It doesn't make sense but it works!

[baylensman]

So i've read and reread mileage threads here. I usually poke along at around 45MPH on the way to work. the trip is only 2.6 miles one way. Living in town everything is close. I mostly shift early and keep the rev's down. I figured low rev's less gas better MPG.

 

well was I wrong!!

 

on one of the threads someone said "Keep the rev's up" for more mileage, that just seems so counter intuitive to me. More rev's more sparks more ignitions more gas right?

 

So this week, I rode a little harder than usual, not maniacal or anything just stayed in third longer shifted later, kept the rev's up and avoided fifth gears unless i was over 55 MPH

 

Well when the fuel guage hit the refill line i was 30 miles further than usual putting my around the town MPG right at 40 when i usually hit 32-35 mpg.

 

So this week I'm really gonna try and ride differently and see if i can get the MPH up there.

[billmac]

I never use 5th until 70+ unless I shift into it by accident, then I shift right back down.

[Motorcycle Mike]

So this week, I rode a little harder than usual, not maniacal or anything just stayed in third longer shifted later, kept the rev's up and avoided fifth gears unless i was over 55 MPH

 

I NEVER go into 5th gear unless I'm running AT LEAST 60mph. Usualy 65+.

The engine just seems happier.

[CMCOFFEY]

There is a balance to that though. I keep the revs up, and my gas mileage sucks. I have to calm down a bit to get the better gas mileage. I don't mind though. If I wanted good gas mileage, I would have bought a 600cc or less bike. Plus, how many people can say that they have drifted on a touring bike. i've done it twice now.

[cowpuc]

Hi Bay

Yea, pretty incredible aint it... I theorize that one of the reasons behind that madness are the CV carbs our bikes use. Unlike non cv carbs, you are not in total control of the slide movement that is opening and closing the main jet in your carb.. Tiny changes in vacuum that are happening at slower R's while operating in your engines torque curve cause the vacuum operated slide to open and close more inconsistantly and create engine inefficiency.. When you get up into the R's more your getting into the Horsepower curve and into a much steadier vacuum pull and in turn a much steady slide movement making the engine more efficient...

Back in the old days when I was a poor broke young man I couldnt afford a mechanical 4 barrel Holley for my little Chevy eatin 67 289 4 speed Mercury Cougar,, I went to a junk yard (Johnny Minks Junk Yard - had to love Johnny,, if he liked ya everything was a dollar - lotta great stories about that guy) and grabbed a vac operated Holley 4bbl.. Also dug around out there and found this great big ol column mounted Vac Gauge... Guys were always teasing me when I had that Vac gauge mounted in my Cougar,, these were the days of Column mounted Borg Warner Tachs (if ya wanted to be cool),, no body in their right mind mounted an ugly ol vac gauge up there..

Anyway,, I had soooo much fun with that Vac gauge,, it helped me eat lots of Chevy's , allowed me to get consistantly GOOD mileage (24 mpg on a cammed up 289 with L60's) , mainly cause I could tell with the gauge what my carb was doing at a glance..

I have always wanted to leave my tuning gauges hooked on my bike while touring for the same purpose.. I wouldnt be surprised with a little bit of finesse I could close in on 50mpg,, but,,, I know people would laugh at me havin a set of gauges hangin on my bike while touring,,, went thru enough of that from those Chevy guys before I whopped em:rotf:

[baylensman]

love those storeies 'bout the mighty 289. Back in the day guys with the 327/350hp thought they was king SHI@ but along come a guy in a falcon or 65 mustang coupe with a 289 4bbl and a set of headers and would pack their lunch, then eat it, then spit it back out.

[Venturous Randy]

To go along with what Puc is saying about high vacuum, the way you attain higher vacuum is to be more concerned about throttle opening and not RPM's. The best gas mileage I have gotten is where I will downshift rather then lug the bike some and not make the torque pull harder at a lower RPM. Basically, it is more about how much throttle you are using, rather that what RPM you are running. Short shifting is fine if you have the time to accelerate slowly with little throttle.

In my current situation, I am running a V-Max rear on my 83. With riding thru the mountains, I can easily lug the bike a little and it does fine, but if I pay attention, I can get as good of mileage or better than a stock rear. The downside is running at 65mph, I am running close to 4,000rpm's and that can bring the mileage down some. In my last several fill-ups, I have ranged from 44 to 48 mpg's, 2-up.

