Engine swap, xs250rk.

[Magua]

I'm looking at purchasing an xs250 as a project, it has a blown motor. The bike in question is an '86 XS250 RK, engine number 17E-105551. I've managed to find a replacement engine that looks to be in decent condition, althought it looks the same, the owner is not certain of the year or model of XS250 it came from. The Engine number on it is 19Y-000901.

Anyone here able to determine if it would fit from those engine numbers? If not, does anyone know of the development history of the xs? Was there a point where they changed the frame or engine?

Thanks in advance.

[Magua]

XS 250 RK 83 17E
XS 250 RK 83 19Y

That's about all the information I've been able to find.
http://www.dropbears.com/m/models/yamaha/modelcodes.htm

Looks to me as if they're one and the same.

[Magua]

Doh, the engine sold.

[xwhatsit]

Might I recommend a different project bike. One a little less portly and with a little more get-up-and-go -- I know you own a Superdream, but GN250s are significantly faster than an XS250

[Magua]

Significantly faster? lol. Must be terribly slow. It wasn't for me, but for my brother, trying to get him a bike. He's a rather portly fellow, so perhaps more power is the way to go.

[Bonez]

You can slip an XS400rk donk in .