[jork]

worst (circuit day) - 1/8 l/km
60000 off my kilometer - 1/14 l/km (reserve is 30 kilometer)

Did some fixing/maintenance last year
steady 140kmh on highway - 1/19,5 l/km
steady 160+kmh on highway - 1/17 l/km

last 1500 kilometers - 1/18 l/km

 

[coz]

There is the 'Yosh Box' besides the TEKA that can alter the factory ECU programming internally as well as a couple aftermarket companies that will reflash your ECU if you send it to them. I'd want to see the maps that will be flashed before sending it out trusting them to do what's best. What's best for me might not be what is best for you.

Injector patterns can't be altered beyond cleaning to make sure they're spraying correctly but you can check the pressure by 'T'ing in a gauge to watch while riding. Mine would drop to 20psi or lower under throttle when the filter was clogging up and the engine still ran surprisingly strong even though it was being strangled. Of course, with a new filter it was suddenly much stronger, but the gradual blocking that the filter encounters is sneaky and little by little takes away your pressure and by the time you notice it's not quite as perky as it usually is the clogging is pretty massive.

One thing not mentioned much about gas mileage is how the aerodynamics play such a Major part as drag is the No.1 load at highway speed. I noticed an increase in mileage changing the stock windscreen to a Puig DB, then another bump changing that for a ZG Touring version. Mine seemed to say the screen is worth several mpg's going from stock to the larger touring one so it must be cutting through the air easier.

Without a Yosh-Box or TEKA, you're left with the myriad of piggy-back tuning boxes if you want to change the mixtures and they do seem to work fine though at the added expense and complexity of an add-on device.

A question: Does your bike have an O2 sensor? If so, they sometimes contribute to poor economy and might be worth a try to unplug just to see if it makes a difference.

Right, bike came from the workshop, here's what's been done:

• Replaced airbox with brand new
• replaced stock air filter with KN
• new spark plugs
• valve adjustment
• new radiator
• new radiator hoses
• injectors sent for cleaning, measured and within normal operating parameters
• Fuel pump throughput measured and within parameters
• new fuel lines
• new spark plug wires
• changed most fuel lines
• oil and oil filter
• ECU stock mapping reapplied (just in case)
• O2 sensor eliminator installed
• verified no TRE/ATRE installed

Result: NO RESULT. Reserve light still comes up at 140+ km.

Consumption still at 9 liters/100km or 28 mpg.

Right now, and correct me if I'm wrong, it's either down to faulty TPS and/or ECU mapping (???)

Rob, could I possibly have a copy of your ECU mapping, in form of a file perhaps? If nothing else just for testing.

Also, I've spoken with a Suzuki parts dealer and they tell me that there are 2 TPS sensors... is this true?

 

[RecoilRob]

They might be thinking about the STV position sensor as the other TPS...though it wouldn't have much to do with the fuel mileage potential.

ECU I've been running lately is mapped with TEKA to: idle -15, 10% -45, 25% -50, 50% -40, 75% -20, and 100% left to stock. It would idle just fine with much, much less fuel and took -30 or more to see 14:1 A/F but seemed to idle a bit hot in warm weather so I added some back and this did hurt the mileage some.

How fast are you riding? Set as above, mine will cruise at 65-70 over 50mpg (US) but if a lot of throttle is being used...well, you've got to feed the horses. At full throttle the instantaneous consumption drops well into the 20's...so if you're riding like a loon...GREAT! But if you're actually riding trying to conserve fuel...that's not so good.

You haven't mentioned gearing....mine runs 18/40 which corrects the speedo, though last summer it ran 18/42 (just a bit taller than stock) to slightly over 50mpg ave. If the gearing is really short...that could hurt your mileage potential. Short trips? Every cold start eats several mpg's from your ave.

 

[bikerpete51]

MPG

Yep,
If you want fuel economy get an NC700/750 not an SV.
Mind you 28mpg is bad even compared with mine +/- 40 mpg in general use.
I find its my own fault I get less mpg as I just love that SV sound, especially accelerating hard and shutting off in a low gear- like a giant snoring-they just sound too good..
Sorry that doesn't really help with your problem. It sounds like you've checked or addressed most of the things which would affect economy.
The only thing left is an LPG conversion...