A good rule of thumb is if you are running along and downshift one gear and without changing the throttle, you increase speed, you are not running at the most efficient throttle and you are lugging the engine some.

RandyA

[cowpuc]

love those storeies 'bout the mighty 289. Back in the day guys with the 327/350hp thought they was king SHI@ but along come a guy in a falcon or 65 mustang coupe with a 289 4bbl and a set of headers and would pack their lunch, then eat it, then spit it back out.

 

Wow Bay,, I thought for sure we would up some of these,, ummm,, older guys like us who would still be ready to about those Ford/Chevy days (notice how I put Ford in the first:rotf:),,, maybe we really did teach em some lifes lessons back then buddie:cool10:

I had an earlier 60's Mercury Comet with a little 3 speed, 260 V-8 in it that ran really good too!! Alot of it that cars advantage was what you were talking about with the Falcs and early Stangs,, Hp/wt ratio was awesome!!

 

To go along with what Puc is saying about high vacuum, the way you attain higher vacuum is to be more concerned about throttle opening and not RPM's. The best gas mileage I have gotten is where I will downshift rather then lug the bike some and not make the torque pull harder at a lower RPM. Basically, it is more about how much throttle you are using, rather that what RPM you are running. Short shifting is fine if you have the time to accelerate slowly with little throttle.

In my current situation, I am running a V-Max rear on my 83. With riding thru the mountains, I can easily lug the bike a little and it does fine, but if I pay attention, I can get as good of mileage or better than a stock rear. The downside is running at 65mph, I am running close to 4,000rpm's and that can bring the mileage down some. In my last several fill-ups, I have ranged from 44 to 48 mpg's, 2-up.

A good rule of thumb is if you are running along and downshift one gear and without changing the throttle, you increase speed, you are not running at the most efficient throttle and you are lugging the engine some.

RandyA

 

 

In my last several fill-ups, I have ranged from 44 to 48 mpg's, 2-up.

 

 

A good rule of thumb is if you are running along and downshift one gear and without changing the throttle, you increase speed, you are not running at the most efficient throttle and you are lugging the engine some.

In all my years of tinkering with this stuff I have NEVER heard that rule Randy:confused24: THAT makes soooooo much sense and soooo well spoken

 

To who ever wrote that other "rule" that says - "ya cant teach an old dog new tricks" I got news for ya:thumbdown:,,,, an old dog just learned a new trick:backinmyday:

THANKS RANDY!!

Puc

[MikeWa]

I have to say the people on this forum are pretty good with their advice. When I first got my bike I heard things like 'better mileage in fourth than fifth' 'keep the revs up' etc. I Pooh poohed all of this because everyone knows you want to keep the revs down for better mileage. That's what overdrive is all about after all. Well they were right. I was wronnnn. Not right

 

So I set about discovering why. Here is what I found. Running at low rpm actually is lugging this engine (whether you feel it or not) and fuel economy suffers. Keeping the engine rpm up in the power band improves responsiveness and fuel economy. So in many cases fourth will provide better economy than fifth. If climbing hills or accelerating a higher rpm helps the engine provide more torque to the whee quickerl. And since you have to crank the throttle less better fuel economy. Is there a limit. Yes of course. Find it and you will get the most out of your bike.

 

Mike

[muaymendez1]

I have noticed that although rpms matter. Riding style matters also. I had a goldwing same year as a buddy of mine abd he always claimed 5mpg more than me. I couldn't figure it out until I rode with him and he kept taking until about 1 minute at a certain speed. In other words from a light I was traveling at 60 in about 20 seconds where he would gradually get to 60 over a minute. Same speed, same distance, sane shifting style at about 3k rpm.he just had a more ginger approach at gaining speed

[XV1100SE]

...So I set about discovering why. Here is what I found. Running at low rpm actually is lugging this engine (whether you feel it or not) and fuel economy suffers. Keeping the engine rpm up in the power band improves responsiveness and fuel economy. So in many cases fourth will provide better economy than fifth. If climbing hills or accelerating a higher rpm helps the engine provide more torque to the whee quickerl. And since you have to crank the throttle less better fuel economy. Is there a limit. Yes of course. Find it and you will get the most out of your bike.

