Author Topic: Excessive Fuel Consumption, Any ideas?  (Read 9967 times)

Offline zevk

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Excessive Fuel Consumption, Any ideas?
« on: December 21, 2012, 09:21:26 PM »
Hi guys,

My fuel consumption is pathetic, 13 km p/litre!
I've had the 2006 ST1300, for the past 2 months.
It has 49k on the clock and had a major service at 42k. It is in magnificent condition, as new.
The bike is smooth and the plugs are fresh, dry and not fouled with rich appearance.
The bike has stock mufflers, intact and no engine, power-commander mods.
The air filter was replaced (Honda OEM) at 34k (8k ago) and appears to be pretty clean.
Regardless I will order a new air filter (hi-Flow from ebay ok? don't like reusable K+N much and dealer wants $90 for oem)

I wonder if I may have a "pair" or other vaccum leak? Problem is the screws that attach the airbox to the throttle bodies are seized, despite my purchase of a JIS impact driver.... my next otion is to drill grabbit extractors and hope I can remove those soft screws... ughh not looking foward to that job...

any further ideas would be appreciated.

thanks

Zev
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Zev
 
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Offline Breharna

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #1 on: December 22, 2012, 08:05:22 PM »
Zev, not an easy question to answer as there are so many factors to think about when measuring fuel consumption, traffic conditions and riding styles (hard/easy) really weigh into the equation.

So ignoring all that, the dealer would have or should also negate vacuum leaks when they did the major service at 42K's.  It would be obvious if they put vacuum gauges on your throttle bodies to check or synch them at that service.  Also a vacuum leak is USUALLY pretty obvious as it tends to give an irratic/varying idle.

Again if the dealer did the service correctly and its had this consumption issue since you had it, you may have to live with it, especially with the condition you detail about the bike and more importantly the condition of your plugs.  If the colour is good on them and they are the correct plugs, then there is  NO issues with mixtures or ECU issues.

However, there are a couple of little things to consider.  Fuel computers on bikes and cars are fairly optimistic.  There is usually a built in tolerance of up to 10%   The other main thing I would check is your speedo accuracy with a Sat Nav.  Just as a guide, I have seen bike speedo out up to 20% on some of my customers bikes.  This would only give a poor fuel consumption figure if your speedo was reading slower than the Sat Nav.  Your odometer reading is calculated along with fuel used/measured by your ECU (Fuelside) to give you the avereage fuel consumption.

If your speedo reading is okay, then the only thing I would do in the meantime is, fill your tank, reset your trip odometer and when you get low on fuel refuel it and check how many kms you did for the fuel used, just to see if the bike computer is giving shit/incorrect readings read outs.

If your actual fuel usage is OK with KMs travelled and its a wrong reading, just switch off that side of the display, same way you can change the readings from l/100kms and kms/l

I just read this over, and if I go on any more I'll confuse even me.

If your not happy with the consumption after all that, give me a call after New Year and I can have a look at it for you.
Stewie Mac

SKM Motorsport
 

Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #2 on: December 22, 2012, 08:19:02 PM »
Stewie thanks for the info and reply.... I used to be a Honda m/c mechanic many moons ago and agree completly with your analysis.

I calculated the actual kms per usage / litre (not based on the bike computor) and came up with simmiar high fuel consumption avrg 13 kms p/litre using 95 and 98 octane caltex fuel.

I may have to drill and e-z-out / grabbit the siezed screws that secure the air box housing to throttle body and hunt for air leaks, but I would be surprised, as the engine starts/idles/revs smoothly through the powerband at all temps and conditions.

will try replacing the air filter as a start as not looking foward to removing siezed screws, I HATE broken studs with a passion...

thanks again

Zev
   
Zev
 

Offline Brock

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #3 on: December 22, 2012, 08:54:38 PM »
Before any drilling takes place, or any alterations are done, Go for a ride out of town to some place you can ride at a constant 110 Ks per Hour. Top up the tank, and go for a long ride out for 200 or so Ks, tun around and go back and fill up again. this will give you a good base line fuel consumption.

Just to give you an example, my worst consumption is 14.5 Ks per L to and from work, with a bit of wrist twisting. Its a mix of country and town riding. Best consumption this year is 19.0 Ks per l on a 322K ride om majorish roads at around 110Ks.

What conditions are the major use of your bike used in, city stop start or open road. What fuel are you using??
Brock
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Offline saaz

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #4 on: December 22, 2012, 09:38:39 PM »
ST13 does not have any pair system.  Are any codes being thrown on the dash?  If it was a car I would suspect something to do with the oxygen sensors, or a connection to them. Has the bike always had this problem since you bought it?  If you are only getting 13 km/lt usually you would be in jail by now as it would take a really heavy throttle hand to get that.  I might also suspect that the idle circuit is staying on, causing rich running.  A malfunctioning temperature sensor might also cause it to run rich all the time.

