ST1100 Gas Mileage Decreasing

no-troll-feeding.jpg
Troll
Internet
In Internet slang, a troll is a person who sows discord on the Internet by starting arguments or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community, ... Wikipedia
Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial. Like any pejorative term, it can be used as an ad hominem attack, suggesting a negative motivation.

The advice to ignore rather than engage with a troll is sometimes phrased as "Please do not feed the trolls."
 
Last edited:
no-troll-feeding.jpg
Troll
Internet
In Internet slang, a troll is a person who sows discord on the Internet by starting arguments or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community, ... Wikipedia
Application of the term troll is subjective. Some readers may characterize a post as trolling, while others may regard the same post as a legitimate contribution to the discussion, even if controversial. Like any pejorative term, it can be used as an ad hominem attack, suggesting a negative motivation.

The advice to ignore rather than engage with a troll is sometimes phrased as "Please do not feed the trolls."
Thanks! :)
 
Thought I'd update this thread with my recent mileage. Running 1-1/2 tanks of seafoam through it seems to have helped. I'll try to update this every few months for anyone that interested. Thanks for the tips.
I'd still like to sync my carbs but haven't gotten around to it yet... need to buy or make a tool for it.

MPG2.JPG
 
need to buy or make a tool for it.

or borrow; invite people over for a tech day!
:)

An air flow meter would be enough for you to do the job...
I have one that I'll loan you if you pay shipping both ways; but, at that point you need to look at buying vs. borrowing.
I saw them on ebay for 38 plus shipping...

Please remember you're syncing to the back left as you sit on the bike...
 
Paul,
Will you use an air flow meter or measure & compare vacuum with carb sticks?
Tim

Thought I'd update this thread with my recent mileage. Running 1-1/2 tanks of seafoam through it seems to have helped. I'll try to update this every few months for anyone that interested. Thanks for the tips.
I'd still like to sync my carbs but haven't gotten around to it yet... need to buy or make a tool for it.

MPG2.JPG
 
Paul,
Will you use an air flow meter or measure & compare vacuum with carb sticks?
Tim

compare vacuum with all components in place, i.e. air filter, air filter housing, etc.
 
Yes, I saw that 'debate'. I think the vacuum method is better but if someone wants to use airflow, no skin off my back. No bike is setup perfect anyway.
 
Thought I'd update this thread with my recent mileage. Running 1-1/2 tanks of seafoam through it seems to have helped. I'll try to update this every few months for anyone that interested. Thanks for the tips.
I'd still like to sync my carbs but haven't gotten around to it yet... need to buy or make a tool for it.

MPG2.JPG

Yes, Please keep us updated.
 
FWIW, another MPG update for my 2001 ST1100. I'm guessing that my MPG decrease from Sep13-Jan14 (what started this thread) was somewhat due to winter blend fuel.

In any case, I'm back to 45-50 MPG.

mpg2.JPG

Note: The two low points in Apr14 (40MPG) were 300 mile slab trips against a VERY strong headwind. The return trips (same day, same wind) were 49MPG with a good tailwind.

Note 2: the only thing I've done since I started this thread (other than oil change, fork rebuild & brakes) was a few tanks of Seafoam. I've not synced the carbs.
 
Last edited:
I noticed my mileage was decreasing on my ST1300. I installed NGK idridium spark plugs and now it is back where it used to be.

Sent from my SM-N900V using Tapatalk
 
With the age of the bike, I would suspect the carb boots on head side are pulling a wee bit of vacuum by. Replacing them with new when I did the coolant elbows/O-rings brought my bike mileage on the slab @80mph from its gradual loss of mileage down to 44mpg back up to its normal 50-52mpg at same continued speeds, with doing absolutely nothing else.

Those carb boot clamps have bottom stops, so as not to overtighten. Having said that, they are, by design to go on new carb boot installation, not re-use of originals;).
 
For anyone that's interested, another MPG update from my ST1100. Overall, I've average 46.4 MPG since Aug2013... the vast majority during daily commuting to/from work, 55 miles round trip.

The lower numbers were generally trips at higher speed, i.e. 70-80mph, unless it was a return from an RTE, which was usually a little faster! :dr11:

gas mileage.JPG
 
Last edited:
Might as well throw in my 2 cents worth. Picked up my 01 with 23,000 miles on it and now have just over 110,000. I track mileage for every tank of gas. Most of my riding is also commuting to and from work, 55 miles round trip, 35-65 mph. From the time I bought the bike to now, I average 42-44 mpg, unless 2-up w/gear and riding fast (within the posted speed limits, of course). I have never seen anything close to 50 mpg!
Ride Safe
 
IMO, location can ALSO affect mileage. A noticable drop in mileage in cage when east of K.C. Kansas/Missouri AND on the STeed west of L.V.,Nevada. The 'up to 10%' alcohol content in fuel may play a part in this.
Also, ANY fluxuation of idle at operating temp. indicates a need for a re-sync, which needs to be combined first with an idle mixture check and re-set THEN sync.
Moist dusting around carb boot bases indicate a slight vacuum leak. That was the case with mine, and as I previously stated, the mileage jumped back up substantually with new carb boots being the only change when I replaced the coolant elbows/o-rings;).
 
A resync is something I have not tried (bike runs good) although I have contemplated it. However, I also replaced the carb boots and a pinched/nicked vacuum line when I did the coolant lines/elbows - all without any noticable change in mileage. Maybe my bike is just happy at 42-45 mpg!
Ride safe.
 
Back
Top Bottom