Can I Squeeze Anymore MPG?
02-12-2009, 07:13 AM
#1
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Can I Squeeze Anymore MPG?
Rode with Hotbrakes and L8RGYZ yesterday, as the weather was warm and windy as Hell. As we stopped to refuel after a spirited ride we compared MPG and Hotbrakes was at 38, L8RGYZ was at 41 and I a lowly 33mpg and cannot figure out why. The bike seems like it is running a little rich, but I'm not sure what to address first. I did sync the carbs before the ride. Here are the particulars on what I have done to the carbs.
FP 1.0 carb kit
180 front and 182 rear
needles set at 4th from top
2 1/2 turns out on the pilot screws
K&N filter
In addition, I outweigh the two anywhere from 25 to 70# and was wearing a mesh jacket to their leather jackets.
Any ideas where to start my adjustments?
FP 1.0 carb kit
180 front and 182 rear
needles set at 4th from top
2 1/2 turns out on the pilot screws
K&N filter
In addition, I outweigh the two anywhere from 25 to 70# and was wearing a mesh jacket to their leather jackets.
Any ideas where to start my adjustments?
02-12-2009, 07:33 AM
#4
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I think the weight plus the mass protruding outside of the fairings is what does it. Maybe our bikes are still jetted stock or close to it so they are leaner. Could also be your right hand. If you were slowing down a little more for the turns then catching up on the exit you would be using more fuel. The slinky effect...I'll let you lead next time and we'll see if that brings the mpg's closer together. Its probably a combination of everything.
02-12-2009, 07:40 AM
#5
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02-12-2009, 08:18 AM
#7
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A spirited ride means 32-34 for me as well without being rediculous. 41 mpg if I stay at 3-4k RPM and accelerate like a peppy geo metro. Your bike sounds normal, and theirs sounds high to me.
02-12-2009, 08:28 AM
#8
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Next time switch bikes and see what happens.
Rider weight and aero have to have some effect, but 20% sounds excessive. Why are you using premium?
I weigh nothing and tuck really low on highway trips. 35 mpg on a spirited ride, and up to 50 mpg highway.
You can't really compare mpg though except with bikes on the same ride. Spirited for me might be a snoozefest for someone else.
Rider weight and aero have to have some effect, but 20% sounds excessive. Why are you using premium?
I weigh nothing and tuck really low on highway trips. 35 mpg on a spirited ride, and up to 50 mpg highway.
You can't really compare mpg though except with bikes on the same ride. Spirited for me might be a snoozefest for someone else.
02-12-2009, 08:35 AM
#9
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So it definitely wasn't the slinky effect then. Fagan said you were on his *** coming in and on it coming out.
87 should improve it by allowing the fuel to burn more efficiently. You could lean it out for higher octane fuel, but the gains would probably be negligible.
87 should improve it by allowing the fuel to burn more efficiently. You could lean it out for higher octane fuel, but the gains would probably be negligible.
02-12-2009, 08:57 AM
#10
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Reaper being heavier probably has to shift more as he is closer to stock... or is he's not, he's lugging it and that takes fuel...
If he is then running premium that means he is indeed running rich if it's setup the way it should be for 87... A VTR with a stock engine has no need for premium... it usualy only hurts MPG and pocket... No power benefit what so ever...
Start massaging the engine like some on here, and there might be gains...
So start by running 87 and see what happens...
Last edited by Tweety; 02-12-2009 at 08:59 AM.
02-12-2009, 09:18 AM
#12
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Trust me it makes a difference with gearing... Comparing L8RGYZ and you Hotbrakes I'd say the difference between the two of you is probably 50% the gearing in terms of MPG and 50% wrist if both bikes are tuned decently...
Reaper being heavier probably has to shift more as he is closer to stock... or is he's not, he's lugging it and that takes fuel...
If he is then running premium that means he is indeed running rich if it's setup the way it should be for 87... A VTR with a stock engine has no need for premium... it usualy only hurts MPG and pocket... No power benefit what so ever...
Start massaging the engine like some on here, and there might be gains...
So start by running 87 and see what happens...
Reaper being heavier probably has to shift more as he is closer to stock... or is he's not, he's lugging it and that takes fuel...
If he is then running premium that means he is indeed running rich if it's setup the way it should be for 87... A VTR with a stock engine has no need for premium... it usualy only hurts MPG and pocket... No power benefit what so ever...
Start massaging the engine like some on here, and there might be gains...
