What makes the Yamaha Twin such a gas hog?

Zaj 243

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Joined
Dec 4, 2007
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36
Location
New York
Just as title states, why do they like their fuel so much? Went riding thursday, my buddy on his '08 800xp ski-doo did the 60 miles on 3.8 gallons, my sx500r used 7.2 gallons!! I know its normal, but is there anything I can do to improve mileage? I just picked up another 500 twin yami, and have the engine apart, anything I can do, or tricks people have done to help the twins run more efficiently? I am planning on making sure the case half is matched to the cylinders, match exhaust ports to the y-pipe, and setting proper squish clearance on the heads (re-cutting the domes if ccv ends up too high). I'm trying Boyesen reeds on this model, and might make some reed spacers to see how they react with the twin. Another option is swapping carbs. I have a complete setup of 34mm flatslide kehein's off a pro-x440, thinking the slightly smaller bore might pick up the velocity of the intake, making it more efficient on trail riding. Open to ideas and comments!
 
wow !last long trip with my 94 vmax 600 i kept track and used 6 u.s. gallons for 70 miles.last time i used the sled i went maybe 50 miles and used the whole tank!ive traced mine to the clutches,the primary was shot so i bought a 108 exp and am waitng on new ramps for the secondary on monday so i expect the milage to improve back to 10 plus mpg.i usually get between 95 to 110 miles per tank if i dont hotdog it.i would say 12 to 13 mpg is about right for my sled on a good day.i run my track fairly loose to cut down on drag also.my sled is dragging around a 230 lbs guy so im not too bummed out with the milage atall.plastic or composite ski,s help a lot too and well tuned carbs also.be thankful you dont ride with a etec or my buddys 05 rs vector which get in the 20 plus,lol,you,d really be bummed out! i think one of those will be for me soon.
 
Yeah i got better mileage on the way back, I was babying the throttle as much as possible and got around 10 or so mpg. 8-8.5 is the norm. My SRX600 i could pound as hard as i wanted and never go below 10mpg, usually it was around 13! My clutches are in good shape, and have a clutch kit installed on my 500. I'm curious to see what the mileage is on the new 500 i picked up with stock clutching.
 
what year sxr 500?

the 2000-01 was geared down 1 tooth compared to the 99 and older sleds. i know as i had the same problem with the one i had. changeing the gear brought the fuel milage up from 8mpg to 10mpg and brought up the topend to boot. the clutching did not seem to matter in my case as it was just as bad when it was new as clutched.
 
Both of mine are '01's. I am thinking about going down one tooth on the top gear to see if it helps mileage by making the sled work less to accelerate. I don't care about top speed, I rarely go above 70 as it is. I'm surprised you geared up on your 500 Maim.
 
My 600 twin 97 venture with smart carbs can only do like 10 mpg, maybe 11 mpg on a good day.

These particular motors were just thirsty, and you can't do much about it. 600 twins of other brands are much better on gas and not only the e tecs and SDI doos. I heard it on the 4 stroke side, but those doo 800r's are very good on gas for being carbed. I have heard very high teens for those, one guy 19 mpg is his average.
Now if they could only get those doo 800's to stay together....
 
must be the air up there,lol I have a 98 600 vmax and a 95 500 vmax I weigh 350lbs the wife weighs 120lbs and I honestly only use like $2.00 more fuel then her 500 and it has a brand new motor, we can ride all day, hard 100 to 120 miles,on the throttle doing avg 40-70mph and only burn up 8-9 gallons of fuel, that works out to.... If my math is correct between 13 and 15 mpg.
 
Zaj 243 said:
Both of mine are '01's. I am thinking about going down one tooth on the top gear to see if it helps mileage by making the sled work less to accelerate. I don't care about top speed, I rarely go above 70 as it is. I'm surprised you geared up on your 500 Maim.


well i had the sled from new in 04 and after breakin we gps'd the sled. it gps at 80.13mph. i then put a ripsaw and clutched the sled with vmaxjhons set-up from the tec pages. it then gps'd at 80.83 mph indicating it needed more gear as lots of people on here told me that that sled should get over 90mph. added 1 tooth as per 99sx spec and the sled then gps'd at 95mph. with the taller gears cruising rpms dropped to improve fuel economy. sled has no problem pulling that gearing 121" 1.25 track.
 


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