 

[coz]

They might be thinking about the STV position sensor as the other TPS...though it wouldn't have much to do with the fuel mileage potential.

ECU I've been running lately is mapped with TEKA to: idle -15, 10% -45, 25% -50, 50% -40, 75% -20, and 100% left to stock. It would idle just fine with much, much less fuel and took -30 or more to see 14:1 A/F but seemed to idle a bit hot in warm weather so I added some back and this did hurt the mileage some.

How fast are you riding? Set as above, mine will cruise at 65-70 over 50mpg (US) but if a lot of throttle is being used...well, you've got to feed the horses. At full throttle the instantaneous consumption drops well into the 20's...so if you're riding like a loon...GREAT! But if you're actually riding trying to conserve fuel...that's not so good.

You haven't mentioned gearing....mine runs 18/40 which corrects the speedo, though last summer it ran 18/42 (just a bit taller than stock) to slightly over 50mpg ave. If the gearing is really short...that could hurt your mileage potential. Short trips? Every cold start eats several mpg's from your ave.

Right, new info: I've checked/replaced almost everything now bar the TPS. No changes in consumption, although the engine now runs smoother. 30% City riding where I rarely (if ever) use more than 10% throttle. 70% highway riding where I cruise at roughly 90 miles/hour.

I asked my mechanic about gearing and he says it's stock.

One thing: I changed the spark plugs 2 weeks ago. Checked them yesterday and the rear cylinder one appears to have blackened considerably more than the front one. I know that this points to rich mixture, but why only on the rear cylinder?!?! Any ideas?

and another thing: my SV is 2003 model. Does this mean it has poorer/different electronics/sensors/ECU than the later models, therefore poorer economy ??

 

[RecoilRob]

The K3-4's are different than the later bikes, but not dramatically so. One thing that did change was the snorkel length on the later versions was shortened as it seems the early one proved to be a bit too long.

Now that we see the 'how' of your riding...I'm a bit confused as to just why you're worried about the economy? What do you expect it to do at 90 mph?! Aero drag increases at the cube of velocity (I think) so going from 50 to 100 increases the drag 4 fold...and a LOT of fuel is needed to push through the atmosphere. Even a 250 Ninja is going to struggle to get 30 mpg's at 100...if it even can.

We've got about a foot of fresh snow here right now, so I can't go out and see what the mileage is like at 90...but I do know it's nowhere near 50 mpg like it can maintain up to about 70. After that things go downhill pretty fast.

There likely is nothing wrong with your bike besides the person riding it. I say that with all fondness and am not judging how you're riding....just saying that if you want to improve your mileage, you're going to need to slow down a bit. Try limiting yourself to 70 and you should see an improvement. Putting on a Touring height windshield will also help with the high speed aero if you don't want to tuck...but don't expect more than a couple mpg's improvement.

Gearing it up to 18/40 should help a bit too...as will leaning out the mapping, but still the high speed mileage isn't going to look all that great when comparing against people who are actually riding TRYING to maximize their economy. The bike is running well, so enjoy it!

 

[schmidt314]

Aero drag increases at the cube of velocity (I think) so going from 50 to 100 increases the drag 4 fold...and a LOT of fuel is needed to push through the atmosphere.

The drag should be a quadratic function not cubic. As you do state though, doubling of the speed does then produce 4 times the drag (This is a quadratic relation). Just think about this kind of problem with the BloodHound Project... Mind boggling

-MS

 

[coz]

No offence taken, obviously, we're all friends here

However I find it hard to believe that riding a motorcycle (or any bike with a 17-liter tank for that matter ) at exactly 50% of its rev range (5500 rpm in my case) would result to 87 miles travelled distance before the reserve light comes up. Which is exactly what's happening in my case!!!!

