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Discussion Starter #1
Hi all, not too many posts on here but thought I would ask those with more experience for some suggestions. Here is the deal. I bought a used 2006 800 Sportsman from a guy I know. I knew that he had issues with it before and I got a good deal because of it so I didn't go into this blind.

His issues were that the thing would die when it got hot (same common problem so many have noted on this and other forums). He thought it was vapor locking so in an attempt to correct it, he put a heat shield on the exhaust, wrapped the headers, replaced the radiator cap, and put a larger breather hose coming off the fuel tank. He thought this corrected it but still gave me a really good deal.

Anyway, I was hunting and giving the machine a pretty good workout. It gave out on me after a couple hours of riding. I got it started and back to the trailer to take home. I'm sure that it was the fuel pump issue that is so common and that the guy I bought it from thought incorrectly that he had it fixed. No big deal, I replaced the pup, pressure regulator and fuel filter. It runs great (I used the NAPA pump that was recommended).

The reason that I am posting is the other issue that came up right before it quit on me during the hunting trip. Whenever I am climbing an incline, it spills fuel out the breather hose. I was just wondering what some ideas out there to correct it might be or what some issues might be with the ideas that I already have. Here's my thoughts.

1. I could replace the larger hose with the factory size hose but will this truly solve the problem or will it just not spill fuel as rapidly and will it develop breathing issues that the previous owner thought it had.

2. I could not fill the tank as full but I don't like this idea because it would decrease my range on trail rides.

3. Is there some sort of valve that I could put on that would allow it to act as a breather still but not allow fuel to escape?

Anybody have any thoughts or other ideas?
 

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Here's a link to the discussion when I fixed this problem last year...same machine. Using non-alcohol premium fuel and double insulating the tank bottom makes a big difference. When the fuel boils and builds pressure it will blow one of the check valves off and yours is probably lost as mine was. I haven't had any more problems since the fix even on near 100* days and climbs to 13,000+ ft.
Let me know if you need any further explanation of the fix.

http://www.polarisatvforums.com/forums/polaris-sportsman/38726-800-efi-spitting-fuel-out-overflow.html
 

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There should be a couple of one way breather vents in the pod, so it doesn't "spill gas out".

Another thought would be to get a longer piece of vent hose and make a "taller" vent route if possible.

Best of Luck!
 

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Discussion Starter #4
Thanks for the replies everyone. Question for polman though. In the thread that you linked to, what year and model was that fiche for? I looked at the fiche today online and at the dealers to see about getting some parts to fix the vent lines but all that we could find was a 90 degree elbow and a hose. No check valves or anything else like in the pic you posted.

Any ideas for a check valve? I'll look into the chainsaw ones but probably too small for the vent hose that I have right now.
 

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Thanks for the replies everyone. Question for polman though. In the thread that you linked to, what year and model was that fiche for? I looked at the fiche today online and at the dealers to see about getting some parts to fix the vent lines but all that we could find was a 90 degree elbow and a hose. No check valves or anything else like in the pic you posted.

Any ideas for a check valve? I'll look into the chainsaw ones but probably too small for the vent hose that I have right now.
If you reread the old post carefully I mentioned that the microfiche was for the 2007 800 EFI. My personal machine is a 2006 800 EFI like yours. I've learned over the years that Polaris often changes things mid year during production and the microfiche sometimes don't match exactly. If something in the microfiche doesn't match with what I'm seeing on a machine I'm currently working on, I refer to prior and subsequent years diagrams to figure it out. That's how I originally found the problem...or...maybe Polaris made an improvement starting with the 2007 year model once they discovered they had a problem with fuel spitting out the vent.
I'm not sure how the PO put larger line on the vent but that's not the solution. If you'll insulate the tank bottom with Heatshield insulation from any auto parts store or available online, use good fuel and install check valves it will fix the problem. The Polaris check valves are pretty tiny and not very secure in the lines is why I went with larger ones for a Stihl chain saw. You could use any check valves. Those on the bottom of carburated machines for the overflow on the bowl may fit your existing hose. They should be easily found too.

**IMPORTANT**They MUST be in the configuration shown...the valve on the main end allows air to flow IN so you don't create a vacuum in the tank as fuel is used but it prevents fuel from escaping. This one just lays in the pod. The one off the T goes OUT allowing excess pressure to escape. The OUT line runs under the handlebars and down into the steering stem.
Sorry to be so long-winded but let me know if I'm not being clear on the fix.
 

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Discussion Starter #6 (Edited)
Thanks again for the response. I checked later year fiches thinking that it was a design change but they showed the same as 2006. I'll check again and see what I can find.

Edit: I checked and it's exactly as you said. I'll see what I can come up with for parts. Thanks again. Can you tell me what size hose the vent tubing is? Probably a lot cheaper to buy some fuel line from the parts store than get parts from Polaris and the Ts and elbows I can just get at Home Depot. Then I'll try the Stihl check valves as you suggested.
 

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The OEM line is pretty small. Maybe 1/8" ID or something. You should be able to look at the tank fitting and tell unless the PO changed it.
 

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Discussion Starter #8
Yep, the PO replaced it with a brass elbow to put the bigger hose on. It's like 3/8" line now. :mad:
 

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Well, you could just use an adapter nipple fitting to get it back down to a hose size that available check valves will fit.
 

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Discussion Starter #10
Yep, that's what I plan on doing. That's why I was asking the original size. Thanks for all the help.
 

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Ok, but I'm not positive about the OEM size so I'd get the valves first and match up hose and fittings from there.
Good luck and let us know how it works out.
Oh yeah, don't forget to insulate the tank bottom if its not already as that makes a huge difference in how hot the fuel gets and therefore the amount of pressure created in the tank.
 

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Discussion Starter #12
Ok, but I'm not positive about the OEM size so I'd get the valves first and match up hose and fittings from there.
Good luck and let us know how it works out.
That's what I'll do. I'll base the hose size off of the check valves that I get. I'll post up how it works out. Might be next year though because riding season is coming to a close real quick here in AK.

yeah, don't forget to insulate the tank bottom if its not already as that makes a huge difference in how hot the fuel gets and therefore the amount of pressure created in the tank.
He already had the whole bottom half of the tank wrapped in foil. It looked good to me so I didn't mess with it but I might redo it next time it's apart just for insurance. He also wrapped the headers. I'm thinking about taking the wrap off though and maybe getting them ceramic coated over the winter.
 

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For Polman500 - I have an issue with a split vent tube (it's just getting old), just above the tank, and it is leaking fuel when going uphill. I took the pod apart and the vent tube went down inside the steering column, which I pulled out. No check valve on the end. I have read the other posts concerning the tube and will be replacing the tube and adding a check valve, but trying to get the tube back down the steering column seems to be nearly impossible without taking the handlebars off. Is there a problem with using a shorter tube and terminating it inside the pod?
 

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For Polman500 - I have an issue with a split vent tube (it's just getting old), just above the tank, and it is leaking fuel when going uphill. I took the pod apart and the vent tube went down inside the steering column, which I pulled out. No check valve on the end. I have read the other posts concerning the tube and will be replacing the tube and adding a check valve, but trying to get the tube back down the steering column seems to be nearly impossible without taking the handlebars off. Is there a problem with using a shorter tube and terminating it inside the pod?
Is the tubing still in one piece? I would suggest taping the new tubing to the end of the old and pull it up through to fish it up there.
 

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Opps, just re-read your text and saw that you had already pulled the old tubing out, can you tape the new tubing to a coat hanger and fish it up there?
 

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The old tube is still in one piece - the split is about 1" lengthwise just above the fuel tank and right under the pod. Are you suggesting running the new tubing up from the bottom of the steering column? I have already pulled the old tubing out of the steering column - didn't realize it was quite so long, and now have it directed down through a vacant area in the pod, out the bottom. I'm probably making this way harder than it really needs to be!
 

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You could leave it run down out of the pod and under the plastics but I wouldn't leave it inside the pod. If you get some overflow during hot weather you don't need fuel blowing out into the pod as there could possibly be stray voltage from a loose or frayed wire....BOOM!... LOL It'd be better to get it back in the steering shaft if possible perhaps by using a piece of wire or something to guide it in under the bars.
 

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Here's how its supposed to be set up. The #18 check valve on the top is the intake to allow air to flow in if needed and just terminates in the pod. The #18 valve on the left of the picture has the hose on it that goes down the steering stem and is the outflow for when the fuel gets hot and tries to push out. It may burp a little fuel sometimes and so needs to go down the stem away from any sources of ignition.

 
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