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2002 500 Sportsman won't rev

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  #11  
Old 08-18-2013, 11:44 AM
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Good enough as long as the index pin is dead center of the head and is on TDC on the recoil case pointer..Cam chains were pretty long lasting and tough. The only major problem(didn't happen often) was for the lower cam sprocket slotted nut to back off,causing timing to jump.You'd really know if it did.
 
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Old 08-18-2013, 07:50 PM
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I think I found the problem. I pulled the flywheel off and the key was sheared. It looks like it has also damaged the flywheel. It's got a nice little gouge in the key way. Of course I have looked all over town and can't find a key that size, I guess it is metric? It's somewhere between an 1/8th & 3/16th. After not being able to find one, I rotated the key 90 degrees, and put it back together so the keyway was lined up on the crank and the flywheel, and cranked it a few times and it still doesn't sound right. sounds like the timing is off when it's cranking. Do you know what size the key is? Looks like a may have to replace the flywheel as well.

Before I found the flywheel problem it would start if you held the throttle wide open but didn't run very good as I let off of the throttle it backfired and died. It also seemed to get pretty hot in the short time it was running.
 
  #13  
Old 08-18-2013, 07:56 PM
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5mm flywheel key. A good hardware store like Ace should have it. If you're this far I'd pull the stator plate also and make sure the slotted nut holding the lower cam sprocket is tight.Lower sprocket is keyed also and the nut is reverse threads but can back off..
 
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Old 08-19-2013, 08:32 PM
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Hey, Thanks for all the info. I will get back to it as soon as I get a chance. I have a full time job, so I work on this thing as time permits. I'll let you know how it comes out. Once again thanks for all your help
 
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Old 08-21-2013, 08:16 PM
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Well i finally got a chance to look behind the stator plate. Not sure how to get the slotted nut loos on the lower cam chain sprocket. I hate to mess the nut up trying to get it off but of course i dont have the tool that i need. There is a little slack in the chain. I think it might have jumped time. I have a picture of the upper sprocket when the flywheel mark is centered on the center line, but don't know how to add it to the post.
 
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Old 08-21-2013, 08:29 PM
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Old 08-22-2013, 08:11 AM
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Easy to loosen the slotted nut on the lower sprocket. Just use a flat punch. It's reverse threads,just tap it to the right to loosen,then you can screw it back to inspect the sprocket and woodruff key.Use lock tite on the threads,screw the nut back on and stake it with a sharp blow with the punch. If the chain is sloppy then might be time to replace it.
 
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Old 08-22-2013, 08:17 PM
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I got the slotted nut removed. aligned the cam sprocket at 12 oclock, and the crank sprocket lined up with the mark on the housing. Looks like everything is lined up as it should be. Yet it still seems to me like it is out of time. Could the play in the timing chain be causing that? Or would you think it would be more like the cdi? Man, I'm in over my head on this thing.
 
  #19  
Old 08-23-2013, 03:19 AM
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As long as the bottom crank sprocket mark aligns with the mark on the case and the cam sprocket index pin is dead center of the head,the cam timing should be good. As far as it running right,if the spring from the cam detent lever has slipped it can cause it not to run right. If you think it might be an electrical problem,use this pdf link to a good service manual that can help you on electrical checks.Index of /ORV Manuals/Polaris/Sportsman/2002
 
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Old 08-25-2013, 07:35 AM
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I have been through all of the electrical testing listed in the manual, thats how i found the pulsar coil bad. But as far as the cdi unit, the manual says there is no test for it. I have suspected the cdi from the beginning. If i knew it was bad i could get him to buy one, but he just won't take a chance on buying one without knowing for sure. At this point i have put it all back together and i'm done with it. I guess he'll just have to take it to a dealer. I thank you again for all of your help.
 


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