Plus, after your yesterday's reply, I did a steady run at 4000 rpm on a highway for testing purposes. Distance travelled before reserve light: 93.2 miles hmy:

Now, you've been overly helpful to me and I'd hate to take up more of your time in what seems to be a dead-end issue... On the other hand I do mean to get to the bottom of this, even if 'this' means the bike runs fine and I'm riding it like a lunatic . On the other-other hand I did own a ZX-636 and I did ride it like there was no tomorrow (license revoked twice, bike confiscated for 6 months) and I still got better mileage than this. So if you could bear with me for just a bit longer and answer a couple more questions for me I'd be much, MUCH obliged!

1. Why would the back cylinder run on a richer mixture (inferred by the rear spark plug blackening in a course of 2 weeks), and how could I troubleshoot?

2. These percentages "idle -15, 10% -45, 25% -50, 50% -40, 75% -20" refer to rpm, right? The minus numbers what do they refer to? Is it also percentages or absolute values linked to the mixture ratio?

3. In absence of an A/TRE, the ECU uses modified mappings for the first 4 gears and up to 50% throttle, right? How does this behavior affect or is affected by the customized mappings?

4. TPS: to what extent could it influence consumption and is it worth installing a new one preemptively?

 

[bikerpete51]

MPG

Fuel up today: 36.5mpg.

 

[RecoilRob]

1. Why would the back cylinder run on a richer mixture (inferred by the rear spark plug blackening in a course of 2 weeks), and how could I troubleshoot?

2. These percentages "idle -15, 10% -45, 25% -50, 50% -40, 75% -20" refer to rpm, right? The minus numbers what do they refer to? Is it also percentages or absolute values linked to the mixture ratio?

3. In absence of an A/TRE, the ECU uses modified mappings for the first 4 gears and up to 50% throttle, right? How does this behavior affect or is affected by the customized mappings?

4. TPS: to what extent could it influence consumption and is it worth installing a new one preemptively?

VERY good questions! I'll try to answer them in order. 1. The front and rear cylinders share an exhaust system that gives them an unequal shot at the pipe lengths being as the rear is so much closer to the exit. We can't do pulse tuning like an I-4 with the 90 L-twin firing order, so the primary pipe lengths about all we have to play with..and the rear cylinder gets the short end of that stick. Small variances in cam timing make big changes in how things interact (at least IMHO) and with this in mind I timed the rear cams a little differently than the front...by half a degree, just hoping it would help balance them out a bit better. By design, many exhausts use differing length primary pipes to broaden the torque curve, and this no doubt is in play with the SV with the front working better down low.

2. TEKA numbers refer to throttle percentage opening, and the minus is a relative number that I don't believe is actually a percentage of the fuel...just a reference number. Not remembering right now if you can go over 100% with any adjustment because there ARE limits as to what the ECU will tolerate within the stock maps. Watching the A/F as the adjustments were being made showed that taking -50 did lean it out..but not like taking half of the fuel volume would do..so I think it's just a reference number. I could have gone leaner on mine..and did, but went back to what still felt 'good' and didn't heat up so much at low revs in traffic. Seems that fuel is being dumped to help control heat..or at least it looked like that to me.

3. The TEKA adjustments look like they affect the entire map, so any changes per gear will be in play. I was wanting to get a flash program so I could fine tune everything in the ECU, but after doing the TEKA....it looks like there isn't much more to be had and though it would satisfy curiosity about the ignition maps I don't believe it's worth the effort or costs to do more than TEKA tuning it. The stock ECU is VERY dependent on the Intake Air Pressure sensor/s...you have one while the latter bikes have an individual sensor for each cylinder and the ECU can alter fueling for each by watching the pressures. This might be a reason the later bikes could possibly do better fuel economy wise, and the TEKA also allows/permits you to adjust fueling for each individual cylinder should you feel the need. Be sure your vacuum lines are healthy and 'T'd together properly to the IAP sensor as it's the primary load sensor at play and a slight leak would lessen the vacuum signals and cause richer running. You have a cam sensor on the rear cylinder to tell the ECU where the engine is in its' operating cycle so it can inject fuel accordingly, while the later bikes has the ECU watching the IAP sensors for the vacuum pulses that identify the proper intake phasing. Any changes in mapping for each gear doesn't seem dramatic to me, and might be more for noise and exhaust emission compliance than any needs of the engine running. I DO think the gear changes how the STV's operate more than the ignition timing, and found the engine seems to like the 4 degree advance when otherwise stock. Once the squish is brought down to 1mm, and compression raised to 12.5:1 it tolerates the increased lead but really didn't seem to need it anymore...so I put it back to stock timing. The top-end hit does seem harder with the timing retarded back to stock too.

