stanster
New member
Took my "new" 95 Vmax dx 600 to Gaylord this weekend and got 3 MPG running easy with the kids. Motor performed poorly off the line snd didnt really do much on the top end. Pulled the carbs and checked the floats everything looked fine. No leaks, not running out of the carbs no fuel smell. Some smoke when taking off but sled will idle and didn't foul plugs. Used 3 tanks of gas and gallon of oil in 90miles. Compression is equal at 125psi. I did find one problem in that the adjusting eccentric on the one carb is gone so the carbs probably aren't in sync. I wanted to know if that would cause this poor fuel economy. Any ideas on what to look for would be appreciated.
daman
New member
Man you got some serious problems going on,,my '95 gets 10-11 easy
you need to check carb settings(jets) and make sure everything is stock,
maybe jet down some,also check throttle end play then adj.oil pump.
how's clutching, what r's are you seeing at WOT,track overly tight?
Compression i think is down a little should be around 150,94-95's
had a thin HG stock back then,but 125 isn't bad should still run good.
you need to check carb settings(jets) and make sure everything is stock,
maybe jet down some,also check throttle end play then adj.oil pump.
how's clutching, what r's are you seeing at WOT,track overly tight?
Compression i think is down a little should be around 150,94-95's
had a thin HG stock back then,but 125 isn't bad should still run good.
FuzzButt
New member
The only time my any sled of mine got mileage that bad I had fuel pouring out the drain nipple on the float bowls. I could watch the fuel gauge go down from 3/4 a tank to empty in the 12 miles between Kinross and the Soo.
Your issue is doubly bad. You should not be using that much oil. Maybe a quart in 90 miles not a gallon. I bet it runs real bad and smokes like your running a smoke screen in battle. I don't remember what carbs the '95 had on it. But something is way out of whack. Basically if I were you I would take them off the sled and go thru them with a fine tooth comb. Or in your case a small brush and a few cans of carb cleaner. With the mileage your getting something is wrong. I'm leaning towards a passage plugged/screws set wrong or the choke circuit is always on. Trouble is your using 4 times the amount of everything. and if you go by the 3MPG and 1gal of oil that is ~30 to 1 which is a little rich but in line with the 4 times as much as normal for gas and oil.
Carbs out of sync will not cause this but certainly they need to be in correct working order. Replace any broken part and try to get the floats the same height. Without knowing if it is a TM or VM there is no specifics I can add. I would make sure that all fuel and air passages anywhere in the carb are clean and clear. There are a bunch of them so take your time going thru them all. Also while your going thru it you might want to verify the main and pilot jets are the correct ones for 1000 feet/20 degrees. Look at the chart in your owners manual. With your problem I would buy new ones. 30 gallons of gas is much more expensive than 4 jets. Make sure the needles are the correct type and that they are set the same height as recommended. Since you are not the original owner you need to set a baseline and go from there. It is quite possible that multiple things are wrong so if you fine one thing odd fix it and keep looking.
Good news is I doubt it is a motor issue, It is not an electrical issue either. One final thing make sure your fuel and vent lines coming from the carbs are in good condition. There should be no kinks and the vent lines that drop down about a foot should not be near anything that moves or in a place where there is a lot of air movement. A low pressure area in the vicinity of the hose ends will change the pressure in the float bowls. This is why there is a windage plate on the secondary clutch.
Hope that helps. Keep us informed of your progress and take pictures. Pictures help.
Here is a picture of my rack mounted TM38 off of my '97 600 after I cleaned them. http://www.mykeeshond.com/snowmobile/TM-38-on-bench.jpg
Your issue is doubly bad. You should not be using that much oil. Maybe a quart in 90 miles not a gallon. I bet it runs real bad and smokes like your running a smoke screen in battle. I don't remember what carbs the '95 had on it. But something is way out of whack. Basically if I were you I would take them off the sled and go thru them with a fine tooth comb. Or in your case a small brush and a few cans of carb cleaner. With the mileage your getting something is wrong. I'm leaning towards a passage plugged/screws set wrong or the choke circuit is always on. Trouble is your using 4 times the amount of everything. and if you go by the 3MPG and 1gal of oil that is ~30 to 1 which is a little rich but in line with the 4 times as much as normal for gas and oil.
