Just a thought, did you check the reeds? If they hang open even a little, it will play havock with the low end. When the rpm's come up, it is less noticable. Make sure they are tight to the reed block, they should snap when you lift them off and let them go. Check for split reed tips and chips or cracks too.
Polaris 2000 XCSP 500 Very Thirsty
- Thread starter tutone
- Start date
I am at my cabin now (getting ready to go ride tomorrow, yea!) and pulled out my 2000 Polaris service manual. Specs for the 500 VES motor, with TM 38 carb's are as follows:
Main jet - 420, with #3 clip postion. Good for -20 to +10 and 0-900 feet altitude
Pilot jet - 40
Air screw - 1.5 turns out from seated
Pilot Air jet - .9 (this is the one that screws in the throat on the airbox side)
Looking at the jetting chart, the main jet drops to a 380 for 900-1800 feet and -20 to +10. Depending on where you are altitude-wise, you could easily drop to a 410 or 400 main jet - here in MI my altitude ranges from 700 feet and up and a 410 works fine in a 600. But I don't think that is the problem here.
I'm guessing a little, but with your air screw at 3.5 turns out, your idle mixture is too lean. The troubleshooting section says that backfires are due to a lean mixture. My wife's 2005 600 backfires on occasion just off idle.
Does the problem go away if you put the choke on? If so - mixture needs to be richer.
Regarding the clutching, just to check:
Engagement is 4000 RPM +/- 300
Operating RPM is 8500 +/- 200
If your motor isn't operating in these ranges consistently, then you may have a clutching issue. But I'm betting on the idle circuit. I would try 2 turns out from seated and see if it's any better. 3.5 turns is really out there.....
Good luck!
Main jet - 420, with #3 clip postion. Good for -20 to +10 and 0-900 feet altitude
Pilot jet - 40
Air screw - 1.5 turns out from seated
Pilot Air jet - .9 (this is the one that screws in the throat on the airbox side)
Looking at the jetting chart, the main jet drops to a 380 for 900-1800 feet and -20 to +10. Depending on where you are altitude-wise, you could easily drop to a 410 or 400 main jet - here in MI my altitude ranges from 700 feet and up and a 410 works fine in a 600. But I don't think that is the problem here.
I'm guessing a little, but with your air screw at 3.5 turns out, your idle mixture is too lean. The troubleshooting section says that backfires are due to a lean mixture. My wife's 2005 600 backfires on occasion just off idle.
Does the problem go away if you put the choke on? If so - mixture needs to be richer.
Regarding the clutching, just to check:
Engagement is 4000 RPM +/- 300
Operating RPM is 8500 +/- 200
If your motor isn't operating in these ranges consistently, then you may have a clutching issue. But I'm betting on the idle circuit. I would try 2 turns out from seated and see if it's any better. 3.5 turns is really out there.....
Good luck!
Just a question, but are you blowing throught the jets with compressed air when you clean them? Carbcleaner alone may not clean a pilot jet, you need to visually look throught the jet, it should be open and look like a round hole. DO NOT force anything through it, like a needle or wire. You could open up the hole and then you have no idea what size it is. Compressed air blowing through from the threaded end should clean it out, if you still cant see light through it, replace it. The holes are very small, but the light should come through.
I have a 1999 500 XC
I have a 1999 500 XC..snow checked.. and it seemed to bog a little also at the low end. I never messed with jetting..made sure that both carbs were working together and then added a boost bottle. Took away most of the low end bog..plus when we ride I tend to be "rap'n" it anyways keeping rpm higher most of the time anyways...
BR
I have a 1999 500 XC..snow checked.. and it seemed to bog a little also at the low end. I never messed with jetting..made sure that both carbs were working together and then added a boost bottle. Took away most of the low end bog..plus when we ride I tend to be "rap'n" it anyways keeping rpm higher most of the time anyways...
BR
Well I pulled the carbs again tonight to clean the air screws and guess what I found.....One of the tips has broken off and is jammed in the hole. I used a small Dremel bit (actually a bit that Dentists use) to drill out the brass. I will pick up a new air screw tomorrow and see how it goes. I was sure that I pulled and cleaned them the first time, but now I am not so sure......
You Bet Fredster !
Pays to ask alittle ..... work on it yourself .... and ya learn as you go !
Give the boost bottle a try..only $20 or so and easy to install..Might have to use a cple of cable ties to keep it from rubbing on other parts. They have been known to get a hole in them after a time if you let it vibrate against other parts in the area.
Hope ya get'r done !
BR
Pays to ask alittle ..... work on it yourself .... and ya learn as you go !
Give the boost bottle a try..only $20 or so and easy to install..Might have to use a cple of cable ties to keep it from rubbing on other parts. They have been known to get a hole in them after a time if you let it vibrate against other parts in the area.
Hope ya get'r done !
BR
Problem Solved!
Well I had to order a new air screw, finally got it yesterday. After cleaning and blowing out ever possible orifice in the carbs, I put everything back together. It took a few pulls to get the machine running. It ran terrible, I pulled the sled outside and noticed a very large pool of fuel on the floor. One of the sediment trap hoses had cracked and was dumping fuel all over. I decided to replace both of them. They were both breaking down from the inside. Is this caused by Ethanol in the fuel? After I put the new hoses on, the sled ran great.
Thanks for all your help!
Well I had to order a new air screw, finally got it yesterday. After cleaning and blowing out ever possible orifice in the carbs, I put everything back together. It took a few pulls to get the machine running. It ran terrible, I pulled the sled outside and noticed a very large pool of fuel on the floor. One of the sediment trap hoses had cracked and was dumping fuel all over. I decided to replace both of them. They were both breaking down from the inside. Is this caused by Ethanol in the fuel? After I put the new hoses on, the sled ran great.
Thanks for all your help!
Ya! It is way snappy. No bog at all. I did put the needles back to the center position. I have 410 mains on order, but I dont think I'll put them in.
I need to check gas mileage and oil usage yet, but wow what a difference when the carbs are clean and working like they should!
Thanks again.
I need to check gas mileage and oil usage yet, but wow what a difference when the carbs are clean and working like they should!
Thanks again.