4. The TPS is also VERY important to how the engine operates, though as long as it works smoothly and is adjusted properly I can't see how it's going to help much. In Dealer Mode the little line will switch from the middle to top position as you open the throttle. Be sure it reliably goes down to the middle when you let off the throttle...and then switches up before 2000 revs or so. Mine was set around 1750 from the factory and has been smooth running from day one. Of course, this also depends on TB synch being correct and well balanced, which in turn relies heavily on valve clearance adjustment. My first check found all the valves perilously close to the tight limits...so I loosened them all to the wide end of the range, and was very surprised to find the idle 300 revs higher afterwards! Opening up the valve clearances does change the cam duration a little, and perhaps 4 degrees of overlap change can happen going from one extreme of the tolerance to the other. The stock SV cams are not super gentle and feed the engine well in stock displacement form, so altering the clearances is one way to fine tune how you like it to run. Want better mileage? Loosen them up and it 'should' respond a bit better at light throttle settings. When running the PC III, the 'Alpha-N' mode watches throttle position and revs...which is what the stock ECU also uses for high rpm/heavy load running. But at light throttle, the IAP sensors come more into play with 'Speed Density' type operation designed for smoother and more economical running. I'm not sure (never had a PCIII) but it sure looks like they don't work in SD most of the time. Though...it seems they have a newer version that won't allow changes below 4500 revs or thereabouts so perhaps that one still keeps the SD operation alive.

There is always the chance you you have a faulty injector on the rear jug that isn't spraying properly which will hurt how the fuel is atomized and thereafter burned. Might be worth a try to switch them front to back and see if the black plug follows. Mine burn both about the same...though when stock mine did carbon up something terrible as it was running SO rich. Yours consuming fuel as it is might be indicating a carbon fouled condition too...so perhaps some Seafoam treatment (or whatever you guys use) to make sure it's not heavily carbon fouled might be in order. Do you have access to a borescope? Quick look down the sparkplug should show you the piston top and chamber to see if the carbon is thick. Mine was like 1.5mm in places!!! Since the Wiseco change and lean mapping it's been running nice and clean-er. I don't know how much better you can expect it to run, but remapping to the TEKA settings above I could almost guarantee will make it better. And I believe you when you say you barely give it any throttle! When they're running full power (or richer) mixtures at light throttle they feel super responsive and make tons of power at barely cracked throttle. Once jetted down like mine is now, it's still responsive but needs much more opening to cruise compared to before.

 

[coz]

Thanks so much for your detailed answer Rob.

In the meantime progress was made!!

As it turns out, the mechanic that serviced my bike thought it was a good idea to enrich the fuel mixture in the low RPM range... without telling me!! Despite the fact I specifically told him that we're essentially troubleshooting a high consumption issue!!! He is an official Suzuki workshop and according to him, low-end range is up to 5000 rpm. So he'd set the mixture for this range to +5 whatever this means.

The reason he did it in the first place was the fact that I had complained about throttle jerkiness below 3500rpm and a choking sound coming from the airbox when going from zero to 5-10% throttle in the same rpm range. To be honest, this problem was fixed by the +5 setting, but at the time I attributed it to the general service.

Well to cut a long story short, I had him switch back to stock and presto! 6.7 liters / 100km, or 35.16 MPG (US).

I AM SO HAPPY (w00t)(w00t)(w00t)(w00t)(w00t).

However the jerkiness, the choking sounds and the occasional switching off when trying to accelerate from a stop, all came back. I'm willing to attribute these to the K&N filter and the Yosh race cans... I'm considering a Power Commander V and a dyno run to smooth everything out.

I also changed the front sprocket to size 18 today, and I can't wait to see how this affects consumption. However I haven't noticed a change in speedo reading... shouldn't it be affected ??