Carbs out of sync will not cause this but certainly they need to be in correct working order. Replace any broken part and try to get the floats the same height. Without knowing if it is a TM or VM there is no specifics I can add. I would make sure that all fuel and air passages anywhere in the carb are clean and clear. There are a bunch of them so take your time going thru them all. Also while your going thru it you might want to verify the main and pilot jets are the correct ones for 1000 feet/20 degrees. Look at the chart in your owners manual. With your problem I would buy new ones. 30 gallons of gas is much more expensive than 4 jets. Make sure the needles are the correct type and that they are set the same height as recommended. Since you are not the original owner you need to set a baseline and go from there. It is quite possible that multiple things are wrong so if you fine one thing odd fix it and keep looking.
Good news is I doubt it is a motor issue, It is not an electrical issue either. One final thing make sure your fuel and vent lines coming from the carbs are in good condition. There should be no kinks and the vent lines that drop down about a foot should not be near anything that moves or in a place where there is a lot of air movement. A low pressure area in the vicinity of the hose ends will change the pressure in the float bowls. This is why there is a windage plate on the secondary clutch.
Hope that helps. Keep us informed of your progress and take pictures. Pictures help.
Here is a picture of my rack mounted TM38 off of my '97 600 after I cleaned them. http://www.mykeeshond.com/snowmobile/TM-38-on-bench.jpg
Reeds, if you haven't inspected them yet. Then go after the rest
cougar1985
New member
not sure if the carbs are the same as i had on my kawasiki intruder but it had the same problem and what it was ,was the jet was plugged with dirt.(both jets)im not sure my vmax would get 3mpg running on 1 cylinder!also as posted earlier check the reeds,as if you got the carbs off your right there anyways.i put a set of carbon-teck reeds on last year and what a diff they made.
check all you r fuel lines and line to the fuel pmp make shure there's no leaks.
stanster
New member
Hey guys a little background- when I got the sled one of the carb slider bolts had fell out and it wasn't working I put the bolt back minus the eccentric for syncing. When I took the carbs off tonight to inspect the reeds(Is there any way to check if they are good) I noticed something on one of the pistons, this is the bank that the slider WAS working on when I received the sled. Just wanted to know if a motor can show good compression and have scored piston or broke ring?? Thats not oil on the piston, its not rough, it almost looks chrome 
Attachments
daman
New member
Whats the ring look like?
yes my buddy had the same problem his pistons where pretty scuffed so was the cylinder the compression test was go but when he did a leak down test it showed up.He fought all winter with it.It was running a couple hundred rpms low.
stanster
New member
Hey Pro did his sled suck gas? Daman from what I could see of rings they seemed a bit more rigid than the other cylinder, like when you moved the crank back and forth(slightly) the rings in the good side had afraction of play and the ones on the attached pictures side seemed stationary.
Attachments
daman
New member
That don't look good,, i think you need to tear her down.
Well he only ran it 1000ft ata time radar running that's all he did with the sled but the pics look just like his.Time for a rebuild.
stanster
New member
Thanks guys, Guess me and the ol' hog are gonna go on a field trip back to the seller 
daman
New member
I would..good luckstanster said:Thanks guys, Guess me and the ol' hog are gonna go on a field trip back to the seller
FuzzButt
New member
Ya time for pistons and rings for sure.
Keep looking around for other oddities there may be more than one thing wrong. One causing another causing another kind of thing.
The reed petals need to look uniform across the petal with no cracks and should be within a thousandth of the seat. If they want to lift up a bit they are tired and a new set is in order.
It is a too much fuel flow issue you can tell by the wash on the piston crown. The area by the exhaust port should not be that shiny. You should really be able to tell with the head off.
My guess is parts will run you between 3 and 4 hundred if you want to do it right and about $250 if you go the aftermarket route. It should be an easy afternoon job as long as the cylinder has no damage. If it is damaged add $200 for repair to the total.
Keep looking around for other oddities there may be more than one thing wrong. One causing another causing another kind of thing.
The reed petals need to look uniform across the petal with no cracks and should be within a thousandth of the seat. If they want to lift up a bit they are tired and a new set is in order.
It is a too much fuel flow issue you can tell by the wash on the piston crown. The area by the exhaust port should not be that shiny. You should really be able to tell with the head off.
My guess is parts will run you between 3 and 4 hundred if you want to do it right and about $250 if you go the aftermarket route. It should be an easy afternoon job as long as the cylinder has no damage. If it is damaged add $200 for repair to the total.
mrfreeze
New member
if i were you i would look into getting your cylinders redone mine was the exact same so i was able to clean the jugs and put in a new piston set and 150 km later there went the jugs and bad you too much wear in the cylinder walls one of the rings are going to turn and realy f$#@ up the jugs just telling my story hope it helps