So start by running 87 and see what happens...
There was only a 3mpg difference between L8RGYZ and mine, but there is a 50 pound difference between us and our gearing is far from the same.
02-12-2009, 09:26 AM
#13
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Rode with Hotbrakes and L8RGYZ yesterday, as the weather was warm and windy as Hell. As we stopped to refuel after a spirited ride we compared MPG and Hotbrakes was at 38, L8RGYZ was at 41 and I a lowly 33mpg and cannot figure out why. The bike seems like it is running a little rich, but I'm not sure what to address first. I did sync the carbs before the ride. Here are the particulars on what I have done to the carbs.
FP 1.0 carb kit
180 front and 182 rear
needles set at 4th from top
2 1/2 turns out on the pilot screws
K&N filter
In addition, I outweigh the two anywhere from 25 to 70# and was wearing a mesh jacket to their leather jackets.
Any ideas where to start my adjustments?
FP 1.0 carb kit
180 front and 182 rear
needles set at 4th from top
2 1/2 turns out on the pilot screws
K&N filter
In addition, I outweigh the two anywhere from 25 to 70# and was wearing a mesh jacket to their leather jackets.
Any ideas where to start my adjustments?
It looks like your slide needle is set pretty rich. Your idle screws are also a little on the fat side too. You didn't mention what you have for exhaust, but unless you have major modifications I'd say your jetting is off.
That said, my bike only gets 33-35mpg. Are you sure those guys got that much? Did you use their speedos or actual miles? You mention that the gearing has been changed, so you can't use the odo for your measurements.
02-12-2009, 09:28 AM
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02-12-2009, 10:01 AM
#15
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I dont think that would affect the ODO readings.. Speedo/ODO arent driven from the transmission IIRC.. they are driven fron the rotation of the front wheel. Therefore, gearing wouldnt affect speedo readings.. just a different size tire would.
02-12-2009, 10:28 AM
#17
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Hotbrakes, yeah... But you said spirited ride... So then you are in the right powerband with your gearing, using what you have effieciently... getting decent mileage... L8RGYZ has stock so he's getting better mileage but less grunt/different gear...
I'm guessing you are heavier then him?
02-12-2009, 10:34 AM
#18
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Riding yesterday, I never got out of third gear and maintained the rpms between 5-6.5K on the backroads.
I have Yoshi slip-ons that the cans have been cut down to 14".
Premium, I thought everyone is using premium.
Jamie, any thoughts to baseline carb settings?
I have Yoshi slip-ons that the cans have been cut down to 14".
Premium, I thought everyone is using premium.
Jamie, any thoughts to baseline carb settings?
02-12-2009, 10:37 AM
#19
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It looks like your slide needle is set pretty rich. Your idle screws are also a little on the fat side too. You didn't mention what you have for exhaust, but unless you have major modifications I'd say your jetting is off.
That said, my bike only gets 33-35mpg. Are you sure those guys got that much? Did you use their speedos or actual miles? You mention that the gearing has been changed, so you can't use the odo for your measurements.
That said, my bike only gets 33-35mpg. Are you sure those guys got that much? Did you use their speedos or actual miles? You mention that the gearing has been changed, so you can't use the odo for your measurements.
I hear that ign adv will increase fuel mileage too, so do the guys with the best mpg have advanced ign timing?
RC
02-12-2009, 11:52 AM
#20
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I was doing 90mph around Lake Superior and had a huge tang bag plus a triple bag setup in the rear that limited me to a top speed of 130. I had +2rear and managed 43ish mpg. Spirited riding in the sense of passing cars non stop. I would look at your fueling and the manner in which you apply throttle.
02-12-2009, 11:57 AM
#21
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I was doing 90mph around Lake Superior and had a huge tang bag plus a triple bag setup in the rear that limited me to a top speed of 130. I had +2rear and managed 43ish mpg. Spirited riding in the sense of passing cars non stop. I would look at your fueling and the manner in which you apply throttle.
RC
02-12-2009, 12:10 PM
#22
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I also have a modified bike, but the one change that bumped the milage up 20-25% was to install a WORKING throttle position sensor and to set it correctly (assuming the ignition timing is correct to begin with).
Little things mean a lot.
Little things mean a lot.
