I just purchased a Polaris Sportsman 700 07 modle unit.  When I got it home and cranked it up, took it out and drove along it was fine, but the moment I let off the throttle there came a knocking noise from the engine or transmission. I think this strange and wonder if anyone else has encountered this..

I took it back to the dealer where I bought it and had the lead service rep take it for a spin.  he agreed that it has a noise but says that his does as well, just not as much.  Another shop tec took it for a spin and said it was the gears all catching up with the deceleration, and since the drive belt, engine, gears, and shaft area all interconnected that it was normal.  

This maching has .5 hours on it and I am wondering if anyone else has encountered this problem.....  

actually it isd normal for a polaris to have this noise.

it's caused by excessive slack between the gears.
it is a design flaw but you'll never get a polaris dealer to admit it.
i have some pvt gears here at the house that have a tighter tolerance.  they would probably fix your problem.
you are welcome to them if you'll pay shipping.  

Is this dangerous? will the thing blow up if running at a high rate of speed, or is this just something that cause the machine to get worse and worse and eventually break down and require an overhaul?

I've had the dealer note in  their computer that I was there concerning this problem and will everytime I go out and ride it. I will probly even call the Polaris service dept and do the same thing.....It doesn't seem right that one throws down 9000 on a new machine and this is what he has to put up with......I thought Polaris was a good name with a good quality product...thats why I purchased from them in the first place...  

Is this dangerous? will the thing blow up if running at a high rate of speed, or is this just something that cause the machine to get worse and worse and eventually break down and require an overhaul?

I've had the dealer note in  their computer that I was there concerning this problem and will everytime I go out and ride it. I will probly even call the Polaris service dept and do the same thing.....It doesn't seem right that one throws down 9000 on a new machine and this is what he has to put up with......I thought Polaris was a good name with a good quality product...thats why I purchased from them in the first place...  

no it shouldn't blow up, the concern is that overtime it will start jumping out of gear or will break the teeth off a gear. (and most likely just after the warranty has run out or polaris has found a reason to void the warranty)
polaris has so many recalls, and has had them for years.
and most of them are re-ocurring recalls, meaning the same recalls on more than one year model.
in some states some of the defects with polaris machines were so bad that they fell easily into the status of "lemon atv's"

polaris is co-owned by Fuji Heavy Industries, which only means you have to wonder what part of your atv is american and what part is chinese.

and i understand your frustration. i see it on a regular basis at my shop. customers bring in polaris atv's with very few hours on them with major repairs needed.
and Polaris is aware of their defects but only admit to what they have to.
and i believe this is because if they admitted to all of their defects they would go out of business.

there are recalls on some of their atv models for the transmission bolts backing out and locking up the transmission while riding, some for the brake calipers falling off while riding, some for the steering shaft breaking while riding, some for fire hazards that in some cases caught the house on fire if the atv was parked in the garage.  the list goes on and for polaris, and these are only some of the defects they are willing to admit to.

here's a link to a site with the defects for polaris and other machines listed.
http://www.atvsafety.gov/atvrecalls.html  

thank you sir for your help and information....I appreciate it ......  

well I just took my new polaris out for the weekend....runs great except for the knocking comming from the clutch houseing/ engine.  when coasting downhill in gear at a low speed, after the transmission has disengauged, it knocks and thumps in a steady beat untill I either stop or throttle up.  

I took it to the shop...they took it apart and said that "everything was fine"..that it was the belt driven powertrain doing what it was designed to do....I said " you mean it's designed to make this knocking noise? " and they said yes.....

anyone else out there have a 07 750 polaris belt driven quad that makes the same noises...if so, had it always done so?.....is it normal?  

no it's not designed to knock like this, alot of the covers do this either because the cover has slipped so that it comes into contact with the pvt clutch. or because a motor mount has broken allowing the engine to move slightly causing the clutch to come in contact with the cover.
eventually it will wear a hole in the cover and your belt will either dry rot from dirt or get wet and wear irregularly. (and at $45.00 each, replacing belts can get expensive)

but the dealers don't like to honor the warranty so they'll tell you anything at polaris.

there are so many defects with polaris machines that if polaris was responsible and admitted them all they would go out of business because they couldn't afford to fix them all.
polaris is completely aware of the lack of quality, but still they do nothing to raise the level of quality.

i have personally tried to get them to honor their warranty for my customers who own polaris machines, even got them to admit there was a defect on several, but they refused to do anything for the polaris owner.

they basically told me as long people are buying polaris atv's they don't care.  

I have an 08 sportsman 500ho and it doesnt knock at all... On down hills even steep all it makes is the slight whine from the ADC unit. Dont let them BS ya

Ken