I have had my sons 70cc atv for over three years without any major problems.. See my photos for ideas of make/model.. Last year I was changing the oil, and did something really stupid.. I took the bolt out underneath the motor, and a spring flew out... Yes I took the wrong bolt out... I was told that what I removed was for the chain tension???? I did manage to find the spring and put it back together... Located the proper bolt and changed the oil... Even though I changed the oil plenty of time before.. I just wasnt thinking that day.. My mistake...

Now the problem I'm currently having is.. I tightened the chain last year because I noticed when he was riding it looked loose... It seemed to help.. But the last time he went riding the chain came off.. I put it back on, and it was tight while sitting... When he is riding it seems to loosen up.. But when he stops, it feels tight... Is this problem connected to the bolt/spring that came out?? Or is this another problem?? And does somebody have a solution to this??? Thanks!!!

 

Anybody have any ideas??

 

The spring thing that came out is the tensioner for the valve timing chain (inside the engine). This has nothing to do with the drive chain.

I would look for something loose in the back end. Put the rear end frame up on jackstands so the wheels and suspension are hanging free. Check the swing arm bushings for looseness, and all the bolts that hold the rear axle in place. Also look at the alignment between the drive sprocket on the engine and the rear axle sprocket.

Chains should not be tight when sitting. You must allow a little free play (1 inch deflection in the middle of the chain). On most quads the chain path lengthens (chain gets tighter) as the rear swing arm bottoms. If you don't allow that free play in the chain then something will have to give when you hit a bump.

 

When I mean tight.. Its within specs... When he starts moving(fast) the chain flops around.. But when he stops, it feels ok.. I will check everything suggested this weekend... Thanks

 

Is the chain comming off?
A comstant chain tensioner may be the answer if needed.

 

The chain has fell off once.. Where can I find a constant chain tensioner for his atv???

 

TRACTOR SUPPLY IS WHERE I GOT MY TENSIONER.YOU WILL HAVE TO MAKE IT FIT YOUR NEEDS