Throwing chain... HELP! have a race in a few days

[BS300ex5]

hey i have a 300ex and it seems when i'm riding through woods or anywhere for that matter and i tourque on the gas some it throws a chain... the chain can be tight and work it's way loose in a matter of a half hour of riding... what can i look for to be worn? the chain doesn't look to be worn or stretched and the sprockets are good... and it lines up...

[canadian400ex]

check your 4 allen head bolts at the back of your swing-arm. They may be stripped.

[BS300ex5]

the bolts go down to tight...they aren't stripped...

[KY Woods Rider]

Check the axle bearings, but if the sprockets are lined up okay that's probably not the cause.

Have you ever noticed if it seems like the carrier is slipping forward and loosening the chain? Sometimes you can get a build-up of dirt stuffed between the swingarm and carrier and even if the bolts are tight, the dirt and grime doesn't let the swingarm hold the carrier tight enough, so the carrier starts turning forward and loosens the chain.

[plkmonster2]

Use a sharpie, and mark on both the carrier, and the swingarm. These will be your reference marks. If they get out of whack, then your carrier is turning.

[markk]

Originally posted by canadian400ex
check your 4 allen head bolts at the back of your swing-arm. They may be stripped.


I think the 300exs only have two bolts right?? I would mabey try to pull your carrier out and make sure everything looks good on it, and mabey it was slide in upside down (if that makes any sence to you) Iono i had that problem with my quad at the Wisp! good luck man!

[kicken250x]

it sounds to me like your rubber pieces that hold the carrier in or the bearings are shot. the loosening of the chain comming from the 2 rubber pieces that go in the slots cut in the swing arm because those 2 bolts alone cannot hold the carrier in place, believe me i know... and i say your bearings could possibly be shot because your chain is comming off. if they are gone or going then this will allow your sprockets to come out of line and will force the chain off the rear sprocket. i hope this helps. if you have anymore questions just ask. later


and a 300ex does only have 2 bolts, one on each side, its the 400 that has 4

[Jingle 11]

yup even if all of ur crap is tightend and ur carrier is shot ur chain will still come loose. ive replaced 2 carriers in my old 300 and 1 in my 400. i know my shat. i bet ur bearings are going out or ur carrier is crap.