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Was talking to the parts guy at a local Kawasaki dealer today. Told him I was fixing to add the upgrades. He told me to expect a big drop in my mpg if I did. I was wondering what some of you guys experienced after your upgrades. I told him I expected a little I guess because of the right wrist problem associated with new power. He made it sound like much more than that. I don't remember seeing anyone here complaining....
 

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A drop in mpg yes, a big drop no, not if you do it right.
if you do the exhaust, a drop in air filter plus fuel programmer and you get say 10% increase in hp, you will be burning more fuel and air to make that hp.
so if your bike uses 15hp to drive it down a flat level road at a constant 50mph before the mods how many hp after? answer the same, so mpg will be very similar.
If you keep using the extra 10% hp you will of course use more fuel.
 

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I don't have any personal experience, but I have a good friend that put new cams, exhaust, breather, Power Commander, and new cams in his Nomad. It screams, and can keep up with almost any cruiser on the road. But, his fuel efficiency is almost non-existent.
 

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A drop in mpg yes, a big drop no, not if you do it right.
if you do the exhaust, a drop in air filter plus fuel programmer and you get say 10% increase in hp, you will be burning more fuel and air to make that hp.
so if your bike uses 15hp to drive it down a flat level road at a constant 50mph before the mods how many hp after? answer the same, so mpg will be very similar.
If you keep using the extra 10% hp you will of course use more fuel.
+1

It all depends on how much you use that right wrist. Some people have reported BETTER gas mileage (I suspect due to the bike running at a proper fuel mixture instead of EPA lean) after the big 3 when just cruising.

Obviously, if you've got it wide open all the time MPG is negligible.
 

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+1

It all depends on how much you use that right wrist. Some people have reported BETTER gas mileage (I suspect due to the bike running at a proper fuel mixture instead of EPA lean) after the big 3 when just cruising.

Obviously, if you've got it wide open all the time MPG is negligible.
+1... I love the power the big delivers. But, I have noticed cruising the highway a bit better mileage even at 70-75 mph. I am figuring fewer rpms to travel the same speed (vs stock).
 

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Discussion Starter #7
Thanks everyone. That's kind of how I felt it would be. More fuel consumption linked to the right wrist. Think I will proceed....
 

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Here are my numbers....
Before the big 3, consistently got 50mpg
After, consistently got 45mpg
Recently cleaned and re-gapped my plugs (from .032 to .036), cleaned and re-oiled my air filter, now consistently getting 48mpg
I do a variety of around town and highway riding, and really don't notice a change in mpgs...
Also a note: When I was first riding my bike stock earlier this spring I had a sport windshield on it....I no longer use it (been this way about 5000 miles)
 

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I think unless you get the fuel mapped very well you should expect a general decrease in mileage, regardless of the right wrist effect, which will compound the issue because you will be in the throttle more. After all, why in the world would someone want to spend all that money but then not use the result...regularly? ;)

I'm pretty sure my average economy went down just adding pipes because I like to hear'em sing now and then...like every time I drive it.
 

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I haven't done these mods but if you think about it the extra power comes at a price (gas & air). If you want the same performance after the mods then you use less wrist & therefore fuel consumption would be about the same. However - if you've done the mods then you obviously want to go faster & quicker than before so you use more fuel.
 

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Dunno...everyone seems to say the bikes run very lean. So, if you fix that by adding fuel to address lean mixture, it doesn't make sense to me how the fuel mileage could be anything but some degree less.

I do somewhat agree though that the wrist may be the bigger factor.
 

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Thanks everyone. That's kind of how I felt it would be. More fuel consumption linked to the right wrist. Think I will proceed....
I guess I am the only one that does not care about MPG/Fuel consumption on any Motorcycle, Jet skis, boats, cars or suvs I have ever owned ( Long list of each over the years ). To me it is the pleasure of riding or driving anything I have mentioned and enjoying it.
No, I am not rich... But feel I am here a short time and I might as well enjoy it. My opinion and two cents.
John
 

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I guess I am the only one that does not care about MPG/Fuel consumption on any Motorcycle, Jet skis, boats, cars or suvs I have ever owned ( Long list of each over the years ). To me it is the pleasure of riding or driving anything I have mentioned and enjoying it.
No, I am not rich... But feel I am here a short time and I might as well enjoy it. My opinion and two cents.
John
I knew someone would say this :D

MPG is a good diagnostic tool. A sudden drop in MPG without changing anything could indicate a problem, and could be the first warning sign that there's an issue. As mentioned earlier I've seen where MPG has saved an entire engine! A guy I ride with had a carbed Harley and his MPG dropped over a few days. He was smart enough to investigate why, and determined that both the petcock and the carb had leaks, and fuel was dribbling right into one of the cylinders. Slow enough not to cause an issue when ridden every day (other than poor MPG!) but if he wasn't keeping up with his MPG, then maybe it would sit for 3 or 4 weeks, the cylinder would fill with fuel, and that heavy duty starter motor would crank the engine, wouldn't be able to compress the fuel, and it would bend a rod.

Two ways he couldn't determined he was leaking fuel. Bent rod, or poor MPG. I'll take the latter!

And that's just one example. More commonly, MPG drops could indicate issues with ignition or fuel mixture.

Like you, I don't CARE what my MPG is, but I periodically check it to make sure everything is working the way it should!
 

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I knew someone would say this :D

MPG is a good diagnostic tool. A sudden drop in MPG without changing anything could indicate a problem.
Like you, I don't CARE what my MPG is, but I periodically check it to make sure everything is working the way it should!
I also agree it is a good diagnostic tool... I do check for that reason only on any gas engine with mileage or hours I own :)
But title of original thread is MPG drop after big 3 performance upgrades? I guess my statement should have said: When you are looking for more power or performance upgrades why would you care what it does to the MPG.
John
 

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I guess I am the only one that does not care about MPG/Fuel consumption on any Motorcycle, Jet skis, boats, cars or suvs I have ever owned ( Long list of each over the years ). To me it is the pleasure of riding or driving anything I have mentioned and enjoying it.
No, I am not rich... But feel I am here a short time and I might as well enjoy it. My opinion and two cents.
John
It's not my top priority but I do care that it is somewhat relative to what I'm doing and isn't needlessly crappy MPG. I think the latter is more the point.
 

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When you are looking for more power or performance upgrades why would you care what it does to the MPG.
John
To me this also makes a difference. If I'm going to do some sort of hop-up that gets me "X" more power I'm OK with a somewhat proportional decrease in economy. However, I'm probably not too interested if 10% more power costs me 50% less fuel economy.
 

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Mpg

Took a 200 miler short ride Sat. Some on the slap at 85 60% at 55 avg'd 50 mpg for the trip. I have Cobra 2-1 pipes power commander and an air intake...I think before I would have gotten about 53...
 

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Haven't done it to the bike, but I swapped intake/exhaust on my car several years ago. Got about 3 mpg better just driving on the freeway for 6 hours straight. I find that my mileage is directly proportional to the amount of "loud pedal" I apply.

Theoretically if you ride the bike exactly the same as you did before the swap, it should run more efficiently and produce more power per unit of fuel used. Of course, what's probably happening is you're using the additional power and thus more fuel.
 
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