What engines will fit in a 2003 frame?

Hey TT, I'm new here, I searched the FAQ's and dint find an answer, plus I'm on a dinky smart phone, and some functions don't work, namely the search function. But, my question inquiry is about a 2003 yz450. I want to make it a street legal motard, since I live on the tail of the dragon us129. Finding an eline stator will take too long, and I'm not opposed to doing the left side swap for the wr stator, but if I were to have acces to a wr450 engine, would it just bolt up to the frame? I'd try to find an '06 and up so I'd have a 5spd tranny, but are there mounting issues with the frame mount locations?

Thanks for any help.

First, there is no bolt on swap for the use of the '03-'06 WR flywheel/stator for the '03-'05 YZ450.  That job requires the crank and crankcases from the WR, along with another pile of parts.  Your best bet is a used WR engine from '03-'06, and that will also get you the 5 speed.


The '06+ YZ450 or '07+ WR engines can be bolted in, but they have a lot of clearance issues around the carb and top end because those engines stand more upright in the frame.  I would not recommend that you attempt that.

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