'10 CBR1k: drastic drop in fuel economy

[Virt]

Ill start by saying I didn't buy this thing for fuel economy.

Bike: 2010CBR1000RR
Odo: 9,000ish km
Riding style: mostly 20 minute commutes at decent pace.

I recently preformed the 'flapper mod' on my bikes intake (removing 2 restrictor valves in the intake that normally open above 4-5k rpm).
I also did the 'flapper mod' to the exhaust as well (pretty much the same thing but in the can).

Since doing this I have noticed a massive drop in fuel economy, same style riding, but now instead of about 250kms before fuel light, I am only getting 180-200.
I find it a bit weird as it was such a sudden drop and I kind of expected it to improve economy if anything at all.
2 tanks so far, again, same style riding as before mods.

If anyone has any insight to this please let me know, I dont want to be riding around with a problem but if its normal then w/e.
Cheers!

[D'Artagnan]

Dyno, mapping update?

[milesiles]

Have not heard of this mod, where do I find out more? But yeah would say that ECM could over fueling to compensate for the extra air. Especially at idle where the flappers are usually closed.

Power commander/ custom map could be in order?

[wheresmybadger]

Done both of these mod's and didn't have any issues with using extra fuel at all

check
Honda CBR 1000RR Motorcycle Forums: 1000RR.net you'll get lots of answers to problems here or

Honda Motorcycles

also insturctions for the flappy mods are on both of these sites

Ill start by saying I didn't buy this thing for fuel economy.

Bike: 2010CBR1000RR
Odo: 9,000ish km
Riding style: mostly 20 minute commutes at decent pace.

I recently preformed the 'flapper mod' on my bikes intake (removing 2 restrictor valves in the intake that normally open above 4-5k rpm).
I also did the 'flapper mod' to the exhaust as well (pretty much the same thing but in the can).

Since doing this I have noticed a massive drop in fuel economy, same style riding, but now instead of about 250kms before fuel light, I am only getting 180-200.
I find it a bit weird as it was such a sudden drop and I kind of expected it to improve economy if anything at all.
2 tanks so far, again, same style riding as before mods.

If anyone has any insight to this please let me know, I dont want to be riding around with a problem but if its normal then w/e.
Cheers!

[Thirsty]

Well the 'flappers' would be improving your low down torque, particuarly the one in the can by increasing backpressure. If you only ride in the rpm zone before they operated, then the decrease in torque would require more throtle = more fuel. Im no tuner tho, so I have no idea if the EFI is doing its own thing.

[michael]

If ya bummed out by 180km range dont buy a zx10, Id be stoked with 200kays at a "decent pace"
I would have though any mods aimed at an increase in power would have decreased fuel efficiency? but yeah it does seem quite a signifacnt drop.


Michael.

[drifter]

i lost 10% of my fuel economy after fitting my pc3, but that's to be expected after looking at the map and seeing how much extra fuel is dumped in.

[JamieBlade]

Yeah I did both those mods too before I got my Yoshi and didn't notice any fuel differences. Is there anything else you've changed? Different fuel? 98 vs 95?

[wheresmybadger]

Are you sure you plugged the right hose of the air box when you did the air intake mod??

[Virt]

Haven't touched anything else, always used 98, no other mods, except here: Custom HID projector headlights with DRLs (Completed!) which is just lighting, I wouldn't imagine it has any effect as it ties into the oem wiring, no wiring mods.
PC3 and TaylorMade pipe in the future.
As I have only run 2 tanks through, I will continue to monitor it and post here.
My guess is more air = more fuel but then more power but then... argh!
Does anyone know offhand if the 1000rr has an auto-adjusting ECU?

[wheresmybadger]

Haven't touched anything else, always used 98, no other mods, except here: Custom HID projector headlights with DRLs (Completed!) which is just lighting, I wouldn't imagine it has any effect as it ties into the oem wiring, no wiring mods.
PC3 and TaylorMade pipe in the future.
As I have only run 2 tanks through, I will continue to monitor it and post here.
My guess is more air = more fuel but then more power but then... argh!
Does anyone know offhand if the 1000rr has an auto-adjusting ECU?

Yes its auto adjusting thats what the o2 sensors is there for as well as the air box temp sensor so that it can adjust fuel to suit

if its running rich or lean it will adjust it with in reason

[Virt]

I will double check the vacuum hose to see if its still blocked, I wouldn't imagine a vacuum leak would cause this though?

I removed the flap springs, the actuators, the solenoids and the vac reservoir, blocking only one hose, which was vac feed to the flapper system.

[filbert]

Does it sound better since the mods?

You would be surprised how much certain engine notes or crackling and popping noises can be majorly detrimental to fuel economy

I had a subaru forester that used more fuel than most v8s when the new muffler went on it was much more economical when it was quiet high rpm shifts or shutting off the throttle under full boost made some wonderful noises.

[wheresmybadger]

I will double check the vacuum hose to see if its still blocked, I wouldn't imagine a vacuum leak would cause this though?

I removed the flap springs, the actuators, the solenoids and the vac reservoir, blocking only one hose, which was vac feed to the flapper system.

yeah it probably wouldn't but if there is extra air getting into the air box it might play with the sensor and use extra fuel

bikes will use more fuel in winter but not that amount

it could be a spark plug problem but being a honda doubt that to

how long have you owned it, found the busa i had last time first 6000ks good fuel and tyre usage but after i got used to power and how much fun i had next tyre lasted 2000k's and the fuel consumption was awful
you

[Virt]

Thats quite true filbert
Ive had the bike since November last year, brand new, I could possibly be riding it harder since the nice noise its started making though I was making a conscious effort to try and ride the same for comparison purposes.
Thanks for the insight guys, some good ideas and some new things on my list to check, unfortunately I wont be doing any maintenance for a little while as im confined to the bike untill my 4wd suspension lift is finished (oh damn.. )

[wheresmybadger]

Thats quite true filbert
Ive had the bike since November last year, brand new, I could possibly be riding it harder since the nice noise its started making though I was making a conscious effort to try and ride the same for comparison purposes.
Thanks for the insight guys, some good ideas and some new things on my list to check, unfortunately I wont be doing any maintenance for a little while as im confined to the bike untill my 4wd suspension lift is finished (oh damn.. )

I've never given much thought to how many k's I get to a tank round the city.

Well cause lets face it I just like going nuts, but after reading this thread thought i'd give it a go, so kept track of the k's and took it slightly less open throttled then i normally would.

Not only found out that my light came on at 190k's but god it was boring way to do it.

So Virt, Can't be 100% but don't think there is anything wrong with your blade.

P.s won't bother trying to

[Virt]

Oh sweet, thanks for the info badger, appreciated
Possibly just over time the blade finds a nice middle point in fuel tables and stays there, who knows, Ill stop stressing over it

[lee]

you could always put it back how it was, and see if your fuel economy returns?

[Virt]

Thought about it, fair bit of work, my lighting mods take up all the space that was occupied by the system though.

[lee]

better keep the neons then ay bro