[img]i/expressions/face-icon-small-confused.gif[/img] My 99 sp500 is sick, almost on it's death bed in my book. It will idle OK but when put under load it starts missing out, getting hot, back fires. below is a list of things I have done to bring this once awesome machine back from the grave.
1) cleaned fuel system - from tank, through carb Twice.
2) changed Air filter
3) swapped exhaust with friends sp500
4) swapped coil and spark plug wire (friend again)
5) A dealer told me it was my cam, I also read this in the forum.
they qouted me $400 to change cam
6) Cam was OK - I took it out and checked with mic. Still good even showed to the dealer
saved $400.
7) Checked all air vents
8) It has set in garage for 1 month now. What's funny is that the dealer called me and told me
that they have a sp500 in the shop with the same problem. They asked me what I found so
that they could fix it. This is the same dealer that was going to charge me $400.

Other symptoms:
1) The spark plug is turning black withing minutes of replacing.
2) The only thing that I haven't checked was the stator

Please send help or flowers. I have bragged on polaris from day one and now I have to keep my
mouth shut. HHHEEEELLLLLLPPPPPP!!!!

 

My friend’s 98 SP500 was doing the same thing.
It turned out to be a bad jet that came with his K&N filter kit. The jet wasn’t one piece, it had an insert in the middle that came loose so it was super rich once you gave it any throttle above idle.
If you have access to your buddies carb do a swap and see how it runs.

 

I too think it is carb or fuel related. Change the fuel filters, check the fuel pump for correct operation, and check for any trash anywhere that might cause fuel not to pass. Also, make sure your muffler is cleaned out. If you haven't done it already, also check the ETC (throttle) adjustment and the choke adjustment. Good luck.

 

Timing chain???

 

I appreciate all the help so far. I will swap carbs with friends sp500 Tomorrow. I have already swapped exhaust but will check fuel pump again. Any advise in fuel pump function and what to look for?

 

Chain appeared OK so did the sprokets. Would it idle ok if timing chain was worn or loose? I did check tensioner while I had the cam out. thanks for help!

 

I had the same symtoms on my 99 500. Tried most of the stuff you did. I sold it before I could fix it but the buyer ended up replacing the cam and rocker arm. He said it runs great now.

 

Thanks for everyone's reply's. I again drained and cleaned the entire fuel system. I put about 1/2 gallon of new fuel and 1/2 bottle of SEA FOAM fuel cleaner in with it. It spit and sputtered for a short time but now seams to be running fine. I ran it hard for about 15 miles last night. Even though I cleaned the Carb several times, I guess I needed something a little better than the usual carb cleaner. Ride On Polaris!!!

I will reply after the weekend. I need to regain my bragging rights. Take no prisoners

 

One week has gone by. No problems! Sea Foam fuel additive seems to work some magic.