Poor gas mileage on rebuilt Polaris Fusion 600

Hoosier

Well-known member
I was in northern wisconsin and the Western UP riding the past four days. This is the first time I've put any significant mileage on the sled since it was rebuilt. Put about 1,000 mileage on, and gas mileage was consistently low - 7-8 MPGs. I cleaned the powervalves one night, but they weren't that bad. I am going to call the mechanic who rebuilt it to see if he changed the jets or something, but I thought I'd post here also. Track tension seemed fine. I was running a brand-new Polaris belt that seemed to sit where it is supposed to on the clutches. Other guys in the group did fine on gas. Two of the guys have 600 CFIs, and they were consistently getting 14-15 MPGs. The Cat in our group with 10,000 + miles on an EFI 700 did fine on gas, as did a 600 Carbed IQ, which is the same engine and set-up as my Fusion. I used 20-25% more gas than either of those any stop (if they put in 6 gallons, I would have to put in 8 or so).

On the plus side, the mechanic who rebuilt the engine also re-shimmed the clutch (a previous dealer in Indiana had done this), and the 1,000 miles is a new record for that sled on a belt. I'm crossing my fingers that the clutch is now properly set-up.
 

6mile

Member
Did you check the plugs to verify that both sides are are burning the same?

Check the choke plungers on the carbs. One could not be seated properly or out of adjustment allowing it run on the rich side.
 

Hoosier

Well-known member
I replaced the plugs. The old ones had a lot of gunk on them, but I think that was because it was the first time I had the sled out for the year and it was fogged and I put sea foam in the tank. I didn't do anything with the carbs.
 

motor_slut

New member
Things to check

Plugs- are they black? If so jet it down. The stock jetting is too fat for most areas of the UP.
Bearings- did you grease them? if not give them a shot of love
Chaincase- did you change the fluid and check the tension? Overly tight chains can cause serious issues low fluid is even worse.
Track- too tight is not good and Polaris' really like to have a looser track unless they have an M-10.
Idlers- any bearings going bad on the idler/bogey wheels will cause issues.
Clutches- any signs of stuck weights or bad roller/bushings should be fixed. A worn belt can cause issues too.
 

Hoosier

Well-known member
I talked to the mechanic at the dealership that rebuilt the engine. From all accounts, he is a very skilled mechanic. The engine was rebuilt late last Feb. He didn't remember whether he changed the jetting but said they often do on a rebuild. He said they would have included it on the service ticket. It wasn't on the service ticket, but I have a feeling that he did change them. That seems to make the most sense. I will check the plugs, but we may be going to ride in South Dakota in a few weeks, if so I'll be rejetting and can see for sure what jets are in there....
 

ezra

Well-known member
I also feel your pain and am looking for a bigger can to carry on the back of my M1000 just to make it to a gas station
 
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