Hey everyone, great forum. I'm a long time lurker, first time poster.

Well, a few weeks ago we got a light snowfall and I took out my 2004.5 Sportsman 500 HO to tear up the lawn a while. It ran normally and everything seemed fine. I had stored it over winter at home with some fuel stabilizer in the tank like I usually do, but this wasn't the first time I had ridden it this year. It always started easily and ran well.

Anyway, after riding around for an hour or so, I parked it in the warm garage and the next day it would not start. It would crank, it had a fair spark, it looked like it was getting fuel (spark plug had gas on it), but it wouldn't fire. It seemed like it wanted to, but all of the sudden it would just backfire. I have taken the gas tank off and shot some carb cleaner into the carb and the jet seems clean, but again it will just crank and then seem like it wants to start for a bit then just keep cranking. I'm going to get a new spark plug as soon as possible, but I'm wondering if anyone else has any ideas as to what the problem might be before I give up and bring to a mechanic. Is it possible that the gaskets are bad and I'm just not getting enough compression? I would think that wouldn't suddenly just happen from one day to the next though. Valves maybe? Is it possible that a valve is stuck open? I'm just about out of ideas...

Also, last summer it started to pull oil into the air box, which is quite annoying since oil isn't cheap. I have read up on the issue (seems to be a common problem) but I still haven't found a solution. I picked up oil and a filter today, so if there's anything special that needs to be done during an oil change I'd like to know.

Thanks in advance guys.

 

Howdy ryanf.....don't know the answer but welcome to the best ATV forum......NoJoke

 

if new plug doesnt fix it , Id say take carb apart and thoroughly clean all the jets and passageways,

 

Check to make sure that the throttle cable hasn't worn enough to cause the throttle safety switch on the throttle to engage. Any more than about 1/8 of an inch of throttle free play and the atv will not start; adjust the free play just down from the thumb throttle, by sliding back the rubber cover and adjusting the cable length.

 

i would check that just to rule it out.

 

I have the same model there was a problem in manufacturing, they pinched the plug wire in between the body and chassis. mine broke down on the trail. read about problem on internet and tried a different wire myself and it fired right up. bought mine new and was 2 years old at the time, dealer changed coil and wire free

 

I have the same year/model as well and had the same problem with the pinched plug wire about 4 years ago. I was miles from anywhere when it quit & wouldn't start, on the hottest day of the summer but that's another story. Remove the front rack & cover and follow the plug wire. Check to see if it's pinched against the frame tightly. You'll be able to see it from under the front cover. If I remember correctly it was clamped to the frame too tight & it wore through which caused it to short out. If that looks like the problem, get a new plug wire & you should be good to go. I didn't clamp the new plug wire to the frame at all, no need to.

 

I agree with checking for pinched plug wire between tank and frame,had several with this problem,enough that a bulletin was issued,some may not show up for awhile! First thing see if there is slack on wire and can move up and down from coil,if feels tight,I would pull wire off coil and inspect. You can use 7mm bulk wire from auto store for replacement,that's what we carried at the shop. Hope this is all that's wrong. OPT