2000 Polaris Sportsman 500 issues

[Christian Brindle]

I have a 2000 Polaris Sportsman 500. A year or so ago we got it running after replacing the kill switch. It ran great but after some use for a couple months it got a flat tire and for some reason we just forgot about it and it sat for some time. Before it sat i replaced the gas cap, fuel filter, fuel pump, petcock, battery, starter relay, oil and oil filter. I recently went to start it and it started so quickly and without choke or throttle but the ATV wouldn't move till about 1/4 throttle and it wasn't really a smooth ride until 1/2 throttle. it also would bog out randomly after you came to a stop and sounded like it was getting too much fuel. I cleaned the carb and adjusted the air/fuel screw to 1 3/4 turns out.  I also messed with the idle and the throttle cable adjuster up on the handlebars. It's safe to say it now runs worse than when i started working on it 2 days ago. It takes more effort to get started and bogs out idling after about 30 seconds. I tried adjusting the idle but every time i do it'll get to a sweet spot but after driving it down the driveway and back the idle will go up and down to the point where i can't put it in gear because the gears will grind. Any thoughts or ideas would be greatly appreciated. Thanks

[Frank Angerano]

I would try to set that air/fuel screw to 2-1/4 turns out from a snug tight position and see how that goes. 

And also be sure you cleaned the carb properly and put a new plug in as well.   

 

[JacobSlabach]

I would do the same as what @Frank Angerano  said with the air screw.  I have an 04 sportsman 500 that I had to replace the carb on so I will be working through the same issues of adjustments.  as for not getting moving by 1/4 throttle, sounds like a worn out belt to me.  mine does the same thing, but I dont worry with it cause it still runs good- just doesn't get moving as soon on the throttle.  I also have a kawasaki bayou that has a Chinese carb on it and it would start cold or run right ever till I turned the air screw out about 2-3 turns past what the manual called for...  runs flawless now, easy to start in any weather condition...  It would also bog out if I had it pegged at high speeds- not now- the thing is a speed demon now.😎🤘

[AlanN]

Christian,

Reading your description, I believe you are talking a fuel problem. If so, Part A is what has worked for me on many vehicles and tractors.  I help a lot of older farmers and work on their old tractors and things that sit a lot. Also help locals with mechanical issues.

Part A:

Put some Seafoam in the fuel and run it. Old fuel with alcohol is hard on these carbs.  The corrosion will partially plug up the  circuits, especially the  low speed one.

If you are going to let it sit, turn off the  fuel and run the carb out before storing.

I used to own a 2000 500 also. I had it act similar one time when I forgot to empty the carb.  I put in 1 gallon of fresh fuel with 6 ounces (rich) of seafoam and let it run at a high idle for almost an hour.

I could hear the  engine "clean up" every so often and the  engine speed would raise. I would readjust the idle speed and let it keep running.  I then put one more ounce of seafoam in the  tank and filled it.

I always put one ounce of seafoam in every tank after that and never had another problem. It would start in any weather almost faster than I could get my thumb of the  switch.

Part B:

If it actually takes 1/4+ throttle to move and it is not because of the engine performance itself, Like those before, it could be the  belt and or clutch have an issue.

 

Wish you the  best in getting your ride back together!

[Guest]

When i get an older Sportsman 500 in the shop with what appears to be carburetor problems,believe it or not,first thing i check is the camshaft. Pop the valve cap off,remove the rockers and verify the cam lobes and followers are in good shape. Adjust the valves while your in there.It only takes about 30 minutes to check and then you can rule it out. I can't tell you how many cams I've replaced over the years on the 425s and 500s. A bad cam cam will act like carburetor problems and you will end up chasing your tail because of it. After that get a manual and get the carburetor up to spec. Fresh fuel and clean fuel system is a must. Make sure the air box lid and gasket is in place. Without the lid and gasket they won't run properly. This is not a diagnosis,just  my opinion. You should first verify proper spark (at the correct time), good compression and clean fuel supply. Try to make sure its actually a carburetor/fuel system problem and not an ignition problem or something else.

[Frank Angerano]

Theses are all very good points and super helpful.  Especially the members that have this particular bike.  It’s great to see everyone’s different opinion on the problem/solution. From fuel/air, valves,belts which all are valid and possible.

@Christian Brindle please let us know how you make out with this problem.    I’m curious to see how this turns out and what the problem is/was. 

