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8l/100km on a CBR600f4i?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by grue, Jun 10, 2010.

  1. Hey guys,

    Even with a fresh air filter, my CBR is really a thirsty little pony. My last fuel-up 20 minutes ago calculated out to 8.3l/100km. Now that's by far my worst, but I've had a lot in the mid-high 7 range. These tanks are pretty much all city riding with lots of stop and go, and I'm a big guy, but I'm still concerned.

    I've got new spark plugs waiting to go in, is there a chance they might help with this? I don't know with any certainty that the bike NEEDS them, but after seeing the state of the air filter I'm not going to hazard a guess on how long it's been since the previous owner did them.



    Any other suggestions on what I should check?

    EDIT: One other thing that occurred to me… I'm having the cam chain tensioner replaced tomorrow, and because the noise is so damned annoying I haven't really revved the bike much above 4000-5000rpm when it's warmed up, so maybe I'm opening the throttle a lot more in lower gears for longer times to get the speeds I want? Sorta thinking out loud I guess, but not sure what the effect of higher throttle at lower revs is like compared to.
     
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  2. That seems way too high, even for a big guy who is using a lot of throttle at low engine speeds. My twin is considered thirsty (by me) at a worst of 14km/l so less than 12km/l is pretty crappy.

    New plugs *should* help, but only if they're knackered. Has anyone played with the mapping by using a PC or similar?

    It'll be interesting to see what happens when the cam chain is fixed and you use the full range of engine speeds and gears.
     
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  3. Yeah, I'm hoping to find that the plugs are completely shit, because it'll make me feel better :rofl:
     
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  4. Are you traffic light GP-ing it?
     
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  5. I'll give it a solid twist from time to time, but it seems like my average time to 60 is around 5-6 seconds by my count. I'm definitely not pushing very hard. I ride first gear until about 45, then second to about 55, then double upshift when I hit 60
     
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  6. how many kms are you getting before the light comes on?
    mines stock with the exeption of an air filter and a pipe. and i can get anywere from 180-220, depending on how i use the throttle.
     
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  7. When was the last time the throttle bodies were synchronized? (FI Sync) Might have something to do with it.
     
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  8. Last night was 155, but usually in the 160-175 range for tanks where it's mostly just been commuting.
     
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  9. My F4i is stock standard. Even prior to cleaning the spark plugs and air filter (they were both still in good nick, so only need a clean and gap check etc), as well as an oil change, CCTL change (the original one turned out fine but I replaced it anyway) and valve clearance check (all good), the thing was giving me around 5L/100km - but I do ride it in fairly high gears, even around the city, with the odd squirt on the open road. it's now running around 5L/100km ie. no change!

    The F4i is not known for its frugality, but it isn't a massive drinker either when commuting, so it's worth a dig into the service manual and see what's going on. I would suggest riding it like an old geriatric for a while (aka like me ...) and see how it goes, and especially riding out in the open roads for a day. If the bike's been modified in any way (chip etc), that would be where I'd look.
     
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  10. Oh, I regularly get about 250km before the reserve bar lights up, and I've ridden with the final fuel reserve bar (there's 4) blinking close to 300km .... so according to my calculations at a conservative 5.5L/100km, I can probably ride to 300km before a refill.
     
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  11. Hmmmm… well, the bike does have a slip on Micron exhaust, but I don't think there was any ECU stuff done by the previous owner. I'm at 45,000km right now, so maybe I'll have the 48,000km service done a bit early and get everything checked out.
     
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  12. Throttle bodies , check that they are synched...... Im commuting, and the ZX14 is showing 6.6l/100km atm......

    something is definately wrong.

    OZ
     
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  13. Would the fact that my commute is very short potentially have anything to do with this? I'd say it's about 10-15 minutes each way, a total of a hair over 5km.
     
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  14. Worth looking at your actual usage pattern.

    I took some notes on my daily commute through heavy inner city traffic and it worked out at about six minutes of actual movement (below 60kmh) and 16 minutes at standstill (thanks, Vicroads). With fuel going through it all the time, the km/L figures are pretty meaningless in those conditions.
     
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  15. Good point. I bet I'd be around a 3:1 doing-nothing:riding ratio myself. I'm heading up to E2W in about 90 minutes to get my CCTL done, so I'll see how that affects my gear usage.
     
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  16. Definitely - a cold engine is NOT a frugal one. The internal parts need to warm up properly to give good performance, and the oil needs to get to its optimal operational temperature as well. A cold engine will not give good fuel economy, and stop-starting it will only make that worse.

    I would recommend a weekend test where you fill up with premium, set your counter to zero, and go for a good ride until you hit reserve. You'll probably be surprised.

    If it makes you feel any better, I'm doing around 5 to 6km/litre in my Valiant. My commute is also short, but not congested. The best I've gotten out of it is 8.5L/100km, the average around 10~12L/100km on the highway, and my worst was just above 4km/litre. Nothing beats retro, fuel-sucking yank tanks though :D

    Cheers - boingk
     
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  17. Has anyone mentioned checking your bike's economy on a highway run? Get out a ride for an hour at highway speeds. That will confirm whether you have poor economy and by the sounds of it, the bike would probably appreciate you blowing out the gunnels with a long ride.


    My 9R gets around 17 - 20km/l typically with a mix of city and freeway kms - so I would hope a 600 cc FI bike would be more efficient. That's about 5.8l/100km or better. On the track and caning it I've got as high as 7.5l/100km lol ...Grue, you must be track day attacking the traffic. :twisted:

    Cheers
     
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  18. My 600 was no more efficient than the 929 I replaced it with. I'd assumed that Grue was doing a normal run, not a 10m ride.

    On the track, I'd managed to get the 1000RR down to 90km before the fuel light went on, down from around 220km in normal use. :)

    And you know what a drinking problem the Aprilia has when riding with you guys!
     
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  19. I'm guessing at the exhaust. If the engine breaths significantly better and the carbs haven't been adjusted to account for that they will draw more fuel through - won't they?
     
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  20. hmmm i might look at getting my tb's synced.
    how dose one tell if the CCTL require a change?

    would an remus pipe and a ITG air filter decrease economy?
    my F4i has done 35thou and i cant get anywhere near 250kms from a tank.. the best ive had is 220 and that's with the gauge at the minimum... (put about 15l into it)
     
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