As the ST13 is an EFI engine, the basics of oxygen sensor/engine temperature sensor/air sensor (MAP/MAF) are the main items to look for.   Blocked exhausts/cat converters would be a rare thing.
John
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Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #5 on: December 23, 2012, 06:47:23 AM »
Thanks Brock And Saaz for your advice.

Brock, I guess its reassuring somewhat, that your personal worst is closer to my average...

I have been using Caltex 98 octane, for the last 2 months and recently tried Caltex 95 to compare.

My temp is at 3 bars after warm-up and stays at 3 bars.

The fast wax idle works correctly when cold, the bike idles, accelarates and revs smoothly thru all rpms...

I need to trial a long steady ride one day, as Brock mentioned, at a stable 100 kmh and then top up, and calculate consumption.

Most of my riding has been country roads, and some twistys, not much highway riding at all.

Anyone try the "HiFlow" air filter from Ebay $45? Honda dealer wants $90aud for OEM.

Also, I will need rear brake pads soonish, anyone try Ferrodo HH sintered ($50 per pr)

thanks again

 :13Candy 
Zev
 

Offline Brock

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #6 on: December 23, 2012, 10:35:27 AM »
Metal gear do reasonable brakes, cos me about $60 for a full set
Brock
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Offline Poppy Dave

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #7 on: December 23, 2012, 11:23:06 AM »
Also, I will need rear brake pads soonish, anyone try Ferrodo HH sintered ($50 per pr)

thanks again

 :13Candy

Try this guy. He's in the UK, dave@davewilkinsmotorcycles.co.uk - 3 sets of EBC HH pads ( the rear ones being thicker ) for $144.01 AUD = £89.00 GBP ( October price anyway). Dave's a member of the Honda PanEuropean Owners Club.

Dave's a really nice bloke and an ST guru. Drop him an e-mail and he'll fill you in on the thicker, rear pads.
I use them ( now on 2nd set ) and they're just what the doctor ordered.

Take care and all the best for Christmas,

Dave
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Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #8 on: December 23, 2012, 06:42:42 PM »
Brock and Dave, thanks very much for the info re the brakes!

Happy and Healthy new to one and all!
Zev
 

Offline Diesel

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #9 on: December 23, 2012, 11:55:57 PM »
Just putting this out there Zev.....


Both wheels spin freely when on the centre stand don't they...


I was wondering if your brakes were pinching the discs and "always on".


This would seem evident - and sorry if too obvious - but an easy one to eliminate as a cause too.


Cheers, Diesel
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Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #10 on: December 24, 2012, 06:41:27 AM »
hi diesel, thanks for that
no brake drag at all...
Zev
 

Offline Diesel

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #11 on: December 24, 2012, 08:15:43 AM »
Hi Zev - take a look at what YoungOne (Tony) found in his airbox after complaining of rough running...

Linky


Cheers, Diesel
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Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #12 on: December 25, 2012, 05:15:36 PM »
While i'm waiting for the air filter to arrive, in further attempt to troubleshoot the fuel consumption, I just cleaned out the "pair" (pulse secondary air system) reed valves located on the valve covers...

They were cruddy and filthy. its an easy job to do!

Remove the access panel on R + L sides

Remove 2, 8mm bolts that hold the pair housing and remove the air hose clamp and hose.

Pull the reed valves out of the valve cover carefully. Note the position of the base plate (silver with holes, tab goes upwards)

5 minutes of soaking the reeds, base plates and housing cover in brake cleaner, WD40, then a light hand and a brass wire brush, a stiff nylon brush (tooth brush or nail brush) and dry off the reed valves carefully.

Don't attempt to remove the single small philips head screw securing the reed to the housing completly, as it is tapered / mushroomed so as not to fall out. It will sheer off as you attempt to remove it, resulting in choice words  :cuss, centre punch, drill, thread retapping and 30 minutes wasted.

you can loosen the small screw a few turns with plenty of penetrating oil to allow a larger gap for cleaning, just dont remove it completly as it will snap off.  Dont ask how I know all this info....  :fp

Unfortunatly, due to my dislike of paparazzi interfering during my work, no pix supplied...  :13Candy

As my air box screws are siezed, I could not test the reed valves but at least they have been cleaned.

Zev
 

Offline Aj1300

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #13 on: December 25, 2012, 06:34:57 PM »
Zevk, carbie removes that grime better than brake cleaner. Have you tried to bang the air box screws with a Phillips head screwdriver and a hammer?  :blk13
Adam aj1300/ KTM
 

Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #14 on: December 25, 2012, 07:29:02 PM »
Yep tried that trick, even with a JIS impact driver....
Zev
 

Offline Aj1300

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #15 on: December 25, 2012, 08:55:11 PM »
You might have to try and use the easy out way. Maybe try a heat gun on the screws. They might have lock tight on them and a bit of heat, but not too much or you will melt the cover. Good luck :blk13
Adam aj1300/ KTM
 

Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #16 on: December 25, 2012, 09:06:47 PM »
Thanks Adam

Have tried the heat gun, penetrating oil, impact JIS driver, soldering iron, all to no avail....those damn airbox screws are made from butter and stuck like concrete!

