I have a 07 CR250R that I use as a back up for my CRF450 so I don't ride it that often. In the past year it's been ridden less than 10 times. Since my last ride in January the rear tire started to leak so I filled it with 25 lbs and it went down to 0 in 2 days. I started to replace the tube yesterday and noticed some dirt inside the tire. I've seen this before especially after a crash where the side wall flexed but this time there was no crash to cause it. By the time I got the bead removed I saw about 1-2 lbs of dirt inside the tire. I ended up having to clean the rim lock, the rim band and the rim, scrubbing the spoke nipples so they won't seize, for over an hour. The tire had dirt crusted around the inside so I had to pound it on my driveway to break it free and then vacuum the debris out of the tire. Has anyone else had an experience like this?