I've not operated a RTV900 so its kind of hard for me to compare. Our 6x6 is one axle longer than a atv but we do use it on more narrow of trails. Sorry I can't give more specific of an answer....
Do your units have the locked rear axle? I find that's what causes so many UTVs and ATVs to not have a good turning radius. With the rear tires having to turn at the same speed they tend to plow straight ahead. The rear diff in my Can-am Defender has a switchable locker; I run the diff as an open unit most of the time because that will allow it to turn on a dime. But the only ATV I've seen with a switchable rear diff was one model of Kawasaki. If I want my Yamaha Kodiak to turn sharp I have to lean hard opposite the turn to get the weight off the inside rear wheel so it can spin.
To the best of my knowledge, I've never seen or certainly used, an ATV or UTV with a solid or locked rear axle.
The problem most folks who get into the Japanese minitrucks, is that most of the folks buying them havn’t ever worked on anything. Not even tuned up a lawn mower.
Most without some kind of turf mode are locked.
No rear differentials on Kawasaki ATVs anymore. The old Bayou 2WDs had them, and the Police trike did (for service on pavement).
No Yamaha ATV that I know of has a rear differential that is unlocked. There is a differential, yes, but it is permanently locked so both rear wheels have to turn at the same speed all the time. Same with most UTVs, especially the "sporty" ones. Some of the Utility UTVs have, as stated above, "Turf Mode" to let you unlock the rear diff to enable it to turn sharper and to keep from tearing up turf.
A differential is a gearbox that allows 2 wheels to spin at different speeds. If the the 2 rear wheels spin at the same speed all the time, you have a fixed "final drive", not a differential. It is a fixed final drive gearbox (pumpkin) whether you have independent suspension with 2 half-shafts, or a "solid" rear axle (non-IRS).
OK, fine. Fixed final drive
It is an important difference. 4x4 ATVs have a differential in front (limited-slip), and a simple ring-and-pinion final drive in the back. Finding one with a differential in the back is difficult, as well as buying used final drives on eBay as many folks use the wrong term.
I don’t know for all 4x4 ATVs but am not aware of any with a limited slip front. Am not aware of any limited slip on the front of cars or trucks. The outer tire must turn much more than the inner.
Well, don't take my word for it. Go look at the parts diagrams, which are free on the internet. I doubt that any 4x4 ATV does not have limited-slip diff in the front. They rarely fail, so most folks will never see the actual mechanism.
Yamaha Grizzly 700 doesn't. It's open or locked (Electronically via handlebar switch). I actually think most are this way unless there is no switch to engage the locker.
The Terrapro did have a rear differential that you could unlock for finish mowing yards. Here is a video of a guy working on one and testing the feature.
My mistake. Part # 28 on the parts diagram for "final drive". The Yamaha TerraPro YFP350 was a unique and rare 2WD ATV made in the late 80s. Most unusual was its PTO. (And rear diff.)