02-12-2009, 12:47 PM
#23
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I had to grind my TPS to get the numbers that it should have for resistance. it made a little bit of difference, but the lightened flywheel really effects the bike as far as smoothness. I do not have ign advanced on the bike, and I do have a +1 front to get me close to stock ratio (good for 2-3mpg on a long trip). Two summers ago on the Lake Michigan go round I got 45mpg per stop. It is all how you ride it (plus my exhaust is the most effecient one ever made, I know cause I built it myself).
If you really wanted to change your fuel mileage, and give it down low grunt, get a set of adjustable cam sprockets and pull some overlap out of the cams. Granted you will lose top end, but if you care about fuel mileage, its a quick 3-5ish mpg.
If you really wanted to change your fuel mileage, and give it down low grunt, get a set of adjustable cam sprockets and pull some overlap out of the cams. Granted you will lose top end, but if you care about fuel mileage, its a quick 3-5ish mpg.
02-12-2009, 12:50 PM
#24
Remember stock is BAD!
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The compression ratio is so low on the superhawks that premium is not needed. But if you want to spend more $ at the gas pump feel free.
One thing that no one has mentioned is tire pressure. Have you checked your tire pressure lately?
One thing that no one has mentioned is tire pressure. Have you checked your tire pressure lately?
02-12-2009, 01:52 PM
#25
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This sounds strange, but it's true. Compare making 50 hp by running 8,000 rpms at half throttle, vs running it full throttle at 4,000 rpm, or thereabouts. Obviously, lugging isn't good for longevity of the engine, but that's a different story.
I don't think premium is really going to hurt fuel economy in any measurable way, but it won't help it.
02-12-2009, 01:56 PM
#26
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...without a throttle position sensor.
It did effect idle though.
02-12-2009, 02:08 PM
#27
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Actually lugging it is generally more fuel efficient. Throttling the engine down decreases fuel economy.
This sounds strange, but it's true. Compare making 50 hp by running 8,000 rpms at half throttle, vs running it full throttle at 4,000 rpm, or thereabouts. Obviously, lugging isn't good for longevity of the engine, but that's a different story.
I don't think premium is really going to hurt fuel economy in any measurable way, but it won't help it.
This sounds strange, but it's true. Compare making 50 hp by running 8,000 rpms at half throttle, vs running it full throttle at 4,000 rpm, or thereabouts. Obviously, lugging isn't good for longevity of the engine, but that's a different story.
I don't think premium is really going to hurt fuel economy in any measurable way, but it won't help it.
Lower end of the throttle without lugging it is by far more efficient... the throttle is still snappy, and you aren't induced to downshift...
Premium affects fuel economy... It's not used at full efficiency... Hence higher consumption... And add to that that the settings in this case is rich...
02-12-2009, 02:26 PM
#28
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Well I disagree. Making the same amount of HP at lower RPMs will always get you better mileage, in any circumstance.
Lower throttle requires more RPMs. I like to ride that way, because I can use the engine braking, and because I can tear up the canyons without shifting as much, but it really sucks down the gas.
Lower throttle requires more RPMs. I like to ride that way, because I can use the engine braking, and because I can tear up the canyons without shifting as much, but it really sucks down the gas.
02-12-2009, 02:32 PM
#29
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Well I disagree. Making the same amount of HP at lower RPMs will always get you better mileage, in any circumstance.
Lower throttle requires more RPMs. I like to ride that way, because I can use the engine braking, and because I can tear up the canyons without shifting as much, but it really sucks down the gas.
Lower throttle requires more RPMs. I like to ride that way, because I can use the engine braking, and because I can tear up the canyons without shifting as much, but it really sucks down the gas.
Same HP = lower RPM = better mileage... I totaly agree with you here...
But lower throttle is something completely different... Lower throttle = lower RPM, not the other way around...
Changing the gearing however means changing at what RPM's you have power...
02-12-2009, 02:36 PM
#30
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Also if you are lugging it it usually means your gearing is to tall... Hence why it leads to a downshift... And that burns more fuel than you saved for the few feet you where lugging it...
And this is why Hotbrakes is getting nearly as good mileage as L8RGYZ... He's geared for the way he rides, so he's at lower throttle in to turns, above lugging it... and got good power exiting without downshifting... (obviously different gear for fast and slow corners, but not going up/down all the time...)
And this is why Hotbrakes is getting nearly as good mileage as L8RGYZ... He's geared for the way he rides, so he's at lower throttle in to turns, above lugging it... and got good power exiting without downshifting... (obviously different gear for fast and slow corners, but not going up/down all the time...)
