i have been having a problem with my atv breaking chains lately... i have broken my brand new chain twice in the past week... it was repaired the first time with a new part, but it has recently broken again, this time cracking the case, and left side ignition cover.... i've got that part covered, but i really don't know why it is breaking chains. the chain has a lot of slack in it, but i'm not able to take out another link, and my sprockets are in perfect condition... so, i really need to know why this is happening, i have a feeling that the swingarm bushing could be bad, but i don't feel any play in the swingarm. any help is greatly appreciated..thank you in advance for all helping posts.

 

make sure that you are using the right type of chain, and that the slack is adjusted properly, too much slack might cause a problem. try buying a stronger chain and make sure that the masterlink clip is facing the right way.

 

Wow, sounds like you have done a great job in checking things that cause this type of thing. Some other things you should check.

Motor mounts or frame for cracks or loose bolts
End play on the motor sprocket
Side play on the swingarm (check again)

If you have a lot of slack in the chain, this can cause the problem. Why all the slack? Anytime you have slack in something, chain, belts, gears or whatever, it can over load the tensile strength of the part. Why can't you take another link out?

I can only assume your buying a good chain?

 

try adjusting and rear axil to get that slack out if u cant take another link out

 

thanx Doctorturbo, for the advice. i have no clue why the chain has so much slack, but the reason i can't take another link out is that the chain will be slightly too short if i do this. i was thinking about a chain tensioner... would this help with this problem... i'll check the swingarm bushings tomorrow, by taking the swingarm off, and see if that is the problem. the rear axle bearings had to be replaced only about a month agao, which i did myself, but i'm wondering if that when the axle had all the play in it from the axle bearing going(going= totally destroyed bearing, some ball bearings were pulverised, the others were loose in the carrier) if it could have ruined the bushings in the swingarm?? BTW, i used a DID 520 chain, which is brand new.

 

replace both sprockets and chain

 

Bing may be on to something. A bad sprocket could cause slippage.

Also, try using a half link. I'll bet you are way too loose on the slack

 

If you can't remove one linl without the chain being too tight and you can't adjust the chain tension correctly the way it is something is VERY wrong. Since you blew your bearings apart so badly did you inspect the axle/beating carrier carefully? I know you check swingarm play but did you inspect axle play? You may have damaged your axle/bearing carrier or even you axle. Check for play. Also check to make sure your sprokects are in line with each other. Is your axle in all the way? Misalighnment of the sprockets would break a chain very quickly.

 

are all the teeth on your sprocket still there

 

i took off the swingarm assembly today to make sure that the bearings were ok, and i got my answer to why it is breaking chains... the swingarm pivot bearings were virtually gone, and in many pieces, so replacing these will most likely fix the whole problem. thanx again for all of your help! oh, and by the way, i said that my sprockets are in perfect condition, and there is no axle play. the axle is in good condition( those durablue axles hold up well) even though what happened to those old bearings a month ago.