 

Mike

 

Agreed.

 

I find on my 2nd Gen that when I lug the engine there is noticable vibration of the front fairing/windscreen. Usually see this when I shift to 5th too soon or cruising in 5th with no lug and then start going up a hill - then it will lug.

[BlueSky]

I think it has something to do with the efficiency of the engine. The V4 is a high rpm engine and the cams that allow it to rev high have more valve overlap and the more overlap the less efficient the engine is at low rpm. My old 69 SS396 Chevelle with a Crane Fireball cam would burn your eyes with the raw gas coming out the exhaust if you were close to the rear of that car when it idled. Extremely inefficient at idle. I suspect the V4 is most efficient higher up in the rpm ranges and also in order for the bike to go a certain speed, the engine has to produce the same amount of hp no matter what gear you are in.

 

Oh, and I had a 1965 Chevelle with a 300hp 327 that had the 350hp 327 cam and I never saw a 289 that could come even close!! :rotf: Maybe those special solid lifter versions that only had a 90 day factory warranty? I believer they were also rated 289hp. Ahh, the good ole days! We survived!

[cowpuc]

I think it has something to do with the efficiency of the engine. The V4 is a high rpm engine and the cams that allow it to rev high have more valve overlap and the more overlap the less efficient the engine is at low rpm. My old 69 SS396 Chevelle with a Crane Fireball cam would burn your eyes with the raw gas coming out the exhaust if you were close to the rear of that car when it idled. Extremely inefficient at idle. I suspect the V4 is most efficient higher up in the rpm ranges and also in order for the bike to go a certain speed, the engine has to produce the same amount of hp no matter what gear you are in.

 

Oh, and I had a 1965 Chevelle with a 300hp 327 that had the 350hp 327 cam and I never saw a 289 that could come even close!! :rotf: Maybe those special solid lifter versions that only had a 90 day factory warranty? I believer they were also rated 289hp. Ahh, the good ole days! We survived!

Ahh, the good ole days! We survived!! IN BEST TIM ALLEN VOICE "ARG ARG"!!

 

I LOVE your comments here BlueSky,,, sooooooooooooo refreshing!! AGAIN - IN MY BEST TIM ALLEN VOICE "ARG ARG"...

 

I would LOVE to know the cam specs (not just lift/duration but with valve timing specs - overlap) for these V-4's..

 

I wrench back in the 60's at Sunoco in Fruitport,, I used to RUN to the island to beat the attendants ANYTIME I heard a "not happy idling" muscle car pulling in just to smell that unburned 260 coming out of em - OMG I miss that sooooooooooooooo much!!!!!!!!!!! THANK YOU FOR THE MEMS BLUESKY!!!! Those cars were so far beyond my reach financially - I LOVED EM THOUGH!! And I LOVED THAT CHEVELLE of which you speak!!:cool10::cool10::cool10::cool10::cool10::cool10:

 

Man those were special days!!

 

Get my emotions together,,,,, valve overlap,,, yeaaa,, raw gas in fuel at idle,, but BABY,, when ya bring up the R's and the scavenging is a happenin its gearhead party time:dancefool::dancefool::dancefool::dancefool::dancefool::dancefool::dancefool:

 

[Venturous Randy]

Oh, and I had a 1965 Chevelle with a 300hp 327 that had the 350hp 327 cam and I never saw a 289 that could come even close!! :rotf: Maybe those special solid lifter versions that only had a 90 day factory warranty? I believer they were also rated 289hp. Ahh, the good ole days! We survived!

 

That brings back some great memories. My 65 Chevelle had 11.5 TRW dome pistons, 327-350hp cam (L-79), original 68 Z-28 intake(taller than others), Headman headers, 4-speed and a 12 bolt 4:10 posi gear. It was refrigerator white and the interior was white and came out of a 72 Gran Prix. It had chrome reverse wheels and was a beautiful car. I just wish I still had it.

RandyA

[craigatcsi]

I sure wish I could follow you guys!

