I'm new to the board but have been reading a lot of the threads. I've got a problem with my 2004 SP 500 HO. I had a HotSeatPerformance kit installed with the pipe, K&N filter and clutch kit. Actually, I had it installed on both of my 500's. One runs great but the other one seems to be running rich (I am assuming) Hot Seat says not to change the main jets on the 500 HO. I called them already. So I believe the stock jets are still in place. I had the dealer install these. My problem is that I have lost about 5 or 6 hundred rpm. It will only top out at about 5500 rpm and is not nearly as responsive as the other 500. I have adjusted the needle jet both up and down and no help. I'm assuming it is rich because the plug rim is really black. I thought with the pipe and filter it would run leaner. Any help would be greatly appreciated. I know this is probably a repeated question but I really need help on this.

 

Did they recommend adjusting the air/fuel screw at all? Another area I would look at is to see if the secondary clutch was wound correctly

 

welcome ot the forums... good luck with your sportsman... how are your valves

 

It is possible your problem is unrelated to your upgrades?
If it is running rich a possible cause is your needle valve that controls the gas supply to the carb. It is common for the valves to leak by due to dirt or the valve is grooved. It might be possible to test this by starting the engine let it warm up and shut off the gas via the on off res switch. Let it idle for 30 secs to burn off excess gas in the float chamber then run it. Open it up and see if the performance comes back even though it will be for a short time only until the you run out of fuel in the float bowl.
Just a thought.

 

Good reading. You guys are better at this then me for sure. Having said that, could his choke be the problem somehow? Sounds choked?

 

Man, you guys are fast. I'm not used to people responding so fast. First, no they didn't mention anything about adjusting the air/fuel. They only said that sometimes they have to adjust the needle valve. And I never thought about the clutch. But I only have about 800 miles on it. We just bought them a couple of months ago. I'm just hoping I can get this fixed without having to take it back to the dealer. They have a good mechanic, but I'd like to learn how to do this stuff myself. I been a mechanic most of my life but not on these. I figure if I'm gonna ride I'm gonna have to learn how to troubleshoot and fix it. I'm just not so familiar with atv's. It seems like I keep losing peak rpm. Now it's down to about 5500, so it is getting worse. I guess it's possible the belt may be part of the problem? I do ride it a tad on the aggresive side. I did adjust the needle valve. It was in the third down slot. I moved it to the second down and it wouldn't run so I put it in the fourth down and it runs but that is when my rpm dropped to about 5500. And the temp outside was about 55 or 60. But the problem seems to be more with the full throttle position than anywhere else.

 

You did say the plug was black which is an indication of a mixture that is too rich. With the mods you made you should have had to install a larger main jet for full throttle and lift the needle for mid throttle. Of course doing this will make it richer and it seems you are too rich already. I would try cleaning the plug then take it for a run at full throttle then stop and shut off the engine immediately. Remove the plug and check the color . If the plug is black it's too rich and grey or white it's too lean. Now do the same for mid throttle position. This should give you an indication of how it is running. Let us know how this works out and we'll take it from there.

 

With the HPD Exhaust I have on my 500, I had to install a 160 main jet and turn the air/fuel screw 2 turns out from seated. Nothing with the needle jet. I am not sure how the HPD exhaust compares to the HSP exhaust (other than they arre both full systems), but this may give you a place to start

 

OK. Lucky I live out in the country and have some room to wind it out...lol. Question. Should the drive clutch be fairly easy to move in and out with your hands? Just wondering because this one is a little sticky. I did take it up the road at wot. Weird thing is, it levels out at about 5500 rpm for about 5o yards and then it went to about 6200 before I let off. Why the leveling and then rise again in rpm? I left the needle at the fourth clip. I was wondering if maybe the drive clutch is simply holding it back or maybe the carb is starting to lean or richen? And thanks for the help in this. I WILL get it going the way I want it eventually...lol.