help guys, one of my 250cc chinese atv rear chain slips off rear sprocket when riding....i can slip chain on sprocket only to have it slip off again...should i replace sprocket or take links out of chain or grease rear chain and sprocket and hope that stops slipping....oh yeh...where do i find rear sprockets for chinese 250cc atv. thanks

 

to check to see if you need new spockets grab a hold of the chain at the back of the rear spocket and pull it should only pull away from the rear spocket .10-.20 if it pulls away more you need to replace the spockets. if the chain doesn't pull away from the spockets then their's a alignment problem and it's not a spocket problem.

 

it appears chain extend about 1 inch behind sprocket when pulled....how does that translate to .10 or .20, if it does need alignment, how is that done and where is the first place to look to make the adjustment. i can put the chain on the sprocket only to have it pop off when give gas. thanks

 

Set the quad on a large block of wood, under the rear end skid plate - so that the rear wheels are not touching. Loosen the two large clamping bolts that are all the way back on the bearing housing. They should be about 4" long and kind of standing straight up an down. Loosen the brake caliper bracket to rear housing clamping bolt - about 3" long.

The axle sits "off center" in the aluminum bearing housing. You rotate the aluminum bearing housing within the steel rear "arm". BE CAREFUL of the aluminum housing - do not force it to rotate !!! Watch out for the "Greese Fitting" and "Alignment?? Plug" - they break off easily if you rotate them too far forward and they hit the front edge of the steel rear arm. You should be able to "wiggle" the aluminum carrier around be hand - if necessary you can stick a large screw driver into the rear gear to help rotate the bearing carrier. I think that by turning the grease fitting down and forward - this loosens the chain. By turning the grease fitting back and up - this tightens the chain (I could have it backwards - going from memory). Retighten two large 4" bolts. Set rear caliper where it should go and retighten the caliper 3" clamp bolt, and you should be good to go.
I like your use of the cap screws on the gear retainer ring - I just remembered that the chain interfered with something.

 

<div class="FTQUOTE"><begin quote>Originally posted by: bimmerman

it appears chain extend about 1 inch behind sprocket when pulled....how does that translate to .10 or .20, if it does need alignment, how is that done and where is the first place to look to make the adjustment. i can put the chain on the sprocket only to have it pop off when give gas. thanks</end quote></div>

if indeed you can pull the chain away 1" from the back of the rear spocket, it's no aligment problem. it time for a front and rear spockets with a new chain.

 

<div class="FTQUOTE"><begin quote>Originally posted by: bimmerman

it appears chain extend about 1 inch behind sprocket when pulled....how does that translate to .10 or .20, </end quote></div>

That would be 1.00 about 10 times to much wear. Seems like a LOT of wear to not break. Have you ever tightened the chain bimmerman? I would guess its way too loose.

 

Bimmerman,
What model or brand is the ATV ? Does your's have a chain tensioner ? The factory chain on my Taotao 250 D kept stretching and falling off the first week we had it, so I replaced the chain with a 428H heavy duty KMC chain and that fixed the problem and has not fell off since.

Slydog

 

thanks guys, i think i've found the problem....missing chasis bolt and loose bolt in close location to chain and sprocket....chain probably coming off due to instability of axle? what do you think?....after 3 months of riding by sons really have not had any serious problems with chinese atvs....now is the time to do a all over bolt check and tighten...

 

bought 2 atvs from t-motorsports (chino, california), 250cc E,water-cooled w/reverse...does not say the brand...will check for tensioner...i think so....yes i am very new to the sport and learning as i go along...thanks

 

Any loose bolts related to keeping the chain tight will of course cause the chain to fall off, so yes re-tighten and see if that helps. You never did say what model ATV you have ?

Slydog