Ok. I've followed this thread since it started. Warrior, I really think something is hanging up at the brake caliper or something is broken inside. Maybe the stop bolt broke off inside. That's the bolt that is in the middle on the bottom. I think you need to pull it apart before you break sonething else. There's really nothing that should stop it like you're describing.

 

well, I thought it was the brake caliper cause I felt the impact of the blockage each time I would go back and forward with the chain adjuster. It really felt like the caliper was hitting something but I took the caliper off and it was still getting stopped. How do I go about disassembling the rear?

Btw, where can I go to get cheap wheel bearings for the wrong wheels?? Also, im guessing I will need a new bearing for the rear?

 

there should be a bolt facing down and rearward that you loosen. if its not it then its probably just rusted tight. lay the wd40 to and rock it back and forth till its comes loose. yoiu may even have to put a screw driver in between where the tensioners go and spread it a little. just be careful if you pry on the grooves on the left side too hard they will break.

 

to find some cheap wheel bearings check out rockymountainatv.com or motosport.com. they are both competitively priced. both front or rear from that site. you need to get the lock nuts off the rear axle. my advice is to go to a bond auto or something of that equivalent and find the book for complete tear down and rebuild of the 300ex. i really think that your 300ex wont adjust the chain because the carrier is dry inside and once you get it all apart put some grease right to it not WD40 because it will just fling off. i really really think once you get it apart and put it back together you will be able to adjust your chain by hand for a while.

 

ok, well i already tried prying the two pinch tensioners awhile ago. Ill try it again tomorrow. If that doesnt work, ill try disassembling it. Ill keep you posted, ill probably be doing this tomorrow night/sat morning. Maybe I would be able to better understand the problem if I could understand how the assembly works. I really cant figure out how turning that thing (if i could get it to turn) will somehow tighten the chain? Bear with me guys, im a bike guy.

 

Keep me posted Warrior. And turning it tightens the chain because the axle is not in the center of the thing that turns.

 

I’d imagine by now this was taken care of. I felt the need to post on this though for any future person that comes across this issue. This was the first search result I got when trying to Google for answers. The clanking noise is the caliper mounting bracket moving back and fourth. This is because the mounting bracket is froze onto the carrier bearing housing.(This is what’s stopping that adjuster from moving) To fix this, I started by taking off the rear brake caliper, removing both pinch bolts, pried the pinch apart a little bit, and removed the bottom bolt on the swing arm. Then behind your brake disc there is a snap ring keeping the caliper bracket from moving, you’re going to have to be patient and fit your tool between the spaces of the brake disc to remove the snap ring. (You could also unbolt the brake disc and move it aside to possibly make it easier). After the snap ring is removed, you can use a rubber mallet to smack the mounting bracket out of the swing arm housing and off of the end of the carrier bearing (where it’s stuck most likely) keep in mind, there’s only a few cms of room for the bracket to move between the swing arm housing and the disc brake hub. (It will not be able to come off completely) That little amount of room might be enough to break the mount free from the carrier bearing housing. In my experience I smacked the bracket back and fourth toward the swing arm and away from it, along with a lot of WD-40 eventually it came free, which allowed my chain adjuster to move freely once again. Huge PITA but it works if you don’t wanna have to take the rear entirely apart. Taking the carrier bearing housing out and removing the axle nut/brake hub/ and that mounting bracket out would also fix the issue if you don’t mind tearing the swingarm apart, personally did not wanna deal with that.