Has anyone ever saw a 250x/300ex with a 400ex or YZF engine in it?????

Also, anyone have a pic of a 400ex engine sitting next to a 250x/300ex engine? Just tyring to get a feel for the difference in sizes.

Thanks!

 

The 400EX engine is smaller physically than the 250X,300EX, and 350X engines.

The 350X engine is almost a direct drop-in into the 250X/300EX quads. The 350X has only one less horsepower than the 400EX and has a 6 speed transmission. While it does weigh more, this would be the engine to drop into a 300EX.

The 400EX engine would require more work to fit than the 350X engine.

The 250X/300EX chassis wouldn't hold up through one race with an engine pumping the kind of power that comes from the Yamaha. That's my guess anyway.

 

How many HP does the Yamaha put out?

And do you know if the Yamaha is much larger than the 400ex or the 350X?

The 250X/300ex has been handling 50hp+ for years(thorugh top racers such as when Travis Spader ran one in the early 90's), so I think the chassis can handle just about anythign you throw at it.

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I have a line on a 350X for a decent price. I know Powroll makes a kit you can buy to bolt the 350X into the 250X chassis for $100, but can the mods be done by a creative and handy do-it- yourselfer?