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Discussion Starter #1
I have a 96 sportsman 500 4x4. It starts ok revs up good till thto unt thumb throttle gets about 1/2 way then it seams to break up. At an idle it seams to speed up and slow back down at random, not much but noticeable. I got this as a project as I'm getting to old to hunt without some help if I get something. I had done allot of reading and even had a friend who worked on these things help. From the start after I got it all together the same problem with the breaking up has been happening. Change the cam, valves and rockers. Change the carburetor. Changed the CDI. Cylinder and rings good. new top end gaskets. Checked the timing, good. Compression good. Unhooked the reverse limiter. All new parts still the same. Is there some sort of over rev setup on this motor if the limiter is unhooked???? At a loss, I have a $1000.00 in new parts a little better but still the same. At a loss need help.
 

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Yep, those machines pretty much require the air box/intake be hooked up and sealed tight to run right. Check the intake boot for cracks/leaks with a couple squirts of ether while its running.

The surging at idle sounds like a carb issue.
You said "changed the carb"...to new or used? ...was the diaphragm or pilot screw messed with? (ie. the tiny spring,washer, o ring properly installed?)
diaphram leaking, misalligned, pin hole?
...impulse line checked for leaks/cracks? ...vent lines clear?

Breaking up at higher RPM sounds like a limiter/cdi issue that is common for those late 90's machines.
You said "replaced cdi"...New? ...correct part?
You said "unhooked the reverse limiter" are you talking about disconnected the button or have you removed the black wire from #31 under the hood?

4060135
LIMITER,RPM,LR83,HUB GROUND

 

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Discussion Starter #4
Yes all parts are new including the carb. I noticed an adjustment screw on the bottom of the carb. I left it the way I received it as I couldn't see how to get a screwdriver in to adjust it. With all these new parts I'm at a lost. Been looking at finding some one in my area to talk to by phone so I could explain it better with no results. Like I said the limiter was unhooked. Does that run something else that could be maybe back feeding even with the black wire unhooked?
 

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Discussion Starter #5
The CDI info is here





POLARIS CDI BOX
by Ricks Motorsport Electric
Body & Frame Parts
POLARIS CDI BOX
Rollover to Zoom
Description
CDI box enhancements include one or more of the following - multiple spark, increased rpm redline and altered ignition advance curvesAdvance curve allows ATV to rev at higher rpm and quicker rateAlso may be used to replace defective CDI box on stock machinesThis Item Fits the Following Applications:2002 Polaris Sportsman 4002002 Polaris Ranger 2x4 4252001 Polaris Sportsman 4002000 Polaris Sportsman 500 4x42000 Polaris Sportsman 3352000 Polaris Scrambler 500 4x42000 Polaris Magnum 500 4x41999 Polaris Worker 5001999 Polaris Worker 3351999 Polaris Sportsman 500 4x41999 Polaris Sportsman 3351999 Polaris Scrambler 500 4x41999 Polaris Ranger 6x6 5001999 Polaris Magnum 500 4x41999 Polaris Big Boss 500 6x61998 Polaris Sportsman 500 4x41998 Polaris Scrambler 500 4x41998 Polaris Big Boss 500 6x61997 Polaris Xplorer 500 4x41997 Polaris Sportsman 500 4x41997 Polaris Scrambler 500 4x41996 Polaris Sportsman 500 4x41996 Polaris Magnum 425 4x41996 Polaris Magnum 425 2x4
 
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