Gas Mileage Experiment

[naturbar]

my wife wanted to take a ride to Roanoke Va. today, about 130 miles each direction. i decided that since the max speed limit anywhere i drove today would be 65 mph max, that i would make the entire trip in fourth gear. 98% of my riding is two up and my gas mileage lately has been around 33mpg but that was using fifth gear. my max speed today was 70 mph indicated on the speedo and if mine is 7% off then i was actually doing around 65 mph. the terrain from where i live to Roanoke is mildly hilly, so driving @ 65 in fourth kept the rpms in basically the sweet spot and especially pulling the hills. on my refill on the way back home the odo was showing 180 miles and it took 4.3 gals. to top it off - so essentially i got 42 mpg, which is 9 mpg better than i was previously getting. i would like to open up this strategy for discussion, such as pros/cons of fourth gear engine rpms vs. fifth gear engine rpms on longer trips. can anyone with a tach on the rsv or rstd tell me the rpms @ 70 mph indicated in fourth gear vs. rpms @ 70 mph indicated in fifth gear. i understand that fourth gear is technically an overdrive gear but am interested in your opinions. looking forward to the discussion, thanks !

 

buz

[hig4s]

Hmmm, very interesting.. I may have to start avoiding 5th to see if my mileage goes up. Don't have a tach, so I can't help with that.

 

I know I did the that same experiment with my Jeep Wrangler, did a whole tank keeping the revs under 2000, a whole tank at 2500, and a whole tank reving to 3000. Got 15.5 all three tanks. Doh!!

[pegscraper]

More proof that these bikes are geared too high and really need a lower set of gears. Higher gearing and lower engine rpms are not always what they are said to be.

[V7Goose]

I cannot explain your results from this test - too many variables and I wasn't there.

 

But I can tell you that I performed such a test many years ago on my 05 RSV, and the results were very different - MUCH lower fuel mileage for an entire tank of all freeway riding in 4th. Your test might have been flawed; my test might have been flawed; both tests might have been flawed. Who knows.

 

I have done a lot of side-by-side comparisons with other RSV riders, and I am convinced that the ONLY way to get a valid test like this is to do some long distance riding with someone else on the same bike. Compare careful full-up amounts between both bikes for several tanks with normal riding so you know how the two bike/rider combinations compare in efficiency, then have just one of them change something, like never using 5th, and do the same side-by-side comparison for at least one full tank. That is the only way to remove all the other variables such as traffic, wind, road condition, elevation, etc.

Goose

[jfoster]

There was a graph posted under rpm's in the rstd tech section that indicated 70 mph at appr. 3300 rpm's in 5th and 4000 rpm's in 4th, give or take.

Edited May 1, 2011 by jfoster

[Reddog170]

It kinda makes sense. The OP said that he rides 2 up most of the time and is in a hilly area. So If he was using 5th he would be chugging the engine and wasting gas as fourth would put the bike in the power band area of the engine allowing for the needed power for hills and the weight of 2 people (no offense meant) there fore not chugging the engine and wasting fuel. Now if he rode by himself on flats all the time then he could count on the exact opposite results from his test. Shaun

[saddlebum]

It kinda makes sense. The OP said that he rides 2 up most of the time and is in a hilly area. So If he was using 5th he would be chugging the engine and wasting gas as fourth would put the bike in the power band area of the engine allowing for the needed power for hills and the weight of 2 people (no offense meant) there fore not chugging the engine and wasting fuel. Now if he rode by himself on flats all the time then he could count on the exact opposite results from his test. Shaun

I would agree, I have noticed with other vehicles when pulling a heavy trailer on the highway in drive rather than in overdrive on the exact same route fuel millage is up. However when driving the same route without a load using the same vehicle the reverse takes place. I believe this is because in the higher gear, while being loaded down with a trailer the engine must work harder therefore using more fuel.

[jlh3rd]

i have not noticed a 9 mpg difference in gas mileage comparing 5th to 4th, that is really a lot......wish i did....but, i've never had a decrease, it's always about the same.....goose is right, there are a lot of variables, .........you didn't mention winds, this bike seems to really be affected by wind direction as far as gas mileage is concerned......even where you get your gas could also affect you mileage

powerband of engines is a factor.....so 3300 rpm's in 5th, takes more throttle than 4000 rpm's in 4th....but you are turning more rpm's per mile.....so it becomes a balancing act........but a 9mpg difference, i don't know, i think more detailed tests , as goose said, would be needed.....

a few people have the vmax gearing....i wonder what they get....i have considered it

[bongobobny]

Don't know why you got better gas mileage but I do know the Roanoke area is some pretty country!!

[OutKast]

Hey. I live in Roanoke. He didn't stop to see me!

[V7Goose]

Hey. I live in Roanoke. He didn't stop to see me!

That must mean he wasn't really there.

 

Wow, I guess that's proof that these bikes are actually geared correctly! Who woulda thunk it. . . LOL:big-grin-emoticon:

Goose

[saddlebum]

Hey. I live in Roanoke. He didn't stop to see me!

Did you have the coffee on>????

