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Honda ST1300 Section => Honda ST1300 General Questions => Topic started by: Dragonstaff on July 19, 2025, 07:48:48 PM

Title: Fuel Consumption
Post by: Dragonstaff on July 19, 2025, 07:48:48 PM
Over the last few months my fuel consumption has gone from 18-18.5 km/l down to 16-16.5 km/l average. I haven't changed my riding style, or where I ride to allow for it, so I am wondering about a couple of things.
The bike has just ticked over 189500 km, has new Iridium plugs in it and a fresh service but the 70km trip today hasn't made a noticeable difference.
Title: Re: Fuel Consumption
Post by: Williamson on July 19, 2025, 09:18:42 PM
Has the air filter been changed?
Title: Re: Fuel Consumption
Post by: Dragonstaff on July 19, 2025, 11:21:00 PM
Has the air filter been changed?

It has a K&N that was cleaned and re-oiled last service, and had the dead bugs blown out of it this time.
Title: Re: Fuel Consumption
Post by: ruSTynutz on July 19, 2025, 11:40:51 PM
Dodgy thermostat can affect your fuel economy... :/
Title: Re: Fuel Consumption
Post by: Brock on July 19, 2025, 11:49:01 PM
The K&N filter is the cause, It was a well known problem. The outer foam (oiled ) filter causes to much restriction and makes the bike use much more fuel. Go back to the standard filter and all will be good.
Title: Re: Fuel Consumption
Post by: ruSTynutz on July 20, 2025, 01:26:37 AM
The K&N filter for the 1300 doesn't have the outer foam, Brock...  :popcorn

(https://i.ibb.co/VYCpzR1K/K-N.png)
Title: Re: Fuel Consumption
Post by: Dragonstaff on July 20, 2025, 08:01:58 PM
The K&N filter is the cause, It was a well known problem. The outer foam (oiled ) filter causes to much restriction and makes the bike use much more fuel. Go back to the standard filter and all will be good.

The filter was fitted when I got the bike, so I don't think that it is the problem this time. This is a fairly recent change.
Title: Re: Fuel Consumption
Post by: Dragonstaff on July 20, 2025, 08:05:19 PM
Dodgy thermostat can affect your fuel economy... :/

It hasn't changed the way it warms up, or where the temp gauge sits when riding. I would think that if the thermostat was U/S, something would show. When the other bike had its stick open, the temp stayed down on the first bar instead of the third. That was the hint that it was stuck.
Title: Re: Fuel Consumption
Post by: John g on July 24, 2025, 10:37:07 AM
 :bl11.   Is it possible that where you get your fuel has been selling dodgy
             Old fuel which has lost some of its octane ?
Title: Re: Fuel Consumption
Post by: Shiney on July 24, 2025, 06:56:57 PM
Since you just replaced the spark plugs, maybe check that they are sparking properly?
Title: Re: Fuel Consumption
Post by: ruSTynutz on July 24, 2025, 08:04:47 PM
Speaking of spark plugs...Did you buy them from a reputable seller?
There are a lot of fakes out there...  :think1

https://youtu.be/vpH4O14EBxA?si=AumCg0AnDOvdbIUO
Title: Re: Fuel Consumption
Post by: Dragonstaff on July 25, 2025, 08:13:52 PM
:bl11.   Is it possible that where you get your fuel has been selling dodgy
             Old fuel which has lost some of its octane ?

Fuel from various places, John.

Since you just replaced the spark plugs, maybe check that they are sparking properly?


The increased fuel consumption came before the new plugs, and was one of the reasons for changing them.
But checking spark might still be a good idea.

Speaking of spark plugs...Did you buy them from a reputable seller?
There are a lot of fakes out there...  :think1

https://youtu.be/vpH4O14EBxA?si=AumCg0AnDOvdbIUO

I don't know how reputable they are, but I bought NGKs from a bricks-&- mortar source in Sydney, so they should be good.
Place in Castle Hill called the Automotive Superstore.
Title: Re: Fuel Consumption
Post by: Shiney on July 26, 2025, 06:54:21 AM
Also have a look through the discussion in the following link, it may not apply but there are some good ideas you could check.

https://ozstoc.com/index.php?topic=12754.0


Cheers
Shiney