WR450 Hybrid.

[rob-u/21]

Has anyone done WR450/400ex frame hybrid? I came across a 2003 WR450 engine at a very low cost so I'm thinking of getting at droping it in to my 400ex chassis since I don't have a motor for it. Does anyone know the performance differences between a YZF450 and a WR450 motor? I've read the YZF engines are the easiest to drop in a 400ex chassis does this go the same for WR motors? Any info will be apreciated. Thanks.

[usp4u]

WR engine mounting should be the same as YZ. Neither is simply a "drop-in", do some searches on here and you will find alot of info. What would this machine be used for ? Dont forget, a WR is NOT simply a YZ with 5th gear. If you were to MX it, you may find the gear spacing of the wide-ratio WR box to be awful in a quad...it not even very good on a track in a bike thats 150lbs. lighter. food for thought. might be great as a trail quad.

[rob-u/21]

Originally posted by usp4u
WR engine mounting should be the same as YZ. Neither is simply a "drop-in", do some searches on here and you will find alot of info. What would this machine be used for ? Dont forget, a WR is NOT simply a YZ with 5th gear. If you were to MX it, you may find the gear spacing of the wide-ratio WR box to be awful in a quad...it not even very good on a track in a bike thats 150lbs. lighter. food for thought. might be great as a trail quad.

Thanks for the quick reply. I understand it won't be as simple as droping it in. I have done a lot of searching and I said drop it in cause the YZF/YFZ engines seem to be the most suitable for an ex chassis. I've been wanting to build an MX quad out of my ex frame, but since I was offered this WR engine at such a good price I'm now thinking of building a desert quad with a WR/ex chassis combo. Do you think this motor would work well out in the baja desert? Thanks again.

[usp4u]

you could probably make a great desert bomber out of the WR mill. thats probably the best place for the wide-ratio tranny, in a quad. figure 20" tire and play with sproket selction a little, i'm sure it would work. if you choose to use it, do some reading over at Thumpertalk.com in the WR forum or read any old issue of Dirt Rider were they test a WR to figure out how to make the thing run properly, Yamaha really choked those things up and some simple, low cost mods can get them breathing again.

[Nevada520]

According to all the guys on this board ss440ex was making a very quality conversion kit to put the YZ engine in the EX frame. PM him and maybe he can give you more info on the details of the mods required and performance difference. I think he has a few things for sale rigtht now.