Hello, I just got a 2005 Trailblazer 250 for my kids to ride out on our place. Looks really clean, really good shape except for this rattle/dragging noise.

No noise when in nuetral revving or anything
Doesn't make much noise when going slow, none I can tell in reverse
Chain was loose, but I tightened it up, could probably go more, it still seems like it's rubbing on the metal swingarm...
Nothing feels like it's slipping


Here is a video clip of the sound it's making with my son driving
https://www.dropbox.com/s/50f16evltf..._0355.mov?dl=0

If the video doesn't work, here is a sound clip of my son driving by


Thanks for your help!

 

Hard to tell with my ears not being as good as they once were,but jack up the rear end and roll the tire forward slowly. Check for any bearing crunch from the rear carrier housing,plus check for any stiff links on the chain or any tightening or loosening on the chain as it turns. If so,I'd replace the chain.If it's not a chain,sprocket or bearing problem,possible you have a worn silent chain jumping teeth in the gear case or slapping around. Another common problem on these atvs after they had a few years on them.

 

Thanks!
The chain seems pretty dry and was loose. I tightened a little, but it might need more.
I will do some more checking on the chain today and sprockets

Any tests to see if it's the silent chain?

 

If a silent chain is really worn you'd hear a lot of grinding to the point some wouldn't even move,they'd just sit there and grind. One test you can try is to pull up to a post or tree and give it throttle. You should be able to tell if it's a front sprocket or external chain problem.Plus at times you can hear a worn silent chain jump in the gear case before the external sprocket and chain move. I'd still check the drive chain out with it jacked up off the ground along with checking for up and down play on the drive shaft or noisy,crunching rear carrier housing bearings. If the chain has tight spots and loose spots as the tire is turning,then usually time to replace the chain. Don't over look the front sprocket for worn/rounded teeth also.

 

Here is a picture and another video of the sound. To me I think it's the chain rubbing on the "pad" thats on top of the swingarm. Is it supposed to do that?



I put it up on stands and rolled the tires, here is the video of that
https://www.dropbox.com/s/bpxor0jhon..._0359.mov?dl=0


thanks for the help!

 

For some reason it didn't post my reply.

It appears the chain is hitting on some pad on the rear swingarm. Thats where the noise is coming from. Looks like its supposed to rid on that, maybe that HD plastic. The chain was dry so it's possible that chain is just junk making the noise worse.

 

Sounds like the chain and front sprocket. Chain looks old,dry and worn plus I'd change out that sprocket also.Rear sprocket is usually stronger and can be reused in most cases. Complete sprocket and chain kits are on ebay for these,but make sure you get one with the oem style o-ring chain. Or you can get the sprocket separate,have a cycle shop cut a good DID,Regina,etc o-ring chain to the length you need. 76 link chain needed. 11 tooth sprocket. #3221043

 

Front sprockets wear out faster than the rear because they spin a lot faster.

 

thanks for that! Will get a new chain and sprocket.

 

I replaced the Chain and both sprockets and still no difference.... I think the issue is friends is that the rear axle and where the rear swing arm are clamped together to hold it once you tighten the chain are wore out and it is letting the axle spin back forwards therefore the chain will not stay tight enough. That that is my diagnosis anyways. Simple solution just get another rubber pad and double it up on top of the other one and it will raise your chain up away from everything and also keep it a little tighter at the same time, problems solved.... 😉