I had the twin of that machine which was my 2005 Prairie 700, actually Suzuki borrowed the design when they were working together there for awhile. The belts last for a very long time, and the clutching is perfect from the factory. You will need a clutch puller to change a belt if you ever need to as it is on there very tight. The belt light comes on every 100 miles telling you to check your belt, and to also reset the belt light. I sold that quad, and if you need help resetting the light just check on the Kawieforums for the procedure if you decide to buy it. It involves switching two connectors in that area and cycling the key to reset it.
The best mod for that engine is to install a DG5 module from Diamond G.
This will not only make the atv accelerate much quicker and faster from a dead stop, but also make it run cooler also, and the fan will run much less because of it. Don't waste your money on a Dynatek aftermarket CDI unless you planned on doing extensive engine mods as by itself it does little to nothing as I tried that route myself before the module.
The rear suspension and rear brakes on these are very good, the rear shock is a reservoir piggyback shock, and the brake is a wet sealed brake. The front struts are ok, but it really needed dual a-arms to make it steer and handle better in the front, but like I said they still work okay, and still put my 420's front end to shame. Remember this is the machine all the utility racers used for years in GNCC racing.
The two biggest downfalls to this machine are the Kawasaki electronic braking system,,KEBS,,and you can not switch to 4wd after getting stuck in 2wd as the machine has to be rolling the front wheels to switch into 4wd. The electronic braking system was why I finally ended up selling my quad as I had to replace the solenoid not once, but twice. The first one was covered under warranty as I bought it new, and the second one I had to buy and it was close to 300.00, and my machine only had 700 miles on it. Even that one started to act up, and I took that one apart and cleaned and adjusted it myself with a thread I found on Kawie forums and took parts from my other two to make it work again. When they act up the 2wd/4wd lights start flashing giving you a code and at that time you cannot use 4wd or have engine braking until it is fixed. They do offer a module from Diamond G to bypass that if you wanted to and then put a KFX700 side cover on the machine to look right to do away with the electronic braking. With the belt being as tight as it is, and the brakes as good as they are you could get away with it in tight woods by just running in Low range to keep the clutch engaged. It still goes plenty fast just in low range so its no big deal if your in tight trails anyhow.
The choke cables are known to give issues also, and the thumb throttle is stiff having two carbs but you get used to that. All in all, if it is in good shape and the price is right I wouldn't hesitate to get it, or another one for myself. I still kick myself for selling that quad and getting my 420,,,yes it's that much more of a machine,,sorry i just say it like it is.
I just got ticked off at the electrical issues finally and stuck it in the front lawn for sale, and sold it in a day. I miss that big v-twin torque and acceleration as it was untouchable by anything else out there back in it's time. It still will pull with a new Canam in a drag race despite the big hp numbers Canam claims. The engine has allot of torque, and never runs out of steam,,you will be smiling from ear to ear if you decide to get it,,,,if you do,,get that Dg5 module, and some stock size 25" radial tires(the stock rubber will kill you on wet grass as this quad breaks the tires loose at over 30mph) and you will have allot of fun eating up most sport quads in drag races, and still having a 4wd for the tough stuff.