okay update, I took the atv apart this morning following the book and yup the camshaft exhaust lob is wore right to nothing and the exhaust rocker arm is all scratched and scored up. I bought a new camshaft and a new exhaust rocker arm and a new gasket kit. I feel good about this and want to thank you for your help!!! thank you!!! but I have a few more question, I feel really nervous about making sure that my timing is right.. I have to replace the recoil cover because I noticed it is cracked with a few holes in it, is it okay to take that off with the top of the motor apart? All the metal that is gone from the exhaust lobe, where is that? anything I should do to try and get that out? also just a general question- Any insight for anything I should check or look at while I have it apart?
Thank you thank you thank you thank you

 

You can take the recoil off as long as you don't turn the crank shaft when you removed the cam shaft,that is if this is the way you're going to replace the cam shaft. "If" you want to do it by the book the flywheel and stator can be removed and the lower crank sprocket lines up with a mark on the case(tdc) and the cam sprocket index pin lines straight up with the center of the head on the cam for the timing. Just look at your manual! As far as the shavings you need to drain the sump plug and also remove the oil tank screen filter to clean the shavings,plus prime the oil pump. Again your manual shows this procedure.

 

Ya I will just wait until I install my new camshaft. I do not want anything to happen... Thank you. I found in the book where is talks about priming the pump and all that good stuff. Thank you it is unreal how that lobe was worn.

 

Common problem on these year models. Here's one that probably looks like yours and what most of the ones I found looked like.http://forums.atvconnection.com/pola...ml#post3165857

 

Yes that is exactly what mine looks like, I have a friend that has an 03 Polaris sportsman 500 and he saidiI should run 0w40 full synthetic but the clymer book I just got days to run 10w40 full synthetic. Do you know what I should run? My Polaris dealer sold me PS-4 5w50

 

0w40,5w40,5w50,etc as long as it's good oil and full synthetic.

 

I understand okay probably better to run 5w-40 or 10w-40 in the summer and in the winter 0w-40?

 

I have been looking the last year for a metal front rack extension for the front rack on that 98 Polaris sportsman 500 but all I found was the back rack extension... I just thought that maybe you might know where I can find one? thanks

 

Don't know if this will work..http://www.ebay.com/itm/97-07-Polaris-ATV-Front-Rack-Extension-/271125773241?pt=Motors_ATV_Parts_Accessories&hash=item3f205afbb9&vxp=mtr

 

on the Polaris website under the parts catalog it does not list a rack extension for a 1998 but the plastic rack that is on the 1998 is the same part number for 2000 but that part number for the rack extension is not the same as the one that you listed. So hopefully someone down the road will start making them again, thank you for looking though... I have another question though, you have been doing this your whole life and worked on a lot of these wheelers... I have had to replaced the rear two u-joints and the rear spindles because the u-joints let loose... It makes me nervous that the other u-joints are close to their way out... would you recommend changing them even knowing that they are not loose? and is there any maintenance items I should consider replacing or keep my eye on? friends are also telling me to "upgrade" the machine like rejet the carb is it worth it?? hope I am not asking to many questions just trying to pick your brain... thank you