[JacobSlabach]

@AlanN   👈 what he said!  welcome to the forum!

[JacobSlabach]

6 hours ago, Kent Mettler said:

When i get an older Sportsman 500 in the shop with what appears to be carburetor problems,believe it or not,first thing i check is the camshaft. Pop the valve cap off,remove the rockers and verify the cam lobes and followers are in good shape. Adjust the valves while your in there.It only takes about 30 minutes to check and then you can rule it out. I can't tell you how many cams I've replaced over the years on the 425s and 500s. A bad cam cam will act like carburetor problems and you will end up chasing your tail because of it. After that get a manual and get the carburetor up to spec. Fresh fuel and clean fuel system is a must. Make sure the air box lid and gasket is in place. Without the lid and gasket they won't run properly. This is not a diagnosis,just  my opinion. You should first verify proper spark (at the correct time), good compression and clean fuel supply. Try to make sure its actually a carburetor/fuel system problem and not an ignition problem or something else.

thanks for the input!  never heard this before.  I would say that personally, I would check the easier stuff first-  (spark, compression, starter, gas, carb(in that order)), My dad is a general contractor and he always says check the easiest thing first (say a bulb instead of the light fixture) an example:  my bayou just randomly wouldnt start- checked spark, then compression, gas supply and made sure my valve was on, checked the kill switch, then replaced to sp.  I was positive the sp wasnt the issue because it was maybe a few weeks old- I was wrong.  I am not saying it isnt the cam on your bike, I just saying its a shame to pull the guts out of the head and it was a spark plug all along..

P.S.  lol to see the whole story behind my bayou, look up my thread '97 Kawasaki Bayou Runs Bad'

[Frank Angerano]

That was a great thread on the runs bad bayou! And well said Jacob. Start with the easy stuff first.  It does not cost a thing and eliminates any of that ahead of the heavy stuff.  

[Christian Brindle]

Thanks for all of the helpful tips and ideas! I wish i could work on it right now but the weather isn't agreeing with me (Wish i had a nice garage lol). I'll definitely go at it once this rain lets up. I've messed with the carb so much but from what I've read off this forum i'll tear it down again and correct the air/fuel screw and also run seafoam afterwards. If it still runs the way it does right now ill correct the timing and checks the cams! I'll also check the belts while i'm at it.

[Guest]

I wasn't saying tear the top end off or anything like that. I always adjust valves as part of a complete tune up on any ATV or whatever i'm working on. On these models while your adjusting valves it takes an extra 5 minutes to check the cam and followers by simply removing four bolts and lifting off the followers. You don't have to remove the cam or cam chain or mess with the cam timing or anything. Then you can at least rule out the cam as being a possible issue. Flat or rounded off cams were somewhat of a problem on these engines in the past. That's the only reason i mentioned it. Machines would not accelerate,no power, etc, but they will idle and sound perfect,no ticking or rattling to speak of.  Again this , and everything else mentioned in the post , is just part of a thorough tune up,no major surgery here. I also make it a point to check the charging system during a tune up. An overcharge condition can be very easily mistaken for carburetor problems or ignition problems. A big wasp nest in the muffler will cause lost of head scratching too!! Like i said earlier i'm not saying this is whats wrong with your bike for sure, just something to keep in mind while your tuning.

[JacobSlabach]

On 2/17/2019 at 10:47 PM, Kent Mettler said:

I wasn't saying tear the top end off or anything like that. I always adjust valves as part of a complete tune up on any ATV or whatever i'm working on. On these models while your adjusting valves it takes an extra 5 minutes to check the cam and followers by simply removing four bolts and lifting off the followers. You don't have to remove the cam or cam chain or mess with the cam timing or anything. Then you can at least rule out the cam as being a possible issue. Flat or rounded off cams were somewhat of a problem on these engines in the past. That's the only reason i mentioned it. Machines would not accelerate,no power, etc, but they will idle and sound perfect,no ticking or rattling to speak of.  Again this , and everything else mentioned in the post , is just part of a thorough tune up,no major surgery here. I also make it a point to check the charging system during a tune up. An overcharge condition can be very easily mistaken for carburetor problems or ignition problems. A big wasp nest in the muffler will cause lost of head scratching too!! Like i said earlier i'm not saying this is whats wrong with your bike for sure, just something to keep in mind while your tuning.

didint mean to say dont do this!  I was just making a point that it saves a lot of butt pain to check the easy stuff first like sp, s, gas, etc (lol dont want to repeat my earlier post )

[Christian Brindle]

@JacobSlabach @Kent Mettler  Yeah i figured lol had me a little confused for a second

[Christian Brindle]

@Frank Angerano @AlanN @JacobSlabach  I've posted a new forum on what i have done to the atv. Please check it out as i could still use y'alls input. Thanks

 

[Frank Angerano]

I looked I responded to it unless i am missing something? 

