Poor fuel mileage 57H
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Joined: Oct 2011
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From: MS
Poor fuel mileage 57H
My fuel mileage went to crap after my cam install. 2012 RK with decated head pipe, got my power commander and air kit from fuel moto and I am running his jackpot mufflers and a tune I got from him. Like everybody said the cam pulls like a freight train. I checked my mileage and I'm getting 29 mpg. Took a trip this weekend I almost ran out of gas and my buddy still had 48 miles left on his bike. Filled up at the same time twice. In a 100 miles my bike held a gallon more than his. He is riding a stock 2010 ultra limited. It has 103 motor same as my rk. Hell I might have to put my epa cam back in! What mileage should I be getting, I figgured at least 36 to 39 on the highway?
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From: wet coast BC
OP, what mileage were you getting before? what made you think you would get 36-39 Hwy. Have you stopped twisting the throttle enjoying the new feel and using extra gas to feel it.
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not entirely true...too much fuel will give less burn so less power...and you get unburned gas and byproducts fouling the plugs, valves and sneaking past the piston rings.
a cam with more overlap ( the period in which both valves are open) will allow raw fuel to flow from the intake thru the cylinder and out the exhaust
( that is why emissions says bad)....this can cause a mileage drop.
but as touched on above the settings in the tuner are likely causing the motor to run rich under some conditions...the complexity is such that it may for example be lean at 3000 rpms at a cruising throttle position, but be overly rich at 3000 rpms if the throttle is wide open or closed---or Vice Versa
All the sensor inputs must be balanced to work together under all driving conditions.
some tuners do not use the o2 sensors in which case the brain has no idea if the mixture is rich or lean or when- it just does what the map says to do.
I've been behind a few bikes drifting black smoke all of the place
OP, you'll have to get away from the canned map.
If you are dealing with FM, address your concerns to them.
while I do not use the dynojet products, FM has a great reputation
mike
a cam with more overlap ( the period in which both valves are open) will allow raw fuel to flow from the intake thru the cylinder and out the exhaust
( that is why emissions says bad)....this can cause a mileage drop.
but as touched on above the settings in the tuner are likely causing the motor to run rich under some conditions...the complexity is such that it may for example be lean at 3000 rpms at a cruising throttle position, but be overly rich at 3000 rpms if the throttle is wide open or closed---or Vice Versa
All the sensor inputs must be balanced to work together under all driving conditions.
some tuners do not use the o2 sensors in which case the brain has no idea if the mixture is rich or lean or when- it just does what the map says to do.
I've been behind a few bikes drifting black smoke all of the place
OP, you'll have to get away from the canned map.
If you are dealing with FM, address your concerns to them.
while I do not use the dynojet products, FM has a great reputation
mike
Last edited by mkguitar; Mar 22, 2015 at 03:21 PM.
not entirely true...too much fuel will give less burn so less power...and you get unburned gas and byproducts fouling the plugs, valves and sneaking past the piston rings.
a cam with more overlap ( the period in which both valves are open) will allow raw fuel to flow from the intake thru the cylinder and out the exhaust
( that is why emissions says bad)....this can cause a mileage drop.
but as touched on above the setting in the tuner are likely causing the motor to run rich under some conditions...the complexity is such that it may for example be lean at 3000 rpms at a cruising throttle position, but be overly rich at 3000 rpms is the throttle is wide open or closed. all the sensor inputs must be balanced to work together under all driving conditions.
some tuners do not use the o2 sensors in which case the brain has no idea if the mixture is rich or lean or when- it just does what the map say to do.
OP, you'll have to get away from the canned map.
If you are dealing with FM, address your concerns to them.
while I do not use the dynojet products, FM has a great reputation
mike
a cam with more overlap ( the period in which both valves are open) will allow raw fuel to flow from the intake thru the cylinder and out the exhaust
( that is why emissions says bad)....this can cause a mileage drop.
but as touched on above the setting in the tuner are likely causing the motor to run rich under some conditions...the complexity is such that it may for example be lean at 3000 rpms at a cruising throttle position, but be overly rich at 3000 rpms is the throttle is wide open or closed. all the sensor inputs must be balanced to work together under all driving conditions.
some tuners do not use the o2 sensors in which case the brain has no idea if the mixture is rich or lean or when- it just does what the map say to do.
OP, you'll have to get away from the canned map.
If you are dealing with FM, address your concerns to them.
while I do not use the dynojet products, FM has a great reputation
mike
My bike also had lousy gas mileage with a stage 1 set up. I added CAMS w/ a canned map ran great but still lousy gas mileage.
Since having the bike dyno'ed I'm getting better performance. A much crisper throttle response and the gas milage is the best it's ever been.