Need help with Honda Magna MPG

[CoolRob]

Hello all,
I have the Honda Magna 1999 model with Jardine pipes.  I read some review and see that people can get up to 50 mpg on the similar bike.  I can get only 32 mpg.  Any idea why and how I can fix it (if it is a problem).  Thanks in advance.

[hootmon]

Welcome Rob from Safety Harbor, Florida..

Definately some folks on here that can help you with that. I'm not sure about 50 MPH, but better than what you are getting now.. They will chime in...

Great technically knowledgable people on this site..

You can also use the Search feature, there have been many discussions about re-jetting and pipes...

Can you help us all out by modifying your profile and listing your bike (year) and where you are at either near your Avatar or in the bottom of your signature..

Thanx!!!

[dgc67]

Ummm.  Slow down??  Seriously, there are occasions when people CLAIM 50 mpg, but I doubt it is a very regular occurence.  Maybe because they rode 100 miles, doing 45 mph with no stops.  Not to say people exagerate on here...  but I did race a 2008 corvette the other day and held my own.  Not sure if HE KNEW we were racing, but we were!   

[lragan]

Hello all,
I have the Honda Magna 1999 model with Jardine pipes.  I read some review and see that people can get up to 50 mpg on the similar bike.  I can get only 32 mpg.  Any idea why and how I can fix it (if it is a problem).  Thanks in advance.

Hi, CoolRob,

I have a '94 with Cobra pipes.  I reworked the carbs per http://www.magnaownersoftexas.com/tips.htm#A1.31 shortly after I got the bike.

Never had gas mileage as poor at 32 MPG.  When I put in the larger jets to get the mixture right for performance (and quell the deceleration popping problem) my mileage dropped from 53 to 45.  If I ride really hard, or at highway speeds for long distances, it drops as low as 40 mpg.

Does your bike pop when you decelerate, as when you downshift and let the motor drag slow you down?

[CoolRob]

Yes, it does a lot of popping sound when I decelerated.  I have to hold the clutch to stop the popping noise.

[Jerry G Turner]

Sounds like it needs to be rejetted and carbs adjusted, it will cure the popping and increase your gas mileage.

[MarylandMagnav45]

Hello all,
I have the Honda Magna 1999 model with Jardine pipes.  I read some review and see that people can get up to 50 mpg on the similar bike.  I can get only 32 mpg.  Any idea why and how I can fix it (if it is a problem).  Thanks in advance.

Fix that popping in the jets...and after that...to hit the 50mpg barrier...read on.

With a steady hand, slow on acceleration, highest gear (6th on my bike), and max cruising speeds of 70 mph...i can hit 51 mpg going 70 mph on the highway w/ a low wind index.

Like DG said, I can only imagine if I constantly cruised at 50 mph in overdrive like a scooter, I could probably hit the 60 MPG barrier.

I don't know if the difference between the 700 and the 750 makes a difference in terms of mpg...unless your previous owner has done things with the sprockets.

Having a TALL windshield can also make you take a hit on MPG.  The faster you go, the more aerodynamics play a part in your ride.

My bike is also all stock.  I'm sure performance parts can make a person take a hit when it comes to MPG. 




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FINALLY, the best way to get better MPG, is to decrease the weight of your ride/what your magna has to carry.  Unload those saddlebags, decrease carrying things that add more and more weight, AND if you tend to tip the scale...exercise exercise exercise..and you'll see better MPG.

Just think about how Pee Wee Gleason was able to make the v65 Magna a 10 second bike stock.  He only weighed 130lbs!

[dgc67]

Needs rejetting for sure, I don't see how that will improve you gas mileage though.  You need bigger mains and shims on the needles, which actually allows more gas in sooner.  The only REAL way to getter good mpg is to ride slowly and that aint no fun.

Dan,
I don't see how you get that kind of mpg.  I have gotten 40-42 by behaving to the point of it being painful.  I don't run around at WOT or take it redline all the time, but I do like to go.  I would say on average I run it up to 4-5 grand before I shift depending on what final speed I am trying to achieve.  On the freeway I rarely go below 70 and rarely above 90, but I do like to be "faster" than the traffic around me by at least a little bit.  My average on a stock bike, riding almost strictly in commute traffic, mostly freeway, is 35mpg.

[hootmon]

I have  '94 - I average 40-43 commuting most everyday... I have got as high as 50 on a 45-50 mph ride for a full tank... I'm near stock w/ K&N air filter...

[Chad in Michigan]

most everybody i've read about that has poor gas mileage has usually had the dynojet setup already installed. most likely someone has the clips on the wrong setting and/or drilled the slides too much. after running some seafoam or the like in the tank, if you feel up to it take the carbs off and we can help you walk through how to clean them and inspect what's going on.

[Greg Cothern]

Is the rest of the bike stock?  With exception of the Jardine Drag??
The deceration popping is it is too lean on the idle jet, to cure this will be to richen it that wont help your fuel economy but will make it run better and more efficient running. 
Pull a couple plugs and take some PICs of the electrode and post them, my guess is it will show a lean condition as well.  Assuming you ride at highway speeds often then your mains are lean as well, requiring a main jet change to richen it.
We can certainly help you get the jetting closer than it sounds it is now, not sure we can get your MPG up.  MPG has a lot to due with riding style, stock vs mods, winshield vs no shield, speeds, etc etc etc.
IF you want 50mpg you will need to not exceed 3500rpm and clutch/neutral when slowing down to stop as much as humanly possible, and run about 45 mph hehehehehe.

[MarylandMagnav45]

IF you want 50mpg you will need to not exceed 3500rpm and clutch/neutral when slowing down to stop as much as humanly possible, and run about 45 mph hehehehehe.

A good point that I missed in my last post.

this might be a big shocker....I NEVER USE MY BRAKES.  I plan ahead when I see lights, and I just coast to a stop.  I read a physics book awhile ago and it said that its harder to get something to move than it is to keep it moving.  I'm sure Mr. engineer Iragan can provide a more technical explanation.

Most of the times when I'm coasting, the light turns green/traffic picks back up...and I keep moving in my highest gear.

[MarylandMagnav45]

Dan,
I don't see how you get that kind of mpg.  I have gotten 40-42 by behaving to the point of it being painful.  I don't run around at WOT or take it redline all the time, but I do like to go.  I would say on average I run it up to 4-5 grand before I shift depending on what final speed I am trying to achieve.  On the freeway I rarely go below 70 and rarely above 90, but I do like to be "faster" than the traffic around me by at least a little bit.  My average on a stock bike, riding almost strictly in commute traffic, mostly freeway, is 35mpg.

I posted this when I first joined this forum back in August of last year.

""I also have an 85 700cc v45 Honda Magna.

My personal best for mileage was 140 miles before I filled up.

When I was traveling from New York to Maryland, I had a friend with me and we measured the theoretical maximum mileage you can get out of a tank.

I filled up 2.01 gallons going 70 mph at 100 miles (give or take a mile each way).

So I just did the ratio:

2.01 gal / 100 miles = 3.7 gal / x

x = *184 miles for 3.7 gal of gas

*theoretical

Of course, in real life conditions, you are not going to be able to maintain this constant speed 99.9% of the time (not to mention, the conditions: wind/road..etc.. will negatively affect you).

I think I'm safe to say if you fill up to the top, and you don't do jack rabbit starts or excessive speeds, you should probably fill up at around 160 miles to be safