2006 YZ450 / 2007 WR450 Engine Swap

I have an 06 450f that is set up really nice, suspension built for me, dampner, FMF Ti Pipe, its Street Legal & Plated. But my lighting is weak and poor with no real way to a high power electrical system and that keeps me from having nice lighting for night time off road rides. A high power stator, wide ratio trans and e-start will be nice to have.

I am trying to figure out without having to buy the engine cases if modern AL framed WR motor will fit in the 06 AL framed YZ.

Anyone tried ? Yamaha mechanics, are the bolt patterns the same ?

I am not worried about the labor expense as I will be doing the work myself and I assume I can part out the left overs of both motors to more than cove my costs.

Thoughts ?

The '07-'11 WR450F engine is a direct fit in the '06-'09 YZ450F chassis. Use the YZ carb and exhaust and also cams, if you want the power to stay as is. You WILL have to use a WR450 CDI unit with the WR electricals, or have a custom rewind job done on the WR stator to accommodate the YZ450 CDI.

Thanks just what I was looking for. Will report back once it is done.

One more thing guessing I need a subframe too, to do it right ... I assume that is a bolt ot or do I just weld in a battery tray ?

One more thing guessing I need a subframe too, to do it right ... I assume that is a bolt ot or do I just weld in a battery tray ?

One more thing guessing I need a subframe too, to do it right ... I assume that is a bolt ot or do I just weld in a battery tray ?

Subframe will not interchange without modification. Google image the two bikes in question and you will see on the left side where the sub frame mounts much higher up on the main frame on the yz than the wr. The wr sub frame has to clear the side access door on the airbox. I know this swap can work because I almost bought a similar conversion from someone who did this. He put the 07' wr in a 08' yz 250f frame and loved it. He felt like it was a very noticable improvement for cornering and such. There were slight frame changes on the 07' yz250f and 08' yz450f/250f that helped them handle better. He cut and rewelded the sub frame to line up with the yz frame but it didn't look very clean. You would probably be better off fitting the battery to the yz subrame.

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