Poor fuel milage

[fastsled]

Thanks guys changed a few of the suggestions in clutching and jetting its a whole lot better now .
Thanks very much

[mark the shark]

Hi Dan, and welcome to the site! :schild27: :schild27: Vmax-4's aren't known for their stellar gas mileage, but it sounds like your's is below the norm. There are a lot of things that can cause this. Start with the obvious - are the suspension idler wheels turning free? Is the track alignment and tension adjustment in spec? Ski toe in/toe out adjusted correctly? Is the brake adjustment too tight? Drive belt width should be 1.36" with a new one, the wear limit is 1.3". Since the sled has a comet clutch instead of the stock clutch, some of the factory specs may not apply. I don't know much about that, but some of the guys here will. Check the clutch alignment, too. If the clutch has been changed, it's possible that somebody changed the chaincase gears and set it up for drag racing, which would alter your gas mileage. You would have to remove the chaincase cover and count the teeth on the gears, and the links in the chain to determine if it's stock or not. You can download a service manual for your sled here: http://www.vmax4.com/vbulletin/showthread.php?t=4779

Shark

[opsled]

A 102 is a small diameter clutch and won't allow the secondary to fully shift as it's not an overdrive clutch like the OEM Yamaha. A 108 is the same diameter as OEM and would be better but I would get the right Yamaha clutch on that thing with yammiegods setup and you will have a whole different animal. Vmax4's arn't known for being fuel mizers so don't expect to pass a lot of gas stations even after you get it right.

opsled

[Ken]

The stock updated jetting for the 92 is 135 mains and 47.5 pilots. I would also check the carb sync, float height, and needle settings.

Have a look at the secondary clutch, does the helix appear to be nickle plated? Can you post some pics of your secondary clutch, ramp shoes, helix and bushings? Yamaha did a bunch of updates to the clutching on the 92.

Ken

[Ken]

Dan,

They've never ran a 150 main in a Vmax-4 that I am aware of. Unless they ran special jetting in Regina, you're dealer gave you the wrong specs. Have a look at the attached document.

Do you know what your current shift rpm is?

Ken

[Ken]

Unless they ran special jetting in Regina

That wasn't meant to be sarcastic, if I'm not mistaken it gets really cold in Regina.

Ken

[BTC]

Hey Dan,
I would start with the cllutch as noted above.

I am from Regina also, I have a 93. I definitly get more than 60Km per tank. Hope you get it fixed up. Maybe will see you out on the trail sometime.

[dealermotorcycles]

I`m in Winnipeg Manitoba and only get 63 miles or 100km to a tank on the `93.The `96 I did pull 73 miles out of it once looking for gas,but that was being very eazy on the gas.

[Ken]

I`m in Winnipeg Manitoba and only get 63 miles or 100km to a tank on the `93.The `96 I did pull 73 miles out of it once looking for gas,but that was being very eazy on the gas.

That's about average from what I've seen, 6-8 mpg. Fastsled is only getting 3.6 mpg........ouch!

[luckyone]

the slower i drive my 800,35 to 45 mph the worst the mileage(6.80mpg)the faster i drive it55 to 65mph(between 9 and 10mpg)

[WEATHERBY460]

I have found more then once on older sleds.....cracked/cut fuel lines.

It might be from age, or even someone tightning a hose clamp to tight and tearing the hose.

[fastsled]

THANKS ALL. I changed a few things in clutching re jetted it and it seems to be Ok now up around the 60 mark :clap:

have a great day