Diminished Fuel Mileage

Warren & Anne

Joined
Apr 10, 2010
Messages
14
Location
Edmonton, Alberta, Canada
Bike
Honda ST1300
Not sure where this could have been placed. I have a 2004 ST1300 with 100K on it (exactly 100k!).

I recently had it serviced in Spring (Ok, not so recent) and the gas mileage was seriously diminished. Normally, I can go about 550 to 580 kilometres to a tank. But now, I am lucky to get 400 to 420!

At first, I thought it was a bad batch of gasoline, but the third tank through proved it to be consistent.

The performance has not changed, leaving me to believe there is nothing wrong mechanically.

But I do think it might be the air filter or valve adjustment.

What do you guys think?
 
I had the same issue with my 06 now with 85K on the clock. I replaced the T-stat and ran a can of sea foam through the engine. Mileage is back up to 43mpg on the hiway.

I'm installing the Audio Vox cruise this winter and doing a throttle body sync so I'll see if the mileage changes after all thats complete.

By the way I thought my mileage decrease could have also been caused by a few valves close to the limit. Did my valve check last week and at 85K i've got six that are right on the limit either loose or tight. I've elected to not adjust them until I do my next check at 100K.

If your bike is like mine its probably not the valves.
 
It's strange to me because the bike was serviced, but immediately the mileage was off.

Ok, so about the air filter, I can only assume the air filter was good as I had a premium service done in the spring. Though, I may change it next service interval and see.

Gas has no ethanol in it.

Temperature gauge is good. Consistently 3 bars.

I thought about the brake dragging too. But the wheels seem to turn without an issue, they spin fairly easy without resistance.
 
Can you tell us in depth what you had serviced in the spring.
Then we can help you isolate each item that they touched.
ie: bad or loose spark plug, high tension leads not seated on the spark plug etc.
 
Ok, pretty much most of the work order is Greek to me.

Double-H Sintered ST. (?)
Replaced oil filter with K&N and oil change
along with the service done (doesn't go into much detail, actually, no detail)
 
Warren & Anne said:
Ok, pretty much most of the work order is Greek to me.
Double-H Sintered ST. (?)
along with the service done (doesn't go into much detail, actually, no detail)
Click to expand...
Not much detail for us to go on also.
Did Honda complete the service?
Are the HH sintered brake pads Honda pads or a different brand.
Where they all replaced?
Did they bleed the brakes?
 
Well, to answer your question Al, I cannot give you a confirmation on anything that you have asked, yes, for the brake pad replacement, but not sure about the bleeding, I wasn't right there when they did it, but the brakes seem to react appropriately, not spongy or anything.
 
Diminshed fuel mileage

Hello,

Ok, I have looked all over the internet (including forums), talked to many shops, still can't seem to find the answer, I have a 2004 Honda ST1300, it's mileage was great until last year when I had it in for service at Triple M ( I realize now what a mistake that was). Anyhow, the mileage has gone down considerably, normally I got close to 600 km per tank, now I get 400. Any clues?

Air filter was in.

Oil is pretty crystal clear.

No brakes dragging.

Temperature reads perfectly normal (3 bars)

Performance seems to be unchanged.

Valves are perfectly normal.

Compression test was done and passed perfectly fine.

Quite the mystery!

Any clues?
 
Most people get mid 40's /mpg so about 270 miles per tank with a 6 gallon fill up .
That equates to 435 km's which is what you are getting..

Are you sure your old figures are correct ?

How much fuel do you generally put in for a fill-up ?

You may want to pull the spark plugs and look to see if you are getting a clean burn which will be evidenced by a light brown/tannish color on the tips of the plugs.
 
Last edited:
For reference as a comparative if it is of any assistance to you I have tracked every tank of fuel since I purchased my ST1300 and I average- in your measure of preference;
56.2 miles per imperial gallon
46.8 miles per U.S. gallon
19.9 Km per litre
5.0 litres per 100 KM.
 
I don't know if this will help, but are you riding the same? I find riding around town I only get about 34mpg but on the interstate, I can cruise at 80MPH all day getting 44mpg. I might be paying a MPG or 2 for the top box and oversize screen.
 
Re: Diminshed fuel mileage

Wow. That's from the mileage stratosphere to subpar. Oil-soaked air filter element? Shop rag left in the airbox? 50 weight oil?
 
I wonder if the K&N filter was over oiled although I would expect that to only have temporary effects once the oil drained away from the filter...
 
Does the K&N filter have a foam sleeve over it? Not sure about the ST1300 K&N, but the one for the 1100 has a foam sleeve that needs to be pitched because it restricts the air intake. If nothing else, buy a new stock air filter from Honda and see if it helps. A can of sea foam won't hurt.
 
Scooter said:
I wonder if the K&N filter was over oiled although I would expect that to only have temporary effects once the oil drained away from the filter...
Click to expand...

vinny said:
Does the K&N filter have a foam sleeve over it? Not sure about the ST1300 K&N, but the one for the 1100 has a foam sleeve that needs to be pitched because it restricts the air intake. If nothing else, buy a new stock air filter from Honda and see if it helps. A can of sea foam won't hurt.
Click to expand...
I read the post where he stated that the oil filter was K&N, but I missed whether the air filter was. Do they make oil filters? Even so, that shouldn't effect fuel economy...

It seems like you are barking up the right tree though with the air filter. I'm curious what they put in (or as you suggested, what they left in). I know a K&N is about 3x as expensive as an oem AF.
 
You must log in or register to reply here.
Back
Top Bottom