Take your exhaust cover off above the CVT there are four springs that when cold or heated under the right vibration causes a rattling sound. It happened to me so I zipped tied them together and the sound went away. Try that and let me know if it helped

 

Does it mostly do it when under very little load, say when going down hill and just using enough throttle to maintain speed? Or when going from on throttle to off? If so, try jacking up the rear of the quad, pulling the wheels off and running it in gear. I did so with mine, with the wheels off and not damping the noise it was pretty apparent it was coming from the rear driveshaft. Spline engagement is very short, any wear lets it flop around and make a rattle. Hard to isolate, it transmits through the whole driveline. If you suspect this is your problem pull the driveshaft and see if it goes away. IMO bad design, too little spine engagement and excessive driveshaft angle.

I got away with pulling the boot, greasing the spline with a really sticky marine grease and putting it back together. While bolting the final drive in place I pushed it forward as much as possible to get more spline engagement. Cut the noise 90%

 

@ BestJr the four springs are tight.
@ brianidaho it happens when under very little load, say when going down hill and just using enough throttle to maintain speed. I greased the spline two days ago with no success. Also now the red engine light is flashing, over the display runs, "CHECK ENGINE". The footboards ar under strong vibrations at 50km\h and above.

 

my buddies 650 started that this weekend in the mountains! His had a growling sound coming from the gearbox area at about 20ish miles an hour and then this weekend when in the mountains it changed over to this rattle at cruising speed with just enough gas to coast along.
He said if you nail the gas it seemed to go away and that it only did it when coasting down hill and was light on the gas!
sounds similar but I wonder why his was growling first and then changed over to the rattle. he said he was able to feel the vibration coming from the gear box when he reached down and grabbed it.

so you think this could be the rear drive shaft? it does seem like it isn't perfectly round!

 

One of my Renegades has been doing the exact same thing and I haven't found it yet. It only makes a noise when you are not on the gas very much, almost coasting. If you gas it, it quits making the noise. I jacked it up and it seems to be coming from somewhere around the tranny. I felt of the driveshaft but it doesn't have any more play than my other Renegade which makes no noise at all???????????????????

 

:th_smilieofftopic: Badride, when are you going to give us some updates on your SxS?

 

Could it be because the gears in the tranny are cut sraight instead of an angle that is causing this noise when light on the throttle?

 

sorry to bring this old thread back to life... but i have run into this problem now too. had anyone figured out what it was?

 

I can tell you that we are still working on my buddies 650 trying to isolate his rattle. so far we put it on the lift and tach'd it up to about 4k rpm's in low and it started rattling like crazy! I got under it and grabbed the shaft and shook it loosely and it gave a little bit of chatter (at the splines with the play in it). We put a mechanics stethoscope on the gear box and it was terrible but I'm still thinking for sure it's just traveling thru from the shaft!
We took the shaft off and of course nothing, the noise went away.. but of course without any load on the gearbox if the problem was in there then it would probably be quiet to!
So we took the boot off and packed more grease in the joint with the splines and tried that. Of course that didn't fix it, AND I could still grab it and shake it enough to get chatter!

Then we put my 800 on there and tach'd it up trying to see if any noise was there and we actually could here it very low at high rpm's in low gear too. I have NEVER heard it while riding but we heard it very slightly then. So in comparison another thing we noticed is that my shaft has a slight wobble to it and is not true.. His has a LOT of wobble and is definitely not true (straight)

So tomorrow we are going to pull my shaft off and put it on his bike and see if it rattles and we will know for sure if it is in the shaft or more in his gear box. I still feel 99% sure that it is the shaft but we will see!

I'll keep you all posted on how it turns out!

:th_smiliethumbsup:

 

check out your rear drive shaft, i figured out what was causing the noise, i took it down the road an my dad followed on his wheeler, the rear drive shaft is bent! i couldnt believe it, goes to show how much power these 800's have! haha :th_smiliewoo: now hopefully warrenty will cover it...

 

Here's the update. We started today by jacking up my buddies 650 on the lift and tach'n it up in low gear. At approx 5500 rpm's it began the horrible rattle. So we took the brake caliper off and got the exact same result (excluding the rotor/brake contact).

So we then took the complete rear shaft assembly off and then dropped the bike and rolled it out of the way. We got the rear shaft out of my 800 and put on there and absolutely no noise at all! Tach'd it up to 7500 rpms without a hint of rattle!!!

So his bike went from a growl or whoom whoom noise (as he called it) to a pure rattle and it was all in the shaft. When he had the noise it came up thru his snorkel (CVT) and from the mechanics stethoscope it was bad in the gear box.. BUT today we proved it ALL came from the rear shaft!

in comparison his rear joint was very loose as compared to mine so it probably is all in that!

Good Luck

 

Here's the update. We started today by jacking up my buddies 650 on the lift and tach'n it up in low gear. At approx 5500 rpm's it began the horrible rattle. So we took the brake caliper off and got the exact same result (excluding the rotor/brake contact).

So we then took the complete rear shaft assembly off and then dropped the bike and rolled it out of the way. We got the rear shaft out of my 800 and put on there and absolutely no noise at all! Tach'd it up to 7500 rpms without a hint of rattle!!!

So his bike went from a growl or whoom whoom noise (as he called it) to a pure rattle and it was all in the shaft. When he had the noise it came up thru his snorkel (CVT) and from the mechanics stethoscope it was bad in the gear box.. BUT today we proved it ALL came from the rear shaft!

in comparison his rear joint was very loose as compared to mine so it probably is all in that!

Good Luck

was it bent??

 

Bending of the driveshaft, as well as wear in the splines seems to be pretty common. It's a poor design, there is excessive offset between where the gearbox output and differential input shafts. This puts a lot of stress on the u-joints and the rest of the drive shaft. Add to that a very limited spline engagement, it's maybe 3/4 of the shaft diameter and it's a problem. Mine doesn't have much play...but enough to cause noise. I saw on some other forums that guys that have heavily modded Gades bend shafts pretty regularly.

I took my driveshaft to a local shop that builds 4x4 driveshafts, figured we might be able to come up with some automotive parts that would beef this up. No go-the only thing that used our u-joints were early Samuris and the replacement parts are junk, he advised not to bother.

We buy splines and spline nuts from a company for our products at work. Some day I'll look at rebuilding a drive shaft with these parts and see what I can come up with.

BTW, I think the drive shaft assy is around $275 on line, over $300 at my dealer. BOHICA