Zev
 

Offline STeveo

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #17 on: December 26, 2012, 07:11:07 AM »
Go to a place that sells engineering supplies and get a left hand drill of the size needed and use a battery drill in reverse on your screw heads. The left hand drill will 'bite' into the phillips head and either wind the screw out or drill it out, either way it's out.
(And NO, I'm not taking the piss, I have a complete set of left hand drills for doing just these type of jobs. Great for broken off studs in castings, as the drill 'bites' the studs often screw out.  :thumb)

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Offline Aj1300

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #18 on: December 26, 2012, 05:32:41 PM »
Zevk, maybe you could try drilling the head off with a bigger drill bit. Remove the cover and try and get vise grips on the remaing screw and try and screw it out.. Cheers Adam  :blk13
Adam aj1300/ KTM
 

Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #19 on: December 26, 2012, 05:52:38 PM »
Hi Stevo + Aj1300, thanks for the advice, in anticipation of what may be a disaster, I puchased a "Grabbit kit" from Bunnings which has left hand drill bit and e-z-out on the oppoosite end, to be used with cordless driver / drill. If it doesnt come out this way, I will burr the heads off and then try to remove with vise grips.. not looking foward, but may have to be done... awaiting new air filter from the UK and then will check fuel consumption.
thanks for the advice.

Zev
 

Offline Brock

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #20 on: December 26, 2012, 06:08:44 PM »
Take a run before you do any changes, to give a standard to measure any improvements against. Its always a good idea to have a start point
Brock
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Offline simo

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #21 on: May 23, 2015, 04:54:21 PM »
Hi Stevo + Aj1300, thanks for the advice, in anticipation of what may be a disaster, I puchased a "Grabbit kit" from Bunnings which has left hand drill bit and e-z-out on the oppoosite end, to be used with cordless driver / drill. If it doesnt come out this way, I will burr the heads off and then try to remove with vise grips.. not looking foward, but may have to be done... awaiting new air filter from the UK and then will check fuel consumption.
thanks for the advice.

Hi Zev,

I know this is an old topic. However, I was curious how you eventually removed the air filter box with the stubborn screws? Also, did you finally figure out what was causing the excessive fuel consumption?

John
 

Offline zevk

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #22 on: May 23, 2015, 09:47:47 PM »
Hi Simo,
re the fuel consumption, I was used to the frugale sipping of a VT750, gsx 750 and realize that the V4 is thirstier...I can still get 480-520 km out of a full tank of 96 octane 

below my thread response to stuck air box screws:


stuck air box screws extracted to free up idle speed screw
« on: February 04, 2013, 07:43:15 AM »
QuoteModifyRemove

I got round to removing the seized screws that hold the air box to the throttle bodies.
I removed the tank pivot bolt, seat adjuster and tank safety cable and very gently and carefully secured the tank almost vertically, removed the air filter cover, filter and snorkels.
(good idea to mark them in cylinder order, with a "white out" pen, as well as alignment dots on the air box itself)
 
The 8 (JIS head, 5mm) bolts that hold the air box to the throttle body, were seized, but I removed 4 of them, with VERSA, JIS impact screwdriver.
The other 4 bolts that were not budging, I used a very clever extractor called "grabbit"

http://prograbit.com/Pages/grabitPro.php

it looks like a cordless drill bit. It has a LEFT hand drill bit with shelf stop on one side, then flip the bit over, it has the correct size screw extractor bit the other side.
into a cordless drill, Left - couterclockwise, slow drilling and within 10 seconds, it grabs the stubborn bolt out!
 
Dont forget to block the throttle bores gently with clean rags, to protect metalic shards and mishaps...

I replaced all 8 bolts with Alan, 5mm x 20mm, added flat washers, lock washers and anti-seize paste on the threads.

A three second spray of WD40 onto the idle speed assembly left side of throttle bodies, (just follow the adjuster cable to the pivot assembly, near piston #1) and what has been a very stuck, immobile idle screw, now moves freely and can be easily adjusted.
 
2 hours work all up. Just need to remember to rotate the idle screw a bit every month or so, to prevent it from getting stuck again!

hope this is usefull for anyone with same issue.

good luck
Zev
 

Offline simo

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Re: Excessive Fuel Consumption, Any ideas?
« Reply #23 on: May 24, 2015, 09:26:21 AM »
Thanks Zev - very interesting.

John