Motor options/swap in 2003 wr450....

I just picked up a nj street legal wr450 that was locked up. Most likely going to need a crank jug and piston, but I was wondering if anyone has an info on direct drop in motors or one that will fit without a crazy amount of fabrication. For the price I paid it's worth using as a roller, I have an 02yz250 also and was curious if that might fit, or if anyone knows of any others that could fit, 2 or 4 stroke. Nj is hard to get street legal dirt bikes but there is no inspection so nobody will know what motor should or shouldn't be in it as long as the reg matches the vin and I have a plate on it. Thanks for any input.

2003-2006 wr motor will fit

Was looking for other than wr450 options.

Anything else is not going to be a direct drop in. I would rebuild the WR engine, it's going to cost but likely cheaper in the long run versus a Frankenstein engine swap where nothing lines up.

Unless you put in a KX or CR500, that chassis is going to be too heavy...

Anything else is not going to be a direct drop in. I would rebuild the WR engine, it's going to cost but likely cheaper in the long run versus a Frankenstein engine swap where nothing lines up.

only thing I would have an issue with is the bolt thru the swingarm and case. cr500 motor would be my first pick, but finding a motor is hard

I'm all for dropping a CR500 motor in just about anything but I cant see what you would be gaining.

You would probley have to buy a complete old steelie CR500 just for the motor. A well set up, properly suspended old (96-01) steelie fame 500 will do everything better than your 03 WR conversion. Other than looking dated.

Your best bet is to just rebuild the motor ya got. Then you know exactly what you have when your all done.

Plus I don't think putting a smaller lighter 2 stroke engine in a 03 WR frame is going to make the bike handle any better. Which is the only thing about my 03 WR I've never been happy with.

Edited by adam500

I'm all for dropping a CR500 motor in just about anything but I cant see what you would be gaining.

You would probley have to buy a complete old steelie CR500 just for the motor. A well set up, properly suspended old (96-01) steelie fame 500 will do everything better than your 03 WR conversion. Other than looking dated.

Your best bet is to just rebuild the motor ya got. Then you know exactly what you have when your all done.

Plus I don't think putting a smaller lighter 2 stroke engine in a 03 WR frame is going to make the bike handle any better. Which is the only thing about my 03 WR I've never been happy with.

My thoughts exactly. And if it's rebuilt properly, the WR engine is a reliable and low maintenance power plant.

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