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Discussion Starter #1
Some time ago I read...I think in Motorcyclist Magazine...that a motorcycle gives the best gas mileage in the RPM range where the torque is maximum. Whether or not that is true I don't know, but my recent experience has been that I see better gas mileage when cruising in the 4000-5000 RPM range, rather than below 4000. This is mainly on country roads where my speed is in the 40-50 range, so I can cruise in 6Th gear at less than 4000 if I choose to. However it looks like by dropping down a gear or two, thus keeping the RPM's in the 4000-5000 range my mileage improves. Does anyone know where the torque curve for the 500 approaches it's peak?
 

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To add to that question...knowing the rpm for max torque, what is the optimal shift point for maximum acceleration? would it be just beyond the 8500rpms? I know plenty of you have raced these bikes and I'm wondering what your shift pattern is. also, is the the same for each gear? (aka 1st to 2nd...2nd to 3rd...3rd to 4th...)

Thanks,
Ken
 

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Both question are stuff I've been wondering about too. So far I'm not impressed with my mileage, the majority of my riding is on the highway in 6th at 6k, and I'm getting only about 40 it looks like. Wondering if going up or down with the gearing would improve on that.

And the time I've wound it out going for max acceleration I've shifted at redline, but it seems like the power really fell off just before 10k.
 

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Discussion Starter #5
Regarding your gas mileage, damarble...I have a 2003 Ninja 500 and I have regularly gotten above 58 mpg. The thing that prompted me to post my original question was I noted on my last tankfull I got 65, and I had purposely been cruising in the 4000-5000 range because I read other posts which talked about the power being much better once you get up to that range and higher. So I would suspect a problem if I got as low as you mentioned. Of course you may ride a lot harder than me, so that may have something to do with it...I'm just cruising down the backroads enjoying the scenery.
 

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Good thread that I'm hoping will provide useful experiences.

When I did my pilot jet mods on my '05 the factory had both sides set less than 1 full turn from the seated position. I started them at the 2.5 turn out & it's running too rich (by smell alone). I've worked my way down 1 full turn IN, in half turn increments & have not noticed any drop in smoothness or performance now that it'd 1.5 out from the seated position.

I'm not an agressive driver, & am using BP 10% gasohol... if that plays a role in this.
 

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A coulpe of comments: Milage has a lot more to do with throttle opening than RPMs, that said the extremes on both ends should be avoided. Use the gear that allows the smallest throttle opens to get the job done reguardless of RPM.
MaX preformance and best aceleration is had by keeping the engine around it HP peak of 9800 RPM So you want to shift about 10,200 so the reves drop only to 9200 or so. If you shifted at the exact power peak(9800) the revs would drop to less that 8700. the idea is to stay as close to the max powe point +- as little as possiable.

FOG
 

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I used to get about 40mpg on my bike. I noticed that my carbs were leaking a bit of gas, so I replaced the gaskets on the float bowls and the mileage jumped up to about 45mpg. (Note that my driving is almost exclusively city). The last trip I took (120 miles on the highway) got me about 52mpg. I don't ride that aggressively either, I usually stick to 4-5k for cruising and up to about 6k max when accelerating. Since some people get almost 60mpg out of their bikes I'm wondering what I'm doing wrong as well (everything on my bike is stock as far as I know)

FOG: I thought that ICEs tend to get better mileage at higher throttle openings due to there being lower pumping losses since the throttle plate is causing less of a restriction, assuming you don't lug the engine or rev it way up. The "hypermilers" go full throttle and then coast back down because this is more efficient than having the engine run at a constant power with partial throttle opening. This also accounts for some of a diesel engine's higher fuel economy (another part being the higher compression of a diesel engine).
 

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Your right and I'm aware of that. The problem is it only works to about 3000 RPM. With the EX that wouldn't get you going.
FOG
 

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"Keep the RPM at the torque peak for best fuel economy" is true, but only if you can pull enough gear to have WOT at the speed you want. Tourque peak varies with throttle opening, but dyno charts only account for WOT.

I've also heard that you should keep the engine RPM between the torque peak and HP peak for maximum life, but keeping an engine spinning as high as that range lies for most motorcycles is certainly not the way to keep it living a long time.

Never done it with abike, but when I've checked instantaneus fuel economy in a car, using a scanner, I found that best fuel economy was reached in the highest gear possible at the lowest speed possible, without lugging, that the car could attain in that gear.

In my '96 Impala SS, that speed was around 35 MPH in 4th gear, RPMs were about 1100 and the torque peak for the LT1 comes at 2400 rpm. At close to 2400 RPM, which I could get by shifting into second, fuel economy dropped like a rock.
 

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Simply put, the best fuel economy is obtained by using the fewest revolutions possable regardless of throttle or rpms.

FOG
 
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I'm pulling this out of distant memory so FOG can correct me if I'm wrong. The best "efficiency" of an internal combustion engine is at or near its torque peak. On the dyno I think its called brake specific fuel consumption. At that point you will get the most work/power out of the fuel used. But that has nothing to do with mileage. At our 8500 rpm torque peak you will use much more fuel than at typical cruise of 4500 rpm, because you don't need the full torque output of the engine to cruise. In practice, I average 53 mpg in mixed use 4000-5000 rpm driving, but mileage has gotten as high as 66 mph at steady cruise at 6000 rpm's. Hope this doesn't further confuse the issue......

Rich
 

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FOG said:
Simply put, the best fuel economy is obtained by using the fewest revolutions possable regardless of throttle or rpms.

FOG
That's it I just don't feel like typing it again

FOG
 

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What I want to know is how everybody manages to cruise at 5k rpm or less? ??? Thats really slow, 90% of my highway riding is at 6-7k and I have stock gearing. That's around 70-80 mph indicated.
 

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damarble said:
What I want to know is how everybody manages to cruise at 5k rpm or less? ??? Thats really slow, 90% of my highway riding is at 6-7k and I have stock gearing. That's around 70-80 mph indicated.
I Ride at these speeds and RPM range also , I still manage to get between 45-52 MPG but I'm sure it varies slightly with each bike. IMO if you are staying to the highways & interstates the most , it my be more economical for you to do a re-gear you could possibly see a 2 - 3 MPG increase ?
 

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ok, just for reference, i was turning between 6000 and 6500 continously (so sometimes more, sometimes less) for my 4 hours of riding today. i calculated when filling up and got 51.82MPG. thats running at 70-78mph
 
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