I am curious what kind of gas mileage people are getting with their 700s. I know the type of riding has a big effect on it. Most of my riding is on gravel roads and logging roads and trails in the creek bottoms and such. It seems like I am getting about 10-12 miles per gallon, but this is with a lot of time in low range.

 

that sounds like incredicly good milage in low range

 

I have a buddy that has a 700 just like yours that has a bigfoot kit ,(wheels and tires) on it and he says that it really likes gas a lot, don't really know any numbers, but he had a sp 500 before and he says that it uses quite a bit more than it, but it is not broke in good yet so it may get better after he gets it broke in.[img]i/expressions/face-icon-small-cool.gif[/img]

 

A buddy we ride with has gotten 56 miles before going to reserve on a tank a couple of times. Add another 10 for reserve, I'd say 66 miles is probably a good idea of what you can expect. He does like to play with the throttle, so a slower rider could probably do a little better. Riding around in low will affect your mileage too. I only use mine when needed. No need to put any extra strain on the motor.

 

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Greetings from Central B.C. I just bought a 700 Polaris and the milage is somewhat hard to swallow.. Only have about 100 miles on it so far but the best I have done is 44 miles and the tank is just about empty.. I hope it gets better as it breaks in.. I was hoping for at least 65 miles from a tank of fuel before going to reserve.. It sure does not keep up to my Rubicon on the milage aspect.. I can get about 105 KLMs to a 3.2 Imperial gallon tank on the Rubicon. The Polaris has a 3.93 Imperial Gallon tank or 17.9 liters which is about 4.7 gallons US and at 44 miles to a tank it is lacking. I did expect a little more fuel usage but figured the larger tank in the Polaris would handel that and keep up to the honda. The type of riding is pretty general from bush roads, trails, swamps, rocks & stumps and just about every thing in between in a days ride. I think I may have to tow a fuel truck on behind. We generally go pretty far back into the bush and there is no fuel or no anything back there for weeks. Nothing but moose, grizzleys and Indians and none of them have aby fuel either. As it breaks in I will post my milage on this forum for anyone interested.

Cheers!

 

This must be one big reason why there is a 34mm carb on the twin and not a 40mm carb like the 500HO has. Has anybody tried jetting it down a size or two?

Buddy P

 

Carb size vs engine cc's is greater on the 700 then the 500 as it is now. Even though the carb is smaller, the pistons travel together but are on different strokes. This means the carb feeds only 1 cylinder at a time. CC's fed per millimeter of carb. 500HO=12.5, 700=10.3, 600=8.8. Gas milage has very little to do with the carb size. Even if I were to put on a 40mm from the 500 on my 600, once properly jetted and adjusted, it will feed the same amount of fuel as the original 34mm. Maybe slightly more due to a less restrictive opening but not worth mentioning and performance will be the same unless the Polaris engineers screwed up and undersized it.

 

Yes the carb size vs cc is greater but for every cycle the 500HO makes the 6 and 7 hundo are firing twice when the single cylinder fires once. Carb size will affect fuel delivery as well. Larger carb = more air velocity. More air velocity leans out fuel mixture therefore you need to increase fuel flow. The more air that can be entered into the motor the more power it will make but you sacrifice in fuel usage.

I guess I was just curious if anyone tried to lean it out any and if they encountered any detonation and if so how much leaner did you go to get there.

Buddy P

 

Unless the Polaris engineers undersized the carb so it causes a restriction, you cannot increase the air velocity by simply installing a bigger carb. The only way to do so is by turbo or supercharger which will force the mixture in. There are other limitations apart from the carb size, otherwise everyone would have 100mm carbs and getting major HP's from there machine. I do not see the difference in your explanation between the 500 single and the twins regarding cc's/carb size. In the case of the twins, the carb is only supplying 1/2 of the overall cc's at any given time and therfor supplying 1/2 the overall cc's with the fuel/air mixture at any given time. Take the 700 vs 600 as an example. Exact same carbs apart from a different pilot jet and needle jet, they are identical, even the main jet is the same. If your thinking is correct, then the 600 carb is oversized or the 700 could benift from a slightly larger less restrictive carb. I will assume the 700 has the correct carb size since it was designed for the 700 in 02.

 

Well of course if it's doesn't cause restriction you won't see an increase but I will tell you that there is no vehicle anywhere with a factory supplied carb that does not cause a restriction. Sure there is a point where you can only go so big. Try this... take a very small diameter straw and a larger diameter straw. Suck through the small one as hard as you can then suck through the big one. After doing this try telling me that you were able to pull the same amount of air per second though each straw... that would be an untrue statment. But would be true if the smallest straw allowed your maximum pull of air through it. If the size of the carb didn't matter then I wouldn't have spent $1100 on a set of 48mm carbs for my drag snowmobile and would've left the stock 38's on it. Fact is there is no way I would've seen 250hp on the dyno with the stock 38's.

As far as the 500 single vs twin's, all I was referring to there was that even with the 34mm on the twin your seeing worse milage because the twin motor is firing twice per every full cycle where as the 500 obviously only fires once per every full cycle. So by using your math of 500HO=12.5, 700=10.3, 600=8.8, for every full cycle the 500 feeds 12.5, the 600 = 16.6 and 700 = 20.6. That translates to more fuel per full cycle that the motor goes through (which equal's 2 revolutions). Your right as for as the carb only supplying 1/2 of the overall cc's at any given time... but does it every revolution with the twin whereas the single cylinder does it once every 2 revolutions..... I didn't mean to refer that portion of my statement to actual carb size.

Needle jet setting will make a difference in fuel consumption as well since it affect midrange motor operation the most. And that is where most people ride at.

Buddy P