i would NOT suggest an older lower powered model (such as the timberwolf or the old explorers) in a year he will be saying I WANT A NEW ONE! they are seriously under powered to be a 4x4 model.

i would suggest a bruin or a rancher. I dont care for polaris myself, as every single one of my buddies who has owned a polaris has had a lot of trouble with them (ranging from a lot of small things, to HUGE internal problems) the sportsman series seems to be more reliable than in the past, but check out the weight on them, first, and the extra power of 50-150 cc's is quckly eaten up by the weight.

Model Dry Weight MSRP

2005 sportsman 500 HO ; ; ; ; ; ; ; 715 msrp 6699
2005 sportsman 400 - - - - - - - - - 715!! msrp 5999***
2005 magnum 330 ; ; ; ; ; ; ; ; ; ; 637 - msrp 5249 ***
2005 kodiak 450 - - - - - - - - - - 591 - msrp 6,199
2005 Big Bear 400 ; ; ; ; ; ; ; ; ; ; 556 - msrp 5199
2005 kodiak 400 - - - - - - - - - - 578 -msrp 5799
2005 bruin 350 -; ; ; ; ; ; ; ; ; ; ;538 - msrp 4999
2005 rancher 350 - - - - - - - - - - 524- msrp 4999***

and yes im THAT bored to gather that much info...lol (i dont like putting down false info)

now that its all laid out, in my opinion it should be pretty obvious that being his age and size a rancher/bruin kodiak is best suited for him. (im not taking anything away from your sons ability, but 715 lbs is a LOT of weight to throw around for a 12 year old.)
the magnum wouldnt be a bad, but for the size of the engine compared to the weight it too seems a bad choice.
the bruin and rancher both being under 550, and costing under 5k seem like good choices.

 

Thanks for the info. I will look into the Rancher more. I went to the honda shop yesterday and really liked the foreman rubicon also. Looked like the same size bike.

 

Roost is right about the 715 pounds. I just recently took a ATV safety class and there was a older man that weighed around 175lbs on a new 660 Grizzly. When we were doing sharp turns that quad was on 3 wheels on every corner and he was trying everything to conterbalance it. If you want to buy a quad like that for your son you may as well wait until he is 16 and buy him a toyota 4x4 truck and tear through the woods. I cant say much about having a big quad, I do have one of the largest sport quads, but its balanced correct and slides around sharp turns with me on it. Some of the big quads need a big rider or else you may as well plan on it ending up on top of you or your son. I ended up with mine on top of me and 500 lbs was plenty to break a couple of ribs and Im 190 and 21 yrs old. Hate to see what 400 lbs or more would do to a 12 year old.

 

I own an 05 rancher and love it, for the money a great choice. I am 270# and I too have been riding all my life and I am 29 now. I started with a 185 Kaw 4 wheeler and I still have it but I wanted a 4X4 for Moose and caribou hunting and I keep up with all the big boys in the mud. A samller width and light weight make it an excellent choice. For serious mudding you must get bigger tires like in a 26inch. The realibility is superb. No problems. I trust my life with this machine. 0 degree nights and I don't want to get caught out there.

For the money you can't lose.

 

I have a friend that rides with us that has an older 300 praire and he can go anywhere the rest of us 500 & 700cc machines go. It has even pulled a few of us home when we had mishaps.

The Magnum 330 is a very capable machine too. One of my friend's son has one and he goes everywhere we do too.

If you are looking at 400cc machines why not have a look at an Eiger?

 

I would not get the Polaris 90 if you plan on your kid riding in mud or water. There has been stator problems from riding in water and the cvt will allow water and grime in through a vent hole on the side. This can crud things up and cause belt slippage when wet (among other problems). I'd look at a semi-auto for your application.

 

Well guys and gals if any answered. This weekend I purchased two four wheelers for my sons. Here is how the story goes. I took the wife on Thursday to look at the mini's. She fell in love with the camo sportsman 90 and liked the Magnum 330 dimply again for the camo look. I wanted the Sportsman 400 but it isn't offered in camo. The salesman did tell me that last years Sportsman was offered in a Hunting edition that included camo, winch, racks, camo wheels, and heated hand grips. This peaked my interest but he said they were long gone and pricey to boot. Well on Thursday I went about bargain shopping for the little one and called a few dealers. After the third dealer said we are out of the camo 90s and if you know where one is at get it. I called back to the local shop. You guessedit gone in the last hour. I finally located one 3 hrs away and said put my name on it I'll be there in the morning. I asked if he had another one and he said yes but I was meaning about a larger model for my son. I then asked if he just happened to have an 04 camoed 400 and he did. He said, "If you'll want it I'll make a hell of a deal for ya!" Little did he know I would have given premium for it. Anyway I figured I saved around 2,000 by the time I figured new winch and mud tires on a regular 400. Thanks for all of the advice and keep it sunny side down.

 

ok, ive been riding a 250 since i was about 5, and at the age of 10-11 i rode a 02 sp500 for most of the time, and i only wieghed about 110-130lbs...so yea, it was big on me. i had my fair share of accidents with it, yet i havent had one serious injury yet (knock on wood).

if the rider is responsible and doesnt push their luck, they can handle a larger ATV, as i almost all of my riding experience on a 400+, and im only 16... so i basically had a big ATV at the start, and ive done fine. my cuz is going the same way, riding a sp400...and hes 8 or 9, and it is big for him, but hes VERY careful on it.

as for which to get, for the smaller riders, id say go with a kodiak or a big bear. theyre both light and nimble. they both have more than enough power, yet are tame enough for a smaller rider. my mom wanted to get one, and she fell in love with my kodiak because it just feels good for a smaller rider, and even bigger riders can fit comftorably as i am 6'1 and i still play around with it.

do not get a sportsman, as it really is heavy, i dealt with it, but wish i got a kodiak earlier....