Gas mileage

[Ron Vroom]

Any ideas from anyone about why I am getting poor gas mileage (like around 5mpg)? I've got a 1996 Yamaha VMAX 600 XT with 3400 miles on it. Yesterday I ran 26 miles at no more than 30mph which kept the tach at 5,500 rpm, on a groomed railroad trail, straight and level and used 5 gallons of gas. The day before I ran this same trail segment, plus a run across a lake, and a curvy, up and down loop for a total of 42 miles which took 7.4 gallons of gas giving me 5.6mpg, but my speeds were much higher with short bursts up to 65mph in spots. The drive belt appears to be within the wear limits, and the engine sounds fine. I'm thinking it must be a carb or clutch issue or maybe a combination. A range of 50 miles on my 10 gallon tank severely limits any long distance trail riding.

[fatcat45]

sounds like my tundra...

[icerube]

Check the fuel pump, might be a torn diaphram. Good luck.

[Macgyver55]

It sounds like maybe one or both of your clutches is not operating correctly, or you have some drag caused by worn components or sticking brake.

If it were dumping too much fuel it would surely be running poorly and fouling plugs. Does it idle and rev normally?

Does the track rotate freely? When you let off the throttle does it slow down quickly?

Try suspending the rear of the sled SECURELY from a rafter or sturdy tree branch. (Keep clear of moving parts) Run it up a bit with the hood open to watch the clutches and see if they go through the full motion smoothly. The drive clutch should pull together all the way until the belt is up near the top. The driven clutch should spread until the belt is nearly at the bottom. Dont go wild and do it too long but you will see quickly if they are working or not.

[slurpie]

I would agree that its not in the carbs the sled would run bad or have fuel all over. Also check the track tightness.

[BoxMN]

Not to hijack, but on similar type question, is about 12-13 mpg about what I should expect for '02 xc500 and '02 yammie Venture 2-up with 600 engine? I think that is about what I am getting, considering trail riding and plenty of smile-inducing "go-fast" moments

With your yammie 600 I would think you should be about the same as me if all is well. I did just put on new slides and checked chain tension, track tension, etc.

[Shack]

Box, I would say that is about the norm for the two-stroke 500 & 600.

As far as the V-Max mid-90's 600, this was a fuel hog. All you can do easily is check for belt wear or grease/groves on the primary or secondary. Second would be to re-jet with out going too lean as to melt down the engine. Third would be to maybe change gears in the chain case. From the buddies I knew who had them, you are only going to gain a mile or two per gallon at best. 5-8 mpg was about the norm for the Vmax 600.

[Loose]

Ridin ditches my 2000 xc 600 got about 8 mpg the wifes 03 Yamaha 600 triple gets about 6 or 7 in the same conditions.

[BoxMN]

Thanks guys, I know my wife is slow driver, and I am usually pretty relaxed "old man driver" with a few speed spurts, but I guess not as throttle happy as many, hehe.

[dan z]

well for starter its snowmoblie they dont get good mpg. i have a 2003 xc 600 i get about 8 to 10 in the ditch and groomed trails up to 13.

[buckx37x]

just to throw this out my 01 mxz700 gets 10mpg,little worse pounding it ,little better trail riding.

[Ron Vroom]

Thanks everyone for your imput and the thoughtful responses. I also checked with my local service center and your suggestions were right in line with what they said. So here is what I have done. I did put a new belt on after finding my old belt was a bit narrower then what I thought. I siliconed the clutches. I put in new iridium plugs, sprayed some carb cleaner thru the carbs. Checked the track tension which appeared to be correct. Will give it a run tomorrow to see if there is any improvement. If not, will then tackle the carb and jet settings. Beyond that, I suppose it means a session at the service center. If I could achieve 8 mpg, I can live with that, which would give me an 80 mile range. Maybe I am just spoiled by my '86 Exciter which gets me further down the trail. I suppose the only real solution is to get a 4 cycle sled which I can't afford.

[Esox_Magnum]

My 95 Polaris triple gets at best 100-120 a tank IF I stay off the throttle, but thats no fun so normaly if I get 80-100 a tank I'm happy.

[slurpie]

2002 mxzx 700 144 2" 11mpg riding ditch driving hard. And four other ski-doos get real close to the same.