zx12r fuel economy

[98ninja]

ok at 208kms filled it and it took 16 litres.
there was one bar and it hadnt started to blink yet.
it springs to mind when im on stall patrol behind the girlfriend on her gpx250
she says shes doing 80 and my speedo says 70. so maybe the mileage and speedo are out 10%?
thats if the speedo and the odometer run off the same measurement. if they do then im getting 230 out of a tank.
long shot?

[chuffed]

My B model has a 19l tank and the last bar is 6l or 4l when it starts to flash. Around town 210 is pretty normal higway running riding sedately, standard gearing i managed 260-270k a couple of times while ringing its neck i've once needed to fill up before 200k. Even knowing that when its flashing i have 4l left i rarely let it get that low, pushing ya bike sucks, and like most 12 owners i never bought it for its fuel economy.

[fireyrob]

Dealer reckons 98 "may" cause it to ping.

That's usually the other way around Rob, with low octane fuel you'll get pre-ignition detonation or pinging. I'd be *very* surprised to learn that the inverse is also true.

Thats what I thought but was told with the carby set up that it was no good for it and it may ping at high rpm??? Is it possible that the chamber hasnt compressed the 98 enough to ignite it??? Im sooo confused

[Gosling1]

.....Gos how many times have I been to PI with the 12 now...6..maybe 8 times?
and its been pretty much the same each time . I fill at the servo just around the corner
from home and off I trot to the Island ...and just before I get home, the block starts
blinking and there is the servo...roll in and fill it, always the same, 17 or 17 and a bit
litres to fill it

12R tanks takes 20 and the gauge block is flashing with 3 litres left..so that sez the
gauge is pretty accurate

I know the PI run is mainly freeway so maybe the unchanging throttle setting gives
this fuel consumption result..who knows.....

Its the unchanging throttle for 145km each way, with revs under 4k that must do it !! I think my 05 only has a 19l tank ? maybe that counts for a bit of the difference........I would love to get 250k before the blinking started........ 290k's per tank........thats the stuff of dreams for the MFP12. But as some wise man said a bit earlier, you don't buy a 12 for its fuel economy....

...Thats what I thought but was told with the carby set up that it was no good for it and it may ping at high rpm??? Is it possible that the chamber hasnt compressed the 98 enough to ignite it??? Im sooo confused ...

Don't be. 98 Octane is really only needed for sports bikes that run a static compression of >11:1 ( as a general rule of thumb). If your bike has a c/r of anything lower than 11:1, then 95 octane is fine, and if your c/r is < 10:1, you can easily get by with normal unleaded (91 octane).

Pinging (engine knock, detonation) is a result of gases inside the combustion chamber being combusted abnormally - ie they are 'exploding' within the combustion chamber instead of being part of a 'controlled burn' or steady flame-front that expands around the spark plug. Pinging is more likely to happen at lower rpm than higher, especially if the engine is loaded, has a high static compression ratio, and is being fed lower octane fuel than what it would normally like to eat.

Hope that helps clear it up a bit ?? Detonation is one of those topics that can be discussed "ad infinitum' its an very interesting engineering issue.

[shinnynoggon]

gosling1 , your's is the same as mine , 19l , solid last digit 6l left , when starts to flash 4l

[98ninja]

i didnt buy it for fuel economy either
i was wondering whether there was something wrong or not.

[Smitty]

. But as some wise man said a bit earlier, you don't buy a 12 for its fuel economy....

and I didn't either.....

the Spur runs that i have been on with other members have required a fill about 2/3rds the
way thru at about 200-210kms...so I know what happens when all them kilowatts are enjoyed

cheers

Smitty

[98ninja]

what difference would an after market air filter make to the bike (non fuel economy related question)
and is there a recommended air filter?
almost bought a blue 12 a while ago and the guy swore by just the air filter increasing performance.

