Beast chain keeps popping off

[jiggypiggy]

The chain on my gio beast keeps coming off. I've heard you are supposed to check the tension. Not sure if there is a tool you have to use for this but if I push on the top of the chain loop, there is only about half inch of play. The bottom of the chain loop has quite a bit of play. Also, close to the rear "sprocket?" thing that the chain goes on, on the rear tire axle, there are 2 large brass rings that screw on close to the sprocket. No clue what they are for but they somehow came loose and right off. I tightened those up but they still come loose. Is that somehow related to the chain issue, or a separate issue?

[bogieboy]

if you can show us pics of the brass rings youre talking about, it might help with the diagnostics.
just shooting from the hip here without the pics but sounds to me like the chain is too loose, and possibly the sprocket is coming loose, which would throw the chain very readily...

[Weldangrind]

X2 on pics. There were two different axle styles on the Beast, and we'd need to be sure of which type you have.

[jiggypiggy]

K, hope these help!

http://imageshack.us/a/img826/9243/erhc.jpg
http://imageshack.us/a/img802/5476/emme.jpg

[FLASHLIGHTBOY]

ok... those brass things.... are you lock nuts for the drive gear ... those have to be tight... use some BLUE LOCKTIGHT on them if you have to...... next ... you have to loosen the top & bottom bolts so you can tighten the chain...... do this in this order...
first... LOOSEN THE 2 BOLTS ON TOP
LOOSEN THE 2 BOLTS ON THE BOTTOM WHERE THE ADJUSTERS ARE( BOLTED TO THE AXLE HOUSING....
LOOSEN THE FIRST LOCK NUT ON THE ADJUSTERS
TIGHTEN THE LEFT NUT TO CAUSE THE AXLE TO BE PULLED BACK THIS WILL TIGHTEN THE CHAIN.......]
ONCE THE CHAIN HAS MOST OF THE SLACK TAKEN OUT... DEFLECTION 1/2 TOTAL.... UP & DOWN ..IN THE CHAIN....
THIS IS THE KEY PART........ MEASURE FROM THE FRONT RIM TO THE REAR RIM..... MARK DOWN DISTANCE...
MEASURE RIGHT SIDE .. RIM TO RIM....AS YOU DID ON THE LEFT... THESE HAVE TO BE THE SAME...
USUALLY THE RIGHT SIDE IS FUTHER BACK THAN THE LEFT SIDE..

USE A 1 INCH RATCHET STRAP ....HOOKED TO THE RIGHT A ARM... BRING THE STRAP OVER THE REAR AXLE... AND BACK TO THE A ARM... RATCHET THE STRAP TIGHT TO CAUSE THE REAR AXLE TO BE BOUGHT FORAWRD UNTIL THE DISTANCE IS THE SAME LEFT SIDE & RIGHT SIDE....

TIGHTEN ALL BOLTS ON THE REAR SUSPENSION.. THE 4 BOLTS....2 ON THE TOP... 2 ON THE ADJUSTERS.... THE CHAIN WILL NOW RUN STRAIGHT & STAY ON...
PLEASE REMEMBER TO BACK OFF THE LOCK NUTS ON THE RIGHT SIDE BEFORE USING THE RATCHET STRAP... AS THE ADJUSTER NEEDS TO MOVE FORWARD...
THE RIGHT SIDE IS ALMOST ALWAYS FURTHER THAN THE LEFT SIDE... CAUSING THE CHAIN TO COME OFF

[Weldangrind]

That sounds a little tight to me. I don't run my chain that tight on my Beast, and it doesn't come off.

If you were to place a jackstand under the quad to get the rear end off of the floor and then remove the rear shock, you could then move the swingarm up and down by hand. If you raise it (perhaps with a scissor jack, if one is handy) until the center of the rear sprocket, the swingarm pivot bolt and the center of the front sprocket are in a straight line, that would be where the chain is tightest.

Once the swingarm droops to ride height, it will be looser. The key is to line up the three points and have a snug chain at that point, but not excessively tight. If it's too tight at ride height and then you hit any bumps, it will wear quickly and probably break the chain.

Beware that the older Beast rear sprockets are not concentric. As you rotate the rear axle, the chain will go from tight to loose. Sucks, I know.

[FLASHLIGHTBOY]

if you look on the GIO SITE.. they will show you the same as I said about how to tighten the chain..

[Weldangrind]

That doesn't make it right. I remember the days when Gio was Giovanni, and John Dem didn't have many parts to sell. Nor did he have a clue how to install them.

We benefit from each other's experience and knowledge.

[TYE]

I'm also having chain issues on the older model 2008. Originally it was tension, which I now adjust to about an inch of play but it is even top and bottom. Check that your swing arm bushings are good. If you can move the ass end side to side you may have worn them out. If you also have the older beast replace them with Yamaha 307-22123-00 these are way better. Also check your alignment, use a flat surface to insure your sprockets line up and that your chain is not being forced off. My problem is the Front sprocket retainer is worn out and keeps falling off. I don't really want to pay $20 shipping for two dollar part so does anyone know a better solution? Japan bikes use clips has anyone upgraded?

[Weldangrind]

TYE, can you please post a pic? I'm not sure what you mean.

[TYE]

I'll try to post a pic soon. The sprocket retainer (which screws onto the sprocket) has grooves that match the countershaft. Well those grooves are worn out making the sprocket slide right off when pulled. My local shops all seem to have The 15t 428 sprocket but not the actual retainer.

[Weldangrind]

I might have one laying around. I'll try to remember to check when I'm next in the shop, but feel free to remind me.