Chain & Sprocket Diagnosis?

[quadman21]

Ok, I'm gonna try to make this as short as possible. My chain de-railed at a XC race this past weekend. I just need some feed back on what causes a chain to de-rail? This has never happened before so I am somewhat at a loss trying to determine exactly what caused it so I can fix the issue. btw I run a lonestar sprocket guard

[brian 68]

was your chain lose? if not sometimes something, (rock, log) will rub against it, or get wedged between the chain and sprocket and derail it. as long as it isn't happening alot don't worry, sh#t happens

[Jim417mx]

Main cause is a loose chain... other than that, look for:

-worn down sprockets
-worn down chain
-loose sprocket /sprocket hub
-play in the axle carrier bearings would angle the sprocket so the chain would not ride on it the right way, causing it to slip off.
-play in the swingarm pivot bearings causing the swingarm to move left/right a little bit, causing the chain to slip off, but this is kinda rare, happens more on quads that have front sprockets with the giant nut instead of the 2 10mm bolts that hold them on.
-loose axle nut, causing slight play in the sprocket hub


Or like mentioned above you could have just ran into a rock or something and it just knocked the chain off.

[mikecancu812]

I second all the above. I had the same problem on an older quad and it was the swingarm bearings wore out wobblin back end. Doesn't take much movement side to side to throw one