Right, bike came from the workshop, here's what's been done: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, 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.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.
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 bogglingAero 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.
VERY good questions!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?
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.