Based upon the number of posts which I have read recently about slower midrange and top end performance, on the Sportsman 500, I wonder if Polaris Industries is deliberately de-tuning the 500 series engine. A couple of months ago I had the opportunity to drive a 500 Magnum and a 500 Sportsman and experienced a "flattening" of power at about 30 MPH myself.

In 1996 I drag raced a new Sportsman 500 and got waxed on my '95 Sportsman 400 2 stroke.
Now the tables have been turned and I routinely show my tailight to the drivers of Sportsman 500's. I haven't made any modifications to my engine, gearing, tires, pipe etc. Is Polaris slowing the machines down in an effort to promote safety?

Has anybody else experienced this phenomenon?

 

Thor, I to am asking the same question in search of some help on improving the zip on my Sportsman. Hopefully, some one will reply on this forum with some support on improving the Sportsman's performance.

 

The newer models have EBS, which slows them down. Not sure exactly how much though.

 

Thor,
Did that 96 Sportsman have IRS? or Chain drive?
I have a friend that has a 96 Sportsman 400, it has a conventional rear axle and chain drive front and rear.
The chain drive and "straight axle" setup allows more engine power to actually reach the rear wheels. The new IRS and shaft drive EAT horsepower.. I still wouldnt trade it for a truckload of chains, but the shaft drive takes a lot of h.p. to turn.
And, as Adam said, the EBS system really does rob mid-range and top end...

 

I was told that shaft drive robs 30% of the power verses a chain drive. I don't know this to be fact, just something I heard.

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Four_Play aka davidg

 

It's interesting that this is just showing up. When they first came out with the 500 engine, the 400 explorers could run circles around the 500's and still easily can. About the only thing changed is the EBS, which makes performance suffer slightly, but I seriously doubt that the shaft drive vs. chains rob much hp. I recently noticed that DynoJet at one time had the SP500 listed as developing 18-19 rear wheel hp. Now is states that they are geting above 20 hp stock. Don't know what's up with that. If you look at the power curve, it really tells the story. Just compare the power curve on a SP500 to a Grizz and you can see that when comparing "stock" machines the SP500 gets the low end jump and the Grizz takes over in mid range and top end. The power curve actually shows the exact way both machines perform in real life.

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

 

Another question. When Polaris redesigned the cylinders on the 96 400 two strokes, did it degrade top end performance?

I know it increased fuel economy.

 

Mudmachine.

The Sportsman which I was beaten in a drag race by was the Sportsman 500 IRS not a 96 Sportsman 400. It just seems that the new Sportsman 500s are not as fast as the older ones. But then again I certainly wouldn't trade the new reliability for one of the older ones.

 

I have no buisness in this post but i think Polaris should put a 600cc or higher in the Sportsman to offset the tremendous weight of the machine. This would allow the engine to remain quiet and reliable like the current 500 but have some real *****.

The scrambler motor is of a good size and power for a bike that weighs five and change but the sportsman is like 200 or 300 pounds heavier. That's not fair. Plus it has those big tires to turn and if you get one of those bad to the bone kits you'll need some torque.

Chris Picciotto
99 Scrambler 500

 

I must have the only Sportman that I feel really performs well,even my top end says 57mph.I also like the powerband.I have a HP clutch kit and 26 inch Mudrunners to.Instead of seeing a 600cc engine,I'd like for the Sportsman to loose about 100lbs.Although,I must say that it is very rare for me to be needing to go 57mph on my tank.I ride with owners of Sportsmans to,nobody really complaining of performance problems.I do know a guy who has a pipe on his,he said he really did'nt see alot of extra pick-up with the pipe.How about the 40mm carb fellows?Anyone tried that yet?====GOOD DAY======BILL

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