Hey Guys,

Out here at the dunes at coos bay OR and need some help. The Trail Boss is giving me nothing but problems this trip. Had to rework the carb this AM and still have to apply choke to get more power out of the quad on hills. But in the meantime it developed a bigger issue this evening.

Relevant info: Bone stock 2007 Trailboss 330. Stock everything except 1 size bigger on the main jet.

Issue: When you first start(especially under load like on a hill) you get a popping noise can can feel it in your right foot. Have checked the chain and it is not lose or slapping that I can see. With the rig in the air I cannot reproduce the noise/feeling. Spun the axle slowly and cant hear any issues.

Also, I bury in sand intentionally on hill, then it make a really bad popping sound, like a chain skipping a tooth. Does not feel good.


Help! Any suggestions?

 

Welcome to the forums.

You checked the chain, but did you check the sprockets as well?

 

If the external sprockets and chain are ok,especially the front sprocket that can strip splines,then the problem could be the old dreaded silent chain in the gear case jumping teeth because of wear and stretching over the years. Happens a lot especially in machines that don't have a low range.Check the sprockets and chain out closely,if ok, pull up to a tree or post and give it throttle. If it grinds,then probably the internal chain.It's more trouble getting the gear case out of the frame than it is to separate the gear case for a 40 buck chain.

 

Ok, update. Rebuilt transmission today, after a 100 mile round trip drive to buy the chain. End result: Same problem.(Note, chain was very loose so not a wasted day).

Looking at the bike when the issue is occurring shows that the chain is slapping the frame, can see this in paint marks. And when the noise is very bad it looks like chain is going to de-rail. Feels like we are missing an idler sprocket or similar device.... All we have right now is the small drive sprocket, chain, and big rear end sprocket. no plastic, no anything else.

Help!!

 

We reduced the sprocket size last year and bought a new chain(o-ring style of course). After it was installed the plastic parts would not fit, so they are sitting in a box with the factory chain and sprocket 6hrs away from here.

Is this possibly contributing??

 

Most internal chains are loose after a few years.One potential problem at least out of the way. Make sure the swing arm bushings are good,no side to side play that could be causing problems. If that's ok I'd install the chain guard even if it means having to go back to the stock sprocket. The guard protects the chain along with keep it from jumping sprocket teeth. Even though all models after 97 or so have concentric drive(drive sprocket is parallel with the swing arm) and suspension compression has less effect on the chain tension as in previous years, lack of the guard/guide sounds like that's what you're up against.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse