Sorry if I dissapoint anyone but I purchased my Sportsman last year in June. Today it is still stock, and it hits 50mph easily. Top speed is 54, on flat terrain. Hook up a Sea-Doo GTX-Limited, and you could fly at 45mph down the highway. (I don't recommend this unless you're helping the cops) A little more top end would help though.

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99' SP500

 

I have a Y2K SP500 that hits 50 with no problem on flat terrain. It will do more but doesn't seem particularly stable at higher mph so I usually back off about then. I did crank up the rear shocks to the stiffest setting and will see if that helps once the weather warms up. Mid range could use a little help but I am very happy with the automatic and EBS. I can't imagine that I would need that kind of speed very often, especially where I ride...mostly heavily wooded trails and very rough terrain.
Sneeky

 

Hi Bill you read it right 50 mph with a tailwind if Im lucky. This was the most dissapointing thing about my sportsman.Falls on its face at about 40mph and son passes me by an his yamaha 80cc. Cant wait to see how bad he leaves me in the dust with his new Trailboss 325. This thing seems to pull twice the revs as the sportsman. Had sthe Sp back to the dealer 3x about top end, even wrote Polaris about it and their reply was that they do not guarentee top end nor do they advertise one.Did a couple of wide open blasts with a new plug and it came out white so looks like carb is too small to me. I even went up a few sizes on the main and its still white.

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99 Sportsman500,2000 trailboss 325

 

I am really not concerned about top speed of my Sportsman, 50 would be plenty. But GETTING THERE is the problem. With the throttle punched and between 25 and 45 mph, I've never heard or felt an rpm increase. Starting to wonder if Polaris put a rev limiter on this quad, but in low gear, I've heard it wind out. Certain a clutch mod would fix this problem, and waiting to hear from others if they have done this. Right now (Sunday) my quad sits idle in the garage, its stuck in reverse and I cannot move the lever. Happened while I was stuck and moving between forward and reverse. I wish they would have placed the lever on the left hand side 'cause your right hand is busy with the throttle...right?

 

Exactly SWAC tone changes but no rpm increase. I had many street bikes and muscle cars never experienced anything like it. Was a huge dissapointment. I have to remind myself though this is a utility atv not a banchee. I thought it would be faster though.I did notice it revs much higher in low range, but wrote it off as not having enough horsepower to rev out in high range.

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99 Sportsman500,2000 Trailboss 325,69 Mustang 428scj

 

I have removed the EBS and have a roller clutch, but it does not eliminate the poor performance curve of the 500 that has been around since it was born. For putzers and cruisers, it's great, but over 40 it takes a while (by my standard) to get to 50 or so. Every one is like that. The motor is a bummer in my opinion. A SP500 with a Grizz motor would really kick ***. The Yama clutch leaves tons to be desired. I think we will find a way eventually, but clutching is absolutely not the answer with a low power unit like the SP500.

<A HREF="http://www.godigital-design.com/96Polaris.html">Schultz Motorsports</A>

 

I agree with jack motor leaves something to be desired. Ive have lots of hypo motors in my life and this is not one of em.

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99 Sportsman500,2000 Trailboss 325,69 Mustang 428scj

 

Hmmmmm, Grizzly motor in the SP500........

Glenn.

 

Mudrunner,

It appears that you have thought about this power situation more than the average bear.

" Somebody was talking about transplanting an H.O. cam into a Sportsman about 3 weeks ago on
here..."

So it appears that there is a different cam available for the 500 Engine.

"... or if the head designs ended up being different. (port design, valve size, piston design)"

We need somebody with access to a parts catalog.

" Oh, If you are going to make this camshaft swap.. Remember that the H.O. Camshaft probably has it's power in a different RPM range than the Sportsman.. So initial clutch engagement RPM will more than likely have to be changed.."

With the right grind on the cam, the power would not drop off once the machine hit 35 or 40. The power curve should be similar to a v-8: Induction, duration, and exhaust.

I also think that SWAC may be on to something with the limiter. I know they put them on the 400 two stroke as I have "bumped up " against the limiter while using low range with a heavy load on the machine.

They could very well have a limiter on there.

But basically we need to hear from the gentleman who ordered the cam and somebody with a parts catalog.

 

I OWN A SP335. IT HAS THE SAME TOP END PROBLEM. GRANTED IT IS ALSO A MUCH SMALLER POWER PLANT. I INCREASED THE TIRE PRESSURE TO 8 PSI EACH. THIS GAINED ABOUT 3-4 MPH. UP TO ABOUT 37MPH. I INSTALED A EPI PERFORMANCE CLUCH KIT ABOUT A MONTH AGO. IT IMPROVED MID-RANGE CONSIDERABLY, AND MADE LOW RANGE MORE RESPONSIVE. NO TOP END IMPROVEMENT THOUGH.

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