the chain on my kids' 50cc yamoto has been coming off lately. it was obviously too loose so this weekend i tightened it. now i'm worried that it's too tight. i don't want the chain to break or the sprockets to wear out prematurely. it's got some play in it but not a lot. maybe 1/2" or so.

 

you need to make sure that there is some slack on it all the way through the suspension stroke/travel. meaning, at top of shock stroke, not too tight, and bottom of shock stroke, not too loose. wow, that's about as clear as mud.........1/2"-1" will be fine. just double check the slack at both ends of the shock travel. you can use people on the quad or a ratchet strap to compress the rearend to check it out........

 

i get what you're saying. i've only been checking it with with no one on it. thanks a lot.

 

With the rider on, chains should indeed have 1/2-1 inch of movement.

 

i may need to loosen it up just a hair then. it probably has 1/2-1" of play when no one's on it & when i sat on it this morning (150 lbs.) it still had probably 1/2" but it seemed sort of stiff. it wasn't so stiff that it wouldn't budge though. is it better to be a little on the tight side or a little on the loose side? what are the downsides of each?

 

you need to find a happy medium with the chain. too loose and of course it'll pop off of the sprocket, catch something and break. too tight is premature wear and stress on chain, sprocket, and bearings.......

 

ok, here's what's going on now. i had the chain tightened to what i thought was a good medium like you said but when i moved the 4 wheeler forward or backward i noticed that it would change depending on where the chain was in the rotation. not sure if that makes sense. what i'm saying is that the chain might feel fine. if i moved the 4 wheeler forward or backward a little it would change the feeling of the chain. moving it more would change it again. it also changes if i scoot the rear end of the 4 wheeler left or right. for instance, if i scoot it to the right the chain will feel nice & tight. if i scoot it back to the left it will feel much looser. all bolts are tightened & i'm stumped.

 

i'm not sure about yours, but mine will do pretty much the same thing after an adjustment. i just watch it to see if it needs more, but as long as it ain't slipping off or jumping teeth, i go with it. so far, no problems........you did check out the suspension travel when you adjusted it right?

 

Why is it moving right or left? Sounds like some bearings may be bad.

 

Put the quad frame on a block or jack stand so that the rear wheels are jacked up in the air. Grab the rear axle and try to move it left and right. Is anything loose or have lots of play? Look at the swing arm play at the swing arm bushing, and look to see if the rear axle is loose where it bolts onto the swing arm.