To be honest with you if the Sportsman you have isn't fast enough for you,I would consider one that was. To make any appreciable difference in speed would involve engine and other modifications that could end up voiding your extended warranty.Sometimes hard to have both.

 

 

When you say faster, how much faster are you looking for?

ECU flash did more for my bike than the power commander I had, but it also voids out the warranty on the ECU and they can go as far as saying any device it controls. That's a lot of warranty to be throwing out for a few extra mph's.

 

Which Sportsman do you have? You can put an aftermarket exhaust and maybe a higher flow air filter but that's about all you can do without voiding the warranty. Probably wouldn't gain you much, maybe 2-3 mph on top end. I wasn't even aware that an aftermarket ECU would void the warranty but I guess it makes sense. As OPT said, its easier and maybe even less expensive to just trade up to the next most powerful model. I'm guessing you have a 450 as even the 570 would seem to be fast enough for most anyone or at least it would be plenty fast enough for me, 65 mph is pretty fast for a 4x4 utility atv. The 850 will get you up close to 80 and the 1000 will exceed that. Either of those seem like overkill for most, there's almost no place I could ever go that fast unless I took a trip to someplace with some dunes and really wide open spaces. I'm actually considering getting something with less power for my next machine as it will cost less, use less fuel and be smaller and lighter. I just don't need extreme power and speed for the kind of riding I do. Something that tops out at 50 mph would be fast enough. Even might go with just a smaller 2wd machine as I seldom use 4x4 most of the time. I have a small shed to store both my atv and lawnmower, a smaller atv would give me a little more room.

 

If you have engine problems after switching to a different type of air filter, like a K&N for example, good luck getting warranty coverage. My 500 does about 55 MPH. That's fast enough for me. I can only go 15-20 on most trails anyway. But if I wanted something faster on the roads I would get something bigger like the 1000 my friend has. Actually, I think we're only supposed to go 20 MPH and only on the shoulder of the road. Not flying down the middle of the lane at 80 MPH. But on the trails you can go as fast as you want to.

 

Never been on any trail system that you could run more than about 40mph, I suppose you could out west in the wide open spaces but what a bore just going like hell in a straight line waiting for a tire to blow out so you can fell pain for weeks and weeks.,,80 mph machines just don't make any sense to me....then wait until your insurance company finds out...$$$$$

 

Some ATV trails and routes here have sections that are marked mixed traffic. Basically they're just dirt roads through the woods, ranging anywhere from 2-tracks all the way up to fire roads 3 cars wide. Any vehicle can legally drive down them. I might putt along for several miles on a trail, then instead of the trail going straight across the road, I can fly down the road until I have to turn back on the trail and putt along again. It could be 50 feet on the road or a few miles. If you keep going past the sign telling you where the mixed traffic ends, instead of taking the trail you can get charged a hefty fine.

Even when there are miles of roads I can ride, I don't like going faster than about 45 MPH. If there's any kind of catastrophe, I can probably survive a 45 MPH crash without breaking many bones. Then again, I have osteoporosis and might get mangled. A lot of people don't realize that when you double the speed of an object it doesn't just double the amount of energy it has. It's 4 times as much. If you crash at 80 MPH you'll hit 4 times as hard as you would at 40 MPH. You won't be getting up and walking away from that unless you're unbreakable, or very lucky.

 

Speed isn't everything anyway. Power isn't necessarily always about speed. Many people buy the bigger bore machines to turn bigger tires, overcome high altitude which robs power, and get through stuff like sand, mud, and snow, all of which eat power. I used to occasionally go fast but I realize now that if anything had happened, I might have gotten seriously hurt. My Brute Force when it was running perfect would top 65 mph, hit 67 mph once when i ran it flat out to see how fast it would go. I hate to think if I had crashed at that speed or hit an animal like a deer. Even something pretty small like a raccoon would probably wreck an atv. I almost hit a turkey once, that probably wouldn't have turned out well. A few relative near misses with deer at much slower speeds as well. A lot of critters on our local trails for sure. I hardly ever even ride at night, I hate that you just can't see what's out there nearly as well as daytime. I'm sure I could put on brighter headlights and/or add auxiliary lighting but its still not the same as riding in the daytime.