[Condor]

This subject has been tossed around a bit in the past for 1stGen's, and I don't see why it shoudn't hold true for 2ndGen's as well. Staying out of 5th gear at high speeds will improve gas milage unless you have one hell of a tail wind or going downhill. Lower RPM's and wind resistence will eat gas like a horse eating oats.... Case in point. I and several others have experienced 50 mpg when runing in the Sierra twisties. Most of the time in 2nd-3rd-4th gears. Not just once, but all the time. When running on the flats in 5th at 70-75mph I'd adverage 37-38mpg. You'd think it would be the reverse, but it happens every time. On the '99 the first time I took it out on the slab I ran out of gas... didn't know where the resv was but do now....... And it looked like I was getting 25-26 mpg. After tanking up I haven't done any high speed runs, but the mpg is up around 38mpg. So it looks like the same thing holds true. I'll know more shortly as it's getting time for an old man to get out and ride. Also looking at installing a V-Max final. That should help a bunch.

[naturbar]

Thanks to all who responded.

 

V7GOOSE SAID…

I agree, running just one tank of fuel to measure results isn’t going to provide the most accurate data.

 

Thanks for that info jfoster

 

Reddog170 I always up shift on inclines and try to keep the rpms in the appropriate range. Thanks for the input.

 

Jlh3rd there were no significant winds to speak of – kind of a calm & beautiful day. “even where you get your gas could also affect you mileage”….. I buy my gas at gas stations. You are right it being a balancing act – the trade off of higher rpms in 4th gear to possibly give better mileage but also placing more stress on the engine vs. lower rpms to possibly get no as good mileage but reduces stress, etc.

 

bongobobny said…

“Don't know why you got better gas mileage but I do know the Roanoke area is some pretty country!!”. You are correct !!

 

OutKast I wish I had known, we would have enjoyed a meal and a ride with you. maybe next time.

[Flyinfool]

You are right it being a balancing act – the trade off of higher rpms in 4th gear to possibly give better mileage but also placing more stress on the engine vs. lower rpms to possibly get no as good mileage but reduces stress, etc.

 

Running a higher rpm is not necessarily more stress. To low of an rpm beats the bejesus out of the connecting rod bearings.

[flb_78]

Running a higher rpm is not necessarily more stress. To low of an rpm beats the bejesus out of the connecting rod bearings.

 

yup, lugging an engine is hard on the pistons, connecting roads, U-joints.

[jlh3rd]

well, where else would you get gas.....the sign says, "may contain up to 10% ethanol"

the key being "may".so, your mileage can vary depending on the station where you get gas...............i didn't mention stress....

[V7Goose]

I make it a point to buy my gas only from places that sell gas.

[captdrac]

I agree with the type of gas. Was there 10% ethenol or 99.9% gas (not much is 100%). Also, what octgane (84,87,93)? I'm sure interested and will assist in this experiment. I'm being sponsored to be a MSF Coach and have to drive appox. 145 miles round trip to and from the school for 3 days for 2 weekends following Mother's Day. I'll get back with my results before the Memorial Day weekend.

[jlh3rd]

and of course by "gas" i mean the liquified product that results from the "cracking" process of petroleum ( not jelly) obtained from deep beneath the surface of the earth and derived from deposits of plant and animal remains over millions of years.......

.......not the "gas" you get from a can of beans.........

 

....i just wanna be clear......

[etcswjoe]

well, where else would you get gas.....the sign says, "may contain up to 10% ethanol"

the key being "may".so, your mileage can vary depending on the station where you get gas...............i didn't mention stress....

 

 

I have noticed diffrent mileage from diffrent staions and brands. I get the best from Piggly Wiggly and it's non-ethonal go figure.

 

Another problem I have in measureing gas mileage is how do you know you are putting the same amount in each time? It seems like I can fill my bike up to the neck and 10 seconds later it is back below it. If I repeat this process it will finally stop but I don't do that each time.

[Keemez]

Another problem I have in measureing gas mileage is how do you know you are putting the same amount in each time? It seems like I can fill my bike up to the neck and 10 seconds later it is back below it. If I repeat this process it will finally stop but I don't do that each time.

 

This thought has crossed my mind before as well. The only thing I can think to do is add the same amount every time after the autoshutoff point. In the case of a motorbike, say, maybe .25 gallon. Car/truck you can easily get another .5-1-1.5-2 gals in. It must be consistent though.

[Flyinfool]

This is why a one tank test is not a good baseline.

If you do the test over say 10 tanks of fuel (even 2 or 3 is a lot better than 1) then the differences in the fill level will be accounted for.

 

I have noticed a difference in mileage even between brands of gas.

[V7Goose]

I have noticed diffrent mileage from diffrent staions and brands. I get the best from Piggly Wiggly and it's non-ethonal go figure.

 

Another problem I have in measureing gas mileage is how do you know you are putting the same amount in each time? It seems like I can fill my bike up to the neck and 10 seconds later it is back below it. If I repeat this process it will finally stop but I don't do that each time.

Trying to fill the tank to the exact level every time is obviously very important for accurately calculating fuel mileage. And YAMAHAHA has deliberately made it very difficult to fill the tank higher than the bottom of the filler neck. Many of us have vented the neck to facilitate getting more gas in. You can find this discussed in many older threads, including here:

http://www.venturerider.org/forum/showthread.php?t=36392&highlight=punch

And as mentioned in that thread, there is also a tech article on exactly how to do it.

Goose