 

Without a vacuum gauge, tach or throttle position sensor, I simply go by the seat of my pants. BUT, apparently I do a lousy job of it cause I get 30 - 35 mpg, two up, pretty consistently.

 

I am Triking my bike very soon so mileage will be even a bigger issue to me.

 

Craigr

[Money Venture]

I had a 1973 Vega with a 327, Edelbrock Cross Ram intake with Dual Quads, Turbo 400 with Fairbanks Full Manual Shift Kit. It would run along nicely. I too wish I still had that car.

[Venturous Randy]

I had a 1973 Vega with a 327, Edelbrock Cross Ram intake with Dual Quads, Turbo 400 with Fairbanks Full Manual Shift Kit. It would run along nicely. I too wish I still had that car.

 

The engine I had in my 65 Chevelle ultimately ended up in a 72 240Z Datsun that I put 156,000 miles on with a stock 350 with the 327-350hp cam and then with the 327 in it. I did have to go with a different intake as the Z-28 intake was just too tall for the hood. Ironically, this same engine recently went through a complete rebuild and is currently in my son's 65 Chevelle. It is a 300 two door post car and has a 4-speed.

RandyA

[cowpuc]

The engine I had in my 65 Chevelle ultimately ended up in a 72 240Z Datsun that I put 156,000 miles on with a stock 350 with the 327-350hp cam and then with the 327 in it. I did have to go with a different intake as the Z-28 intake was just too tall for the hood. Ironically, this same engine recently went through a complete rebuild and is currently in my son's 65 Chevelle. It is a 300 two door post car and has a 4-speed.

RandyA

 

72 240Z Datsun that I put 156,000 miles on with a stock 350 with the 327-350hp

 

HOKEY SPAMOKEY RANDY!!! Hmmmmmmm,,, maybe that should read,,,,, "I took a couple hundred pounds of tin and wrapped it around 350 horsey's one time just for kicks",,,, crazy,, just plain crazy!!!

I drove my daughters neighbors GENUINE Shelby Cobra last year when we were out in Sac (he also gave me a Cobra Club sticker for my bike!!!) last year,,,,, that had that same "its a motor with a car wrapped around it" feeling that I bet that ZZZ had Randy :cool10::cool10::cool10:

[videoarizona]

Geesh.....youse guys are talking cubic inches! I speak CC's!

 

I drove an Austin Healey Bugeye Sprite for a number of years. My best gas mileage was at 4200rpm...70mph. 42MPG. So the discussion of 4th gear getting better mileage around town makes all sorts of sense...cause the AH had a 948cc engine with two SU mkI carbs...sliders....and holding that slide and jet at one spot gave best economy.

 

Guess I'm going to have to retrain my bod to stay in 4th and take it easy...let the motor hum!

The fuel injected 950 VStar gets shifted into 5th quickly and I get 48mpg on her.

 

david

[baylensman]

Well i'v also noticed not shifting up so quick means not having to down shift so much either. I can come out of a corner cleaner( does that men safer?) not having to quickly down shift. When traffics gets a little dicey being up in the rev's gives a quicker response also. So all around its a better way to be. Just have to think on it a while till it becomes second nature, I found my self shifting to soon on the way home today, had to actually force myself not to upshift in to 5th. Will pay close attention to the MPG next time I fill up.

 

As to the car stuff we need a new thread

[baylensman]

So I;m a week into a new tank of fuel. Been riding different keeping the rev's up!

 

So I show 100.4 miles on the odometer. The onboard gauge shows over 1/2 a tank left!!!! I know its not 100% accurate, but wow! Normally i'd be thinking of getting gas tommorow

[Money Venture]

I filled up Sunday before our ride for the day. I had 171 miles on 3.3 gallons. I know I was careful to get the gas to the same point at each fill up. I know I ride cautiously but this kind of mileage scares me if accurate. Highway speeds 50-55mph. Expressway speeds 60. Careful on the throttle and shifting around 4K. Trying not to lug it. I am close to 100 miles into the next tank so we shall see.

[baylensman]

Well I hit 125 miles and got gas. TOOK 4 GALLSON SO NO REAL IMPROVEMENT. Unless it wasn't full last week, will keep an eye on it.

[SundayRider]

I say twist that throttle and run hard. There is another gas station right down the road.