 

[RecoilRob]

Well....glad that you're finally getting somewhere! But it also is becoming obvious that your 'Official Suzuki workshop' might have a few things to learn about this particular bike. This is NOT out of the ordinary as many/most enthusiast forums end up knowing their machine better than a technician who must work on the entire line....and there are people here who KNOW the SV!

Anyhow...back to the bike. The throttle behavior you describe is almost certainly caused by the TPS (Throttle Position Sensor) being out of adjustment. To check: Put bike in Dealer Mode which will show -C00 in the cluster (if no codes are present...-Cxx if they are) and notice the dash before the C. It MUST be in the center when the throttle is at idle, then very slowly bring up the revs and watch for it to switch to the upper position which then tells the ECU that the throttle is off of idle. Most likely yours is not switching in the 1600-1750 rpm range where it should be for best drive-ability. Many end up over 2000....which WILL cause an instantaneous lean problem when the throttle is first moved because the ECU has no indication that it needs to add fuel...and also why your mechanic fattening up the bottom end helped your problem. Right idea...wrong way to implement it.

The speedometer watches the counter-shaft sprocket so no gearing change will affect the rpm/mph relationship like it would on a bike that watches the wheel rotation. Just keep in mind that your speedometer will now be pretty close...vs it being maybe 5%-9% fast and the odometer is going to now be reading slow...so take that into your calculations of fuel economy if you want to see the real #'s. Of course, you can ignore it being a bit slow and be confident that you're getting better than you calculate.

The K&N doesn't really affect the A/F ratios as far as I can see on mine, though it DOES make mine run noticeably better with increased fuel mileage along with more power. The intake restriction meter only shows just the tiniest amount of restriction difference going between stock and K&N's...neither being very much at all. It is just barely enough to pull the gauge to the first ratchet notch which is well below 2" H2o so the increase in performance I attribute to the flexible frame on the K&N helping the internal vibrations which are a tuned component...especially at low rpm and light throttle.

While we're talking about TPS settings...keep in mind that the valve adjustment is critical to both jugs creating the same idle vacuum signatures. Going from tight to loose (while staying within the allowable specs) will change the duration maybe 2 degrees...so tight to loose on both will change the overlap period better part of 4 degrees...which WILL change the idle vacuum. The Synch procedure is designed to make both Throttle Bodies respond identically and the adjustment will correct for 'slight' differences in vacuum signatures...but can only go so far. The adjustment settings are plenty for an engine with 'in spec' valve adjustment, but I don't like having either jug set differently so both will run as close to identically as possible.

Just day before yesterday I checked and adjusted the valves. Every one was fine except one intake a little too tight. This means all took the .006 but not .007 feeler except for the tight one which took .004 but not .005. These are all well within the allowable specs and some will mock me for worrying about it...but I want them all within .001" if possible. And...it IS possible. Synch the TB's AFTER setting the valves, then set the TPS as the last thing you do. The order is important!! And once everything is set properly I'll wager that your stumbles will be totally gone and your fuel mileage will increase.

Your mechanic could also easily take several times as much fuel away from the light throttle settings as he added before which will only make the mileage better and if everything is adjusted well the rideability will be excellent. VERY glad you're finally getting somewhere!

 

[bikerpete51]

MPG

Filled up today.. 40.5 mpg

 

[bikerpete51]

MPG... Holy Cow, how did Suzuki do it?

Well, I've just got back from a trip to Scotland to visit my mum and sister, and it's made me look at the SV in a different light...
I recorded all my petrol purchases and the odo readings when filling up and I've just entered it all on fuelly and....
Best ever MPG.. wait for it... 65.2 MPG!
Thats not a fluke either, as I also recorded 64.6, 61.7 and 63.8 in some sections. I also had a few lower ones of 48.4 and 52.7 when going into a strong headwind coming over Shap Fells down the M6. The bike was loaded up heavily as well with panniers, topbox, tankbag and rear pack with my heavy lock and chain, tools, and a full 5 litre container of petrol.
I would find it hard to believe if I hadn't done the fill ups and the riding myself!
I wasn't hanging around either with speeds between 70 and 108 mph, averaging around 80-85. The SV ran like a swiss watch, getting better as the miles piled on.
Has anyone else got similar mpg's on similar long journeys?
Total miles were around 850.
I think a plug chop is in order soonest to make sure it's not running too weak.

