What might cause a 10 mpg drop in my fuel mileage

[blaine]

Originally Posted by burkbuilds

After just one 5 oz. treatment of fuel injector cleaner in the tank, I'm back up to 56 mpg, which included about 45 miles around town in traffic before I left, so, I think it was mainly a dirty carb that caused my loss of gas mileage.

I usually put some SeaFoam in my tank about once every month.
:2tup:

[burkbuilds]

My mileage around town this week was right around 58-59 mpg. I went 96 miles on 1.6 Gallons (58.75 mpg). I think everything is now back to normal. Amazing what a little crud in the carb can do to your gas mileage.

[alanmcorcoran]

There seems to be some inherent sensitivity in the GZ carb to both lack of use and (I suspect) crappy gas. I worked in a gas station for a few months back in the seventies and the guys that filled the tanks told me there was all kinds of crap in the tanks (water, rust, dead rats) that, as far as they knew, wasn't coming out until the tanks were replaced - which was not something that was done very often (every 30 years?). (No one ever came to "clean" the tanks.) I worked at a Texaco, but the guys that filled it told me a lot of stations (back then, anyway) all got their gas from the same supplier and the supplier himself had rust and water in HIS tanks, and they had water and rust in the supply truck tanks, etc. I don't think they make the tanks out of steel anymore but I've stopped at some hinky looking joints out in the boonies when I didn't have an option and god knows what extra flavoring I got with my 87 octane.

There are filters at various points in the process, including the vehicles themselves, but I suspect the GZ allows particles through that it maybe shouldn't and once you get one of those lodged in the jet you are screwed.

[Water Warrior 2]

An inline gas line filter is a good idea. It may go a long way to filtering out the extra no cost additives. BB's bike is no longer a GZ but still can be subject to crude and stuff. FI bikes mostly have filters in the tank and are a lot more trouble if they pack up but so far so good with the Vstrom after 50,000+ kms. Top tier fuel suppliers are probably the way to go. Mom an Pop suppliers may not have a decent additive package and less quality control.