Hi. Had an issue with the drz this weekend. Both times in the dirt. Bike would shift to third gear and come back down again but then when I try to go back up it won't go past 3rd. Put in to neutral rolled it back and started again and got it going. Wondered if I somehow imagined it.... Next day had the same problem. Went up and down a few times and eventually unjammed and went again. Oil is clean and plenty in there..... Any suggestions?