 

[schmidt314]

Well, I've just got back from a trip to Scotland to visit my mum and sister, and it's made me look at the SV in a different light...
I recorded all my petrol purchases and the odo readings when filling up and I've just entered it all on fuelly and....
Best ever MPG.. wait for it... 65.2 MPG!
Thats not a fluke either, as I also recorded 64.6, 61.7 and 63.8 in some sections. I also had a few lower ones of 48.4 and 52.7 when going into a strong headwind coming over Shap Fells down the M6. The bike was loaded up heavily as well with panniers, topbox, tankbag and rear pack with my heavy lock and chain, tools, and a full 5 litre container of petrol.
I would find it hard to believe if I hadn't done the fill ups and the riding myself!
I wasn't hanging around either with speeds between 70 and 108 mph, averaging around 80-85. The SV ran like a swiss watch, getting better as the miles piled on.
Has anyone else got similar mpg's on similar long journeys?
Total miles were around 850.
I think a plug chop is in order soonest to make sure it's not running too weak.

What is your gearing? If you are geared down from stock the odometer reads high and could be giving artificially high MPG.

Are your results in U.S. gallons?

-ms

 

[bikerpete51]

MPG

Bike has 2 teeth up over std on rear sprocket. (42T) but I still consider it to be overgeared compared to most bikes I've owned.
I've recorded litres and converted to UK gallons (divide by 4.5)
So, yes, maybe an error of 5 or 10 percent but still very good mpg's, especially for those speeds. In view of my town mpg of 36-40 I was also carrying a spare 5 litres of fuel, which I now know to be no longer necessary.
It would seem to indicate the fuelling is very rich at lower engine speeds and maybe a little lean at bigger throttle openings.

 

[bikerpete51]

MPG .... more...

Well looking at my trip B giving total miles I see it's well over the theoretical mileage at 940. From distances garnered from the AA route planner and known distances to places I went total miles was 873, so the extra teeth and intrinsic speedo error amounting to 7.6 % on the odo.
If I use the theoretical mileage and the fuel used it comes out to a more realistic 53.06 MPG.
Still pretty good I think..
And at that economy tank range is a decent 200 miles...
and my cruising speed of 85 mph was actually 78...

 

[bikerpete51]

Jeez... time for an NC750...

Well I've been commuting back and forward across town.. to and fro to Poole harbour a journey of only a few miles while I've been learning to windsurf.
Fuel consumption has been badly hit.
A new low record of 30.1 mpg.
I'm thinking that when I do the TPS reset things will improve since my line was already on top, meaning that the extra fuel is being added from tickover..
Does anyone know if this is correct?

 

[RecoilRob]

The line should reliably and repeatably go to the middle position when the throttle is released back to idle, so if it's set too high it sure won't help the mileage potential. If set too low the throttle will get boggy off idle, so something around 16-1700 for the switch seems a good setting and will allow good response and smooth running.

Watching my FuelBot demonstrates painfully how bad each cold start hurts the mileage average. I normally let it warm up to 100F before setting out...and this can remove several mpg's from the average each time, especially early on in the tank. So running many short trips is going to really kill a high mpg number and there's little that can be done about that mechanically I'm afraid.

My work car ('09 KIA Rio5) will easily deliver low to mid 40's on a highway run...but going back and forth daily to work about 5 miles away it won't hit 30 unless I get some highway running inbetween daily work runs. Basically....if someone is running mostly city type stuff, the mpg's you get are only a curiosity and really not worth checking because it won't show the potential of the machine at all. Warming up the lump takes fuel...even if you set out immediately after starting it's going to consume a bunch more than after it's been run a while and is up to temperature. But DO set the TPS please as it'll no doubt help and cannot hurt you.

 

[bikerpete51]

Walking the SV line

Thanks Rob.
I will be doing it shortly and fitting my 16Tooth sprocket.
I know the bikes capable of 50+ on a run as per my trip to Scotland when I was getting over 120 per tank, but 77.5 is the lowest I've had so far even on short trips. Thinking of buying a 400 Burgman for short hops around town.