If you are having the same 4th gear problem here is a somewhat easy way to test to see if you have the same problem. The good news is you can test this without buying parts, save gaskets and seals if you mess yours up (I used the originals and have no leaks). The bad news is your going to have to dis-assemble a lot of stuff to do the test...about an hours worth. You can follow the instructions way back at the beginning of this section to get the bike down to the shifting components. Once you have done that take out the center retainer (5mm Allen bolt) and pull the shift cam plate, shifting star and shifter shaft out and set them aside. Take the nut off the Stopper Comp assembly (if it comes off) and unhook the spring from the Stopper Comp arm. Put the nut back on and tighten to spec (7.0 ft-lb) and see if the Stopper Comp arm will move freely. If the nut doesn't come off, but rather the entire stud comes out like mine did you can still do the same test. Remove the spring from the Stopper Comp arm, re-tighten to spec and see if the arm moves freely. If it does, then you got another problem and may need to order the parts previously mentioned. If the Stopper Comp arm does not float freely then you have the same problem I did. Take the assembly back apart and using a file or grinder (carefully) remove a small (think 100ths of an inch) amount off the side of the Stopper Comp arm, and do a test fit again, if the arm still does not move freely repeat the same procedure until it does. You should not have to take off more than just a few 100ths of an inch to make the arm move freely. Once the assembled Stopper Comp arm moves freely re-assemble and see if that fixes your problem and drop me an email and let me know if it did or didn't fix the problem for you. If you want to order any of the parts related to the Stopper Comp assembly here is a diagram with the part numbers and prices available from RonAyers.com. The only reason I listed RonAyers is because they were significantly cheaper than anyone else that I got quotes from and I have ordered a lot of parts from them without an issue. Happy Ridin'.