[QuickaKwacka]

In support of Smitty, I have the 03 model 12 with DNA filters, PC3 usb with custom map and a micron can and on my last trip to the Gold Coast kept records of the fill points and litres used, for the whole trip of 1,475 kilometers I used 91.51 litres of E10 giving an average of 16.118 kpl. When the dyno work was being done the dyno bloke said that the bike in stock form was running very rich, I was also only getting 200 kilometers per tank but now on highway cycle can easily get 290 and not have the flasher start up. (keep in mind that I am an older rider and tend ride at a constant speed with light throttle adjustments, even at higher speeds, on the last trip it rained heavily all the way home and was able to sit on $1.40 for most of the way). Having said that if you use the power for a bit of fun the you will empty the tank fairly quickly.


Regards
RonnieG

[Gosling1]

i didnt buy it for fuel economy either
i was wondering whether there was something wrong or not.

I don't think anything is wrong, this sort of mileage is pretty common.......

...what difference would an after market air filter make to the bike (non fuel economy related question)
and is there a recommended air filter?
almost bought a blue 12 a while ago and the guy swore by just the air filter increasing performance....

It makes almost no difference at all to the airflow. Maybe a couple of hp at the most. The main benefit of a/m filters is that they don't need replacing, just cleaning, and over the comparable life of several stock filters, you will get your money back easily. Putting a set of BMC filters in your 12 won't make it any more of a weapon than it currently is.......

....When the dyno work was being done the dyno bloke said that the bike in stock form was running very rich....

My dyno bloke said much the same thing. These babies all run pretty rich in stock form. On the first dyno run I did, the only mods were DNA filters and a Yoshi RS3 bolt-on can. These mods were enough to bring the a/f ratio down to almost spot-on, from the rich factory settings........

But I still struggle to get more than 220km out of a tank before that bloody blinking starts !!!!

[fireyrob]

PM'd Gosling but still v confused... Checked my owners manual and it definately recommends 91 octane... And the compression ratio of my little 250 is 11.6:1! Am wondering if having carbies v FI makes a difference as mine is Carby???

[chuffed]

Ronnie i cant believe that you run it on E10, the sticker on my tank when new said 95+ octane.

[Rusty]

There are a lot of factors that determine what octane fuel is necessary; compression ratio is just one. Others include bore, combustion chamber shape,size and surface condition, valve placing, head material and quality - the list is quite long.

For comparison, my ZZR600 usually runs quite cheerfully on 91. Compression ratio is 11.5:1.

My ZX9R sometimes pings on 95, but not usually (seems to depend on the servo). Compression ratio is 12.2:1.

The ZXR250 doesn't ping on 91, but because gets flogged unmercifully all the time I prefer 95. Probably not necessary. Compression ratio is 12.2:1 (yes, the same as the 9).

I'd be REALLY surprised if anything was pinging more on higher octane fuel. The only way it can happen that I can think of is if the fuel is not being burnt properly, which would leave carbon deposits. That could cause hot spots, and thereby contribute to pinging, but it'd still be worse on lower octane fuel.

It is likely that using petrol with an unnecessarily high octane rating will cause carbon deposits if tuning is not adjusted to suit. It can also cause the bike to be smoky on start up, particularly with the choke, and probably cause minor drivability issues including slightly increased fuel consumption.

In summary, go with the manual. If it pings, go up one step in octane. If it doesn't, enjoy the slightly cheaper motoring.

[fireyrob]

Ronnie i cant believe that you run it on E10, the sticker on my tank when new said 95+ octane.

Im pretty sure E10 fuel is rated at 95 octane!

In summary, go with the manual. If it pings, go up one step in octane. If it doesn't, enjoy the slightly cheaper motoring.

It seems to run fine on both. If anything its easier on the 98 as less throttle is needed for the slow speed stuff which is what Im practising before my P's test... So I guess Ill decide each time I fill! Thanx for the advice

[brendanzxr]

I 've tried all different octane fuel's on my zxr250c, and they all are fine for my bike , still not sure if it pinged or not, and i thrash it most of the time, but i also do slow cruising too , seem's fine, . But i'm still not sure what percentage octane fuel is better for milage. :?edit