Looking at the tech specs the 83/84 250 wr & XC are very close. Both use the wr tranny, primary gearing, final gearing, the wr uses the SEM IGNITION and the XC uses the MOTOPLAT IGNITION. I'm thinking the XC used the cr cylinder. The XC suspension has about 2" more travel I guess that's the cr suspension. I'm just trying to figure out the differences between the wr and XC. I got into this because my 84 250wr has no markings. The key find is the SEM ignition so she's a wr model.