I got a 2002 Prairie 650 and I only get 60 miles to a tank full of gas and my top MPH is only 57mph's. I used to get over 80 miles to the tank full and a top speed of 63-65mph. I was sondering if this could be due to my ATV running to rich? If so is it hard to sync the carbs to make the bike run leaner to use less fuel and gain more top end speed??? Any help is appreciated. Thanks

 

I know it probably didn't, but this problem didn't occur AFTER you put the 589s and Lift Kit on did it? Just checking the obvious!

 

happened during the 589's and lift. I wish i could associate the lack of top end and fuel mileage to that, but it used to be better =(

 

Have you checked/adjusted the belt lately? Loose belt=lower top speed. The tire size will throw your speedo/odo off. Bigger diameter tires will make the ODO indicate LESS accumulated miles than you have really travelled and it will indicate lower than actual speed.

 

I jumped on here, as I'm also curious about Syncronizing the carbs... but are you confusing that with rejetting ???

are your plugs reading rich ???

a few things that can effect Mileage...

Tire / wheel weight, & tires rolling resistance... if your reported mileage / speed was with the stock tires compared to the bigger, heavier tires... also the tires bigger O.D. will throw off your top speed ( the speedo reading will be lower than actual ) this also effects your mileage as well, as you are traveling further than your odometer is recording, when computing mileage...

If these readings were with those tires & wheels, then some other things to consider, are air filter cleanliness??? richer jetting, with use of the module ??? belt & clutch condition ( my milage & speed fell off, big time, when my secondary bushings reached the point of disrepair )... if your primary's or secondarie's components or your belt, are becoming worn, it can severly effect shift out, & your overall gear ratio, causing higher rpm's for less speed = more fuel consumption...

If your brakes CV's or bearings, are getting to the point of replacement, it can effect your speed & mileage as you are noting... my ( & others ) front brake pads wore more on one side than the other... this uneven wear, can cause them to hang up slightly... put your quad on a jack, & try spinning each wheel... see if there is more resistance than you'd expect, & investigate if you find any...

as for syncronizing the carbs, what do you really adjust, to equal the vacuume out ???