It was on the cams ? 

[Christian Brindle]

@Frank Angerano I'm sorry, i didn't realize you were the person who commented. i was just trying to fill this old forum in with whats going on now. Thanks for you're input

[Frank Angerano]

No worries brother. Just pay attention to what your buying and like I said if the machine is all stock then go with the oem parts.   Anything else you need Quadcrazy is here to help you along.   

[Christian Brindle]

@Frank Angerano  So i got the new cam and everything and put it all in. but the timing mark on the chain won't line up with the timing mark on the flywheel.... i put it all back together to see how it would act and it turns over fine with no throttle but when any throttle is given is sputters when trying to turn over. i then took the carb off and it acts how it did with the throttle opened. I'm guessing this is because the timing is off but i don't know how to get the chain back in line with the flywheel timing mark. 

I tried to explain that as best as i could, sorry if it's confusing.

[Frank Angerano]

Hey brother sorry been busy. Getting the timing right is a bit of a bi***. It’s a matter of getting that chain in the right spot because when u tighten the chain tensioner it moves the cam spot back a bit.  It’s a matter of touch so move it a bit forward on the sprocket and tighten the tensioner and see if it lines up if not go a tooth further.  

[Christian Brindle]

@Frank Angerano Thanks man, i'm about to go try and correct it now. and you're right, it is a bit of a bi*** lol

[Christian Brindle]

@Frank Angerano So i tried fixing the problem, and thought i did. So i put it back together and the problem is still occuring. It just has problems trying to turn over and i know i could cause a lot of damage if i continued trying to turn it over. Here's a video of the way its acting and the sounds its making. Thanks 

https://www.youtube.com/watch?v=lAWkPKTye3U&feature=youtu.be

 

[Frank Angerano]

I can’t see the video for some reason. Can you explain what’s going on ?

[Christian Brindle]

@Frank Angerano 

Here's the new link. Sorry about that

[Frank Angerano]

Wow ok, so two things come to mind.
1. The compression release, is it working properly. 
2. The timing is 180 deg out. 
Are you sure you set the timing correctly?

If you pull the spark plug out and crank the engine how does it act, any binding? 
 

[Christian Brindle]

I haven't tried electric starting it with the spark plug out but when i pull start it, it is easy to pull then it has a rough spot where its harder to pull. I thought i had the timing correct but i see not now. I do need to make sure the compression release is correctly installed though now that you mention it

[Christian Brindle]

On 10/19/2019 at 8:53 PM, Frank Angerano said:

Wow ok, so two things come to mind.
1. The compression release, is it working properly. 
2. The timing is 180 deg out. 
Are you sure you set the timing correctly?

If you pull the spark plug out and crank the engine how does it act, any binding? 
 

Thanks man, the compression release was the problem. Took it out and reinstalled it and it no longer has that problem. Good thing i took care of it because the ball was starting to wear the exhaust rocker, no scoring or anything just a slight color change from rubbing. Thanks again, hopefully there will be no other problems

[Frank Angerano]

That’s great, nice work. Ride safe. 

[Steven Turner]

Admittedly, I didn’t read every response prior to posting this but hopefully someone mentioned the CV carb is fully reliant on steady unrestricted vacuum. Any obstruction to that vacuum circuit can cause those symptoms. I’ve also had issues with the throttle cable routing being the cause. Ensure the routing is exactly as intended and cables are well lubricated. Polaris makes a good bike, just picky as hell. Get it dialed in, and she’ll run until she doesn’t. LOL

[Frank Angerano]

It’s a good point @Steven Turner but fortunately it was the compression release. CV carbs must be properly cleaned including the vacuum ports so def a good point.  

[Christian Brindle]

@Steven Turner Thanks for the input but as @Frank Angerano stated, it was the compression release and now its running AMAZING! Don't need any throttle nor choke and it starts in a fraction of a second. Thanks again to everyone who contributed to this forum yall were so much help