250F?  I already have the tokyo mods spring, extra OEM needles and leak jets too.


Thanks for the input in advance.

Edited by Phat Twin


I don't understand the part about getting a 06 before Yamaha changed the frame in 07. Are you thinking the 06 steel 250 frame is the same as your 400? They aren't other than the paint

It's my opinion that 250 2t with a flywheel would make a great off road machine . If you want to tame the hit you can also put the slow thurn cam in a G2 throttle along with a FW weight

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