Looking at buying a used ATV before an elk hunt this fall. Are there any reputable sites for helping determine the value of specific brands or models? something similar to a KBB but for ATV's? Frankly, I have no clue what Im looking at, so some reference material on values would be good.

In addition, what the minimum size I should be looking for in terms of CC's?

where will you be hunting? in NF or private land? are you looking for a 4 wheeler or a side by side type vehicle?

The values can vary quite wide depending on year, make/model/, condition, hours/miles, upkeep/maintenance, etc. I don't have any idea on a online or printed guide for these, more so just experience with various make/models.

there are several online services like KBB, NADA and ATV Trader but I have no idea how accurate those are.

Short answer is they are not accurate whatsoever for machines over 5 years old generally.

I have bought, fixed up and sold countless four wheelers at this point and have found in nearly every instance these guides show values significantly lower than what the machines are worth.

You can get away with anything 400cc or larger, larger is better in your case for elk but you don't want too big at the same time. IRS (independent rear suspension) is a must on a hunting machine, in my opinion.

What is your budget? I can try to help steer you in the right direction as far as makes and models based on budget.

https://www.nadaguides.com/Motorcycles/2009/Kawasaki/KAF620R9F-MULE-4010-TRANS-617cc/Specs

Just use this link and then go to the home page. If you know the vin # it will help

If you are going high and using not well defined trails stay away from chain-drives, previously stated at least 400 CC, side by side great on defined trails otherwise not, have got a Kawasaki Bayou 500, they are not made anymore but it was great in the Umcompadre National National Forest near Ridgeway Colorado. Don't elk hunt anymore but got two nice bulls when I did. Put a boat winch on the front of mine which came in handy on every trip. When is your hunt? If you buy a used one be sure and have it checked out by an ATV mechanic not auto mechanic.

Nothing has been mentioned about carburetor versus ERI type models on higher altitudes.

We have an older Sportsman 500 with the backup pull start,that option
is great if you can find if.
500 cc would also be my recc.
The independent suspension is also great but since you'll be on a marked trail or road not a deal breaker. A winch can come in real handy for moving trees and hoisting quarters.

Keep it 50 inches or under on width.

I wasn't sure if you can take any ATV on NF trails without a sticker, and even then a lot of trails that I have seen are marked no motorized vehicles past a certain point. Check where you are going first to see if these are even allowed.

Buy the largest CC you can afford. My old carburated grizzly 660 felt like a 400cc at elevation. The Polaris general will run 70sih here in texas, tops out around 60 at elevation. Not 100 necessary but its food for thought. I would 100% lean towards efi, if not you need to retune the carb when you get there so it doesnt run too rich and you melt a pistol when its struggling.

ATV will get into places a UTV can only watch as you drive thru.
4x4 will get you twice as far from civilization as a 2x4 before you get stuck.
A big 4 Japanese (Honda, Kawasaki, Yahaha & Suzuki) ATV/UTV have quite a leg up on everybody else design and engineering wise from so many directions it's not fair - if you need evidence, just look at everything motorized that Honda excels at.
Quite a few older utility ATV machines have a pull starter just in case - only needed it once but it was nice that time.

I tend to use my vehicles on my small ranch so reliability is nice since they do get worked and my choices are:
2002 Honda Rancher 4x4 with rear basket goes everywhere and will haul a decent amount with good floorboards that keep mud off your feet.
As I get older, an old 2005 3010 4x4 Mule goes almost as many places since I have cleared roads and hauls a LOT more and I can keep often used tools in it all the time.
The Honda Rancher sits more and more while the Mule starts the morning feeding the cows and goes and goes all day.....comfortably.

have to believe there will be many for sale over the next 60 days.

The smallest mandated MV(excluding Idaho motorcycle dirt bike) trails are 50” and then go up from there.


Go with EFI but get a NF map before you buy one so you know if you can even drive one, beyond normal road

State stickers are easy. Most you can buy online

Colorado/National Forest land. Looking at a single person 4-wheeler, mostly decided that because there is a 50" width maximum, and under 50 SxSs just don't seem super practical to me. We will have to get a sticker for the park. As I understood it, EFI was the way to go since a carburetor is likely to need to be changed/tweaked since we'll be going up 8-10,000 ft. Its worth mentioning that speed isn't a super big concern. with conditions as they are likely to be, running over about 35 MPH gets to be pretty damned sketchy. After doing some more reading, it looks like the 600cc will probably be my minimum power requirement

I'll take a look at the "big 4" as mentioned, as well as that NADA book.

OnX Maps is my best friend when it comes to this. there are a TON of <50inch vehicle trails in the area we have been going

Get the Motor Vehicle Use Map, MVUM, and look over the roads and trails open to atvs in the Ranger district you're going to.
You will need to buy a sticker for use on any FS road or trail, sold online at Colorado parks.
Not sure about Colorado but Wyoming definitely has some good trails only open to atvs 50" and under.