Snowmobile World banner

Is It Really This Bad On Gas

3K views 14 replies 8 participants last post by  islandlake 
#1 ·
Hey guys 94 formula Z 583. Loves the gas. Everyone I ride with I destroy at the pumps. Carbs are cleaned and adjusted correct. 1998 670 held 18 bucks, 2004 rev held 22, 97 formula 500 held 19, and my tanker held 38. What the hell is that. Every machine was topped at the beginning and ran equal distance.
 
#2 ·
Wow that is extreme.Make sure the carbs are set up to the proper specs and someone hasn't been playing with jetting etc.How do your spark plugs look?If everything looks ok with the carbs then perhaps the clutches are not shifting out properly.Is the belt in good shape? Also check track alignment and tension.Are all of your idler wheel bearings in good shape?How about ski alignment.Basically anything that might cause rolling resistance.Does the sled seem to coast along ok when you let off the gas or does it feel like its dragging? :crazy:
 
#4 ·
Carbs are jetted 360 a side. I put all new bearings in the suspension this year. Airbox is empty less a sponge. Ski alignment was done when I broke a trailing arm last year. Did the alignment this year. Sled leaves a little late around 4500 rpm stock is 3900 I think. Revs around 8100rpm when to the pin. Off the throttle when rolling it seems normal.
 
#5 ·
Get the specs on the '95 FZ. The carb calibration was changed in '95 to improve mileage. But if the airbox has been gutted, you're kind of on your own for jetting.
 
#6 ·
7800rpm max

340s is the correct jetting for the 95 FZ 583 :)
 
#7 ·
Does the machine start hard, like it is always flooded? You may want to take apart and clean, or rebuild your fuel pump. I had a 580 that would start like a bear and then use way too much gas. There is a tiny vent in the top of the fuel pump that would get plugged and it would just pump way too much fuel. After finding that one year, from that point on, each year when I cleaned the carbs, I would take the pump apart and clean everything real good.
 
#8 ·
Originally posted by FreezerBurnt@Jan 12 2005, 03:01 AM
7800rpm max

340s is the correct jetting for the 95 FZ 583 :)
[snapback]387838[/snapback]​
I think there is more than a main jet change to the '95 update.
 
#9 ·
OKAY I will try the fuel pump thing. My airbox looks good revrnd. Nothing out of the oridnary that I can see. The sled used to be a grass drag machine. Well okay it was a grass drag machine all it's life up until last winter when I bought it. He told me everything was put back to original. So when I did the carbs this year I checked everything. I also pulled the secondary apart just to be sure. I will try the fuel pump thing if that doesn't work. The hell with it.
 
#10 ·
Originally posted by revrnd@Jan 12 2005, 08:21 PM
I think there is more than a main jet change to the '95 update.
[snapback]388188[/snapback]​
I posted all the 95 FZ specs(jetting/needle,screw setting etc) for him revrnd 2-3 times already since November

yet he don't want to listen :bash:

he just wants to run everything to 94 specs :slick:

yet crys about MPG

BTW the fuel pump is NOT rebuidable

Guy asks for help yet does not want it

SO IMO don't bother complaining about a poor MPG :!:
 
#11 ·
Some fuel pumps are rebuildable, some are not. The one on the 580 that I had was.

Here is a link that show rebuild kits for some common pumps:
http://www.mikuni.com/c-fuel_pumps.html

If your pump is not rebuildable, it is no big deal, just take everything apart carefully, clean it good, wipe the diaphragms off with something like a paper towel (something that will not leave anything, such as lint on the surfaces), and put it back together the way it came apart.
 
#12 ·
Freezer. Relax man. You have never sent me over jet sizes and I have not asked for your help specifically once. If you are even referring to me. Repeat the posts where you told me since november the 3 times about the jet sizes. If you did I apologize, otherwise don't reply to anything I post. I am not intrested in your comments. A simple if you change the carbs to 95 specs it will be better or try this would of been fine. I am not changing to 95 specs. It will be hard for me to hold back the tears but I will do my best.
 
#13 ·
no ones ever needs to ask for my help :)

I just give help whenever I can SWRules

Here you go :)

Here is one time I tried to help


the reason the 95s have diferent specs was to improve performance and MPG
 
#14 ·
Grass drag sled....hmmm.....are you sure that that engine is stock? I think you might have some tuning ahead of you...the 95 carb specs might not be enough...
 
#15 ·
Never buy a grass drag sled that was used just to grass drag. These sleds have to be jetted for the warmer temperatures and a lot of times these guys will port and install high compression heads which causes poor fuel economy. Grass drag racers don't care about fuel economy. Personally I would take the advice given and change to the 95 specs and see what happens, it won't cost much to do this. Just make sure to keep an eye on the spark plugs to make sure you see that cocoa brown color that represents a good fuel air mixture. Fuel pumps wont give you too much fuel.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top