i have a 98 Sport 400 2x4 with a hot seat pipe and clutch kit. i think ive got the jetting down right now cuz it runs nice and strong.

my buddy and i raced today and he beat me about a bikes length each time. hed pull away from the start about 1 bike lenght and then id stay w/ him all the way till we were at full throttle. his is a 86 honda 250R stock with a pipe and thats it. i think its a fat Bros. pipe but am not sure.
Has anyone had better luck or is that good?
thanks for any info.
my tires might need replacement but i dont think that would of contributed much.

 

That's about as much as you can expect. I have a '97 Scrambler with RCR midpipe & cluth kit and v-force reeds. I can take them off the line for a pretty good ways and end up just behind them at the end of about an 1/8 of a mile run. They are so light that once they get into the power band real good in the upper gears they take off like a rocket. The same with the banshees. I can take them off the line but end up fading quick once they hit fourth or so. Weight and gearing is the key here, not power. Until Polaris put's these things on a serious diet, they will never compete with the lighter high performance sport quads. You will have to go a little deeper in the mods (porting & bigger carb) if you ever hope to beat them (banshees and r's)in a straight line. Give it up on the track or tight woods though.

 

peanstein & Sharpe1,

I hate to say this, but what can you expect? The Sport weighs about 150+ lbs more than the 250R. It takes more than a little more horsepower to give you the advantage. It'll take a WHOLE LOT OF HORSEPOWER to beat them.

Now that you have your Sport breathing better through the exhaust you must get it to breath better through the intake side. Get a 39mm Kehin PWK carb, some V-Force reeds, porting and head mods (or cool head), pitch the stock airbox and go with a K&N. You'll be surprised how well these mods will work. You may have to get a longer swingarm because with a motor with that much horsepower, your quad develops some serious handling problems. For one, you can't turn under full throttle because the front wheels are up in the air so much. Check out the link to my web pages below to see what can be done to these older Polaris Sports. My list of modifications is on page three.