Decline in Gas Milage

[lockwoodjohn]

Hi Everyone,
This has kinda got me stumped, Last riding season I noticed a decline in my gas
mileage . I was getting 45 mpg to 50 mpg. Now I am down to 34mpg to 36 mpg. I haven't changed my riding habits . The bike, 95' Voyager always got good mileage right from when I first got it. 2 years ago. I can take a peace of cardboard the length
of the bike, Lay it on the shop floor. Park the bike on it let it sit there all week and not one drop of coolant, oil, or gas. I have put the bike on the center stand and ran it
looking for any kind of fuel leaks. I found none. I even had it up on the jack, both wheels off the ground, Ran it, Laid next to it with my head and shop lite under it and found nothing . No leaks any where. I can not smell gas anywhere either. A little
history what I did to it. Iridium plugs which have 11, 198 miles on them. The fuel filter was changed with a oem kawasaki fuel filter, It has 6,185 miles on it I just
put a new air filter in it. It has 119 miles on it and clean as a whistle But get this the bike runs great!! Idles smooth, plenty of get up and go, Starts right up in the morning or when cold. The only thing it does once in awhile is at idle, 800 rpm it will all of a sudden rev up to about 1200 rpm. It has done this from when I first got it. I just blip the throttle alittle and it goes right back to 800rpm. It did this even when I was getting 45mpg to 50mpg. So I don't think that is causing the bad gas miliage. The bike has 93,000 miles on it. The only thing I have not changed is the spark plug wires or the plug boots. ANY help or tips or suggestions !!! I'm all ears!!
This really bugs me!! Cause I can not find the cause. Thanks alot, Hope you people
can give my some direction to go in. Thanks again lockwoodjohn, John Kinney o yea, The coolant manifold o rings just replaced at 92,783 miles. Oil pump oil seal replaced also and coolant pump pipes seals also and pump cover o ring to. like
i said before, No visible leaks of any kind anywhere.

[Tonyvdb]

When was the last time you ran some Seafoam in the gas tank?

[lockwoodjohn]

I run seafoam in the gas tank every 3rd tankfull

[Highway Rider]

Just a thought but could the choke be stuck open some. Even though you push the lever all the way back would not hurt to make sure it is working correctly on the carbs.
Have you pulled plugs to see the coloration of them?

[Tim in NC]

If it's not leaking gas, then it's burning gas.
Carbs would have to be set to run richer than last year. Any carb work done last winter? I agree that the plugs will show if the mixture's too rich.

[lockwoodjohn]

no, No carb work was done.

[voyager55]

Check carb sync, drain carb bowls. Something might be plugged or getting plugged

[lockwoodjohn]

Hi everyone,
thanks for the tips. this weekend I will check operation of the choke, Drain float bowls. run somemore seafoam and see what happens. Thankyou all , Again John Kinney

[bikerking.biz]

I've had this problem too. As you, I found no leaks by running the bike, or no gas seen anywhere on the floor, bike, etc. But when I went to change the fuel filter and moved some of the rubber hoses (I think it was the one that connected the fuel tank to the fuel pump, a pin size stream of gas squirted out. There was a small hole in the hose, but not big enough to see gas as I guess it would evaporate when running, and would not leak when sitting still. I replaced that hose, and my gas mileage returned to it's original goodness. Problem solved.

[cushman eagle]

You might also check to see if you still have carb vacuum to the ignitor.If not you would not have proper part load ignition advance,which will have a negative effect on milage.

[lockwoodjohn]

Hi Everyone,
Well this Saturday I drained my float bowels. Also I checked my maint. log and remembered I had taken my choke cable/ lever apart to use my cable oiler on it. I must have adjusted my choke cable a little to tight. Because on full choke it would rev up to about 4500. It never reved that high before. I readjusted my cable. lubed the throttle linkage with dry moly lube. Took Voyager for about a 150 mile ride yesterday. Took bike to work today. Topped off tank. O yea.. I found a gas station in Ithaca that has Ethanol free gas. 91 octane also . figured out mileage got 48.2 mph.
I would like to thank everyone for your tips and advice. Part of my 150 mile ride was on RT 86, Fighting a head and side wind also at 65 mph. And it still got 48 mpg.
Again, THANKS ALOT to everyone that helped me out. Boy I will tell ya, When you work on your own bike and the project goes well. It leaves you with a good feeling!
But some times they can make you feel really foolish. Do you know how many times I looked for fuel or vacume leaks that were not there!!! Thanks Everyone.
John Kinney,lockwoodjohn