BAck Sprocket Fell off

4 replies to this topic
  • dirtbikebd

Posted October 22, 2001 - 06:56 AM


Saturday my buddy and I went riding. The first thing I check is the back sprocket, because I have lost a bolt before. Well my friend took my bike out on the track. I took his cr250. While he was going around the back sprocket fell off. Luckily he was riding because he is a better rider and if it was me, I probably would have got f'd up. Is this a problem that everyone else is having? AND the holes in the hub are starting to Oval, can this be a warranty issue?

On another note, I did do the BK mod, and definatley liked the snap coming out of the corners.

Also, after riding the 2-smoke, I may be going back to the 2 smoke. Much nicer ride for me, especially at 5'5".

  • BK14MX

Posted October 22, 2001 - 07:04 AM


Without knowing for sure, maybe sounds like your chain was too tight. I have seen a couple of hubs basically explode from this. Generally speaking a 2 stroke doesnt have enough "thump" to accomplish this, its very important to have the correct slack in a 4-bangers chain. Check the manual for exact measurements. Also, if your bolt holes in your hub are damaged, the hub is toast. Unless someone knows of a procedure to put inserts in to get the tolerences back to spec??? Good luck.

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  • dhowell

Posted October 22, 2001 - 08:10 AM


I had noticed the bolts on my sprocket would get loose from time to time. I took them out , applied a little lock tight and I have not had the problem since.

  • Jason_in_KC

Posted October 22, 2001 - 10:07 AM


I am lucky to have a veteran motoxer and off road rider that I get advice from. He helped me put a new sprocket on my bike earlier this year..I asked him how tight these bolts needed to be. We put red loc-tite on each one, tightened them down very tight by hand and then put a box-end wrench on them and give them two good hits w/the rubber mallet until they squeaked...and they will squeak! I haven't had them so much as move since April!! These sprocket bolts are notorious for being original sprocket bolts did come loose and ovaled out..scary stuff!

  • blbainb

Posted October 22, 2001 - 03:14 PM


I ran into this problem last year on the '01 and found that the free play specified in the manual is wrong. As long as you don't reduce the slack below 1.9" then you'll be fine. I found that the chain wears more slowly, as well.

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