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Discussion Starter · #1 ·
New member here from Minnesota. My ride is a 2004 Sportsman 700 EFI and has just over 1500 miles and 300 hours on it.

I have blown an exhaust socket seal twice. First one was about 3 miles ago, and the new one re-blew right off the header and now it currently sits. I ordered up a Big Gun Evo U full exhaust and plan to install that soon.

My question is, with the EFI, do I need to get an aftermarket tuner? I was hoping to not have to put another $300 into an 18 year old ride. Is there a cheaper solution, or possibly no need at all?

Thanks for any help and appreciate joining the forum!

-Rivy
 

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2008 800 ho efi, 2019 850 SP premium
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I would've spent $6 on a gasket and 15 minutes time to install it and called it a day. But that's just me.
 

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Sounds to me like you need to check the muffler to see if it's plugged
 

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Discussion Starter · #6 ·
Thanks everyone for the replies!

I actually just bit the bullet and purchased the Big Gun EVO U full exhaust system and that seemed to do the trick along with new gasket. The old exhaust system was garbage IMO.

New issue though...is tuning my 2004.5 fuel injectors from the computer. With this new exhaust, my machine is now running rich. That was to be expected, and so I also spent another $250 on the Big Gun Power Box tuner. I wasn't trying to get more power out of my wheeler, just have it run properly at the different RPM ranges.

Problem is, the 2004.5 injector cables that connect to the computer (where I plug in the tuner) are not the correct shape or size as the tuner. The tuner itself said for years 2005 - 2008, but I was going under the assumption this would also cover the original Twin EFI 2004.5 model I have.

My new question is, what options do I have? I only have about a week in which to return the tuner, but I'm hoping I can still make it work. I've spent too much time trying to find alternative tuners and cable adapters for my injector cables, but can't seem to find anything.

Appreciate all the help you can provide!

-Rivy
 

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No - a 'tuner' is not needed - it will require numerous starts, but the EFI will adjust itself to the change in engine air flow - it will not be immediate, but within about 20 cold starts it should run normally again.
 

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Discussion Starter · #8 ·
No - a 'tuner' is not needed - it will require numerous starts, but the EFI will adjust itself to the change in engine air flow - it will not be immediate, but within about 20 cold starts it should run normally again.
Thanks latebird for the advice!

I talked with a couple shops in my area and I was told that the EFIs in these older models won't 'learn' air flow and that it wasn't until Polaris changed their EFI systems around 2017, where the computers could make those adjustments?

And to no surprise, when I reached out to Big Gun, they also recommended a tuner.
 

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Well, it's true that the EFI on ATV's is not as complex as the EFI on cars and other automotive products, but it's also true that more R&D was done on automotive products and while ATV EFI is relatively simple, not very refined and subject to failure due to heat, vibration, shock, electrical system surge and even external magnetic field disruption (riding around or under high tension power transmission lines has been known to scramble the ECU's of all brands of power sports EFI controlled products). Consider this: electro magnetic field discharge (EMF) could potentially knock out the power grid, disable all vehicles in the area of the discharge, erase computer hard drives and damage the SIM cards of wireless communication devices. It's why I race with carburetted engines and have at least one personal transportation vehicle that does not rely of EFI to control the fuel mixture required for an engine to run efficiently.

Does Big Gun offer to correctly program the tuner after you install it? NO - they may offer suggestions to tune your individual configuration, but the final setting is the consumer responsibility. In California the sale of after market exhaust systems and tuners is banned. Just having a tuner on a vehicle in CA subjects the owner to fines and confiscation of the vehicle the device is installed on.
 

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Discussion Starter · #10 ·
Thanks again latebird!

Once I purchased the tuner, I was planning to take full responsibility of tuning my wheeler using their tuner. They even have videos on their website showing how to tune various RPM ranges.

But like I mentioned earlier, my cables from FIs to computer are not the same in my 2004.5 year model as the 2005 - 2008 models of same motor. That is why I'm looking for advice, like you've given, or if other people have had similar experiences with similar wheeler as mine, and what they have done to remedy the issue.
 

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I have a degree in electronics and understand EFI - it's also the reason I refuse to work on EFI systems - it takes about $10,000 in diagnostic and programming equipment ot correct even minor problems and unlike automotive products, the recreational vehicle manufacturers all use proprietary connections and software. You can't fix a Polaris with Honda software and if you Polaris is over ten years old, good luck in finding a dealer with the equipment to correct a problem. The projected vehicle life = the warranty period - extended warranty is just an insurance policy that leaves most buyers with remorse when they discover the product they purchased the coverage on has needed parts discontinued by the manufacturer and there is nor coverage for inability to obtain required replacement parts, so they jave a useless vehicle with useless coverage. It's the sad political world we live in where politics over rule responsibility and common sense.
 
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