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Discussion Starter #1
I've got a '03 xc700 and the fuel economy sucks! I know i won't ever change the sled into a really fuel efficient machine but I would like to increase the economy a little and i was told that gearing down a tooth would help, because the engine would not be working as hard, and that is where i am losing most of my economy. Is this true? The sled is basically stock, i have put on a boost bottle to try and clear up the bottom end and i have an inch and a half camoplast track on it. Any feedback would be appreciated. the gearing right now is 25 on the top and 40 on the bottom.
 

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i have an 03 xc500, they say on the xc's with variable exhaust to use premium gas, because it helps get better feul economy, also use synthetic oil. it your using either regular gas or/and oil, switch, and take it into the shop to get the exhaust cleaned out (they dirty up with regular gas). once that is done it should get a little better.

depending on what you call bad feul economy. i get like 120 miles per tank
 

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The 700's are bad on gas there isnt reeally much you can do but have a light thumb, maybe a tempa flow? some reeds?
 

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Discussion Starter #4
ya i don't think there is a whole lot i can do. i get about 90 to 100 miles on a tank riding trails. what is the tempa flow supposed to do?
 

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It refines you jetting. i get 90-100 miles riding trails but i got a hevy thumb. just seen your from Manitoba, Welcome!
 

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what about those ufo fuel savers?? check denniskirk.com
 

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Gearing down is actually going to hurt you milage because the engine will be turning more rpm. The 700 has more than enough lowend torque for the stock gearing.
Basically, you have to accept that fact that any Polaris bigblock twin is a gas hog. Thats just reality.
You could save some MPGs by losing the 1 1/2" lugs on the track and going to a 1" lug, (shorter lugs mean a lighter track, so the engine wont have to work as hard to spin the track) but are you willing to give up the traction that you now have to gain a little fuel economy?
You could also go with milder clutching, that would save some gas too.
Realistically, if you stick with a 700 you are going to have to accept poor fuel economy. Thats a downside of any Polaris bigblock motor.
My brother has an '03 Pro-X 700 and he gets about 11-12 mpg on average, I can routinely pull 16 mpg with my '01 600 XC. The difference is that my 600 is the smallblock 600 which gets a lot better fuel economy.
I guess the bigger question you should be asking yourself is which is more important to you: fuel economy or performance?
 

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If you haven't downsized the mains you should. On my o3 800 ProX the dealer (Wawa Ontario where I bought it on a trip)dropped 2 sizes because they were only getting 90 miles from a tank. I routinely got 13 to 15 MPG and I am over 300 lbs.
 

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Discussion Starter #9
ya, i have not heard about downsizing the mains. i guess that is something to think about. but octane pretty much summed up what i was thinking. and as far as the big question goes i definitly do like the performance!
 

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Drop the mains down to 420. Which will be safe down to -20f. Just don't do any 1 mile+ wot runs. A tempa flow works but I don't like messing with the vacuum it places on the bowls.
What are you running for clutching.
 

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Discussion Starter #11
i am not too sure what i am running right now for my main jet. here in manitoba there would be a few nights in winter where we would go out sledding in -20 ferinheight or -29C. so i don't know if that would be an option. i am running stock clutching, so it is not as though i am losing economy due to a clutch kit.
 

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If you are running the black/green spring it is too strong.

I am using a almond/blue 10-64, red/blue team #719 helix 420 mains and I ride down to -20f. I get 12 mpg at most. With a tempa flow you could gain some milage and be spot on with jetting. Mine is set up for the tempa flo I just don't have one.

The big blocks are thristy but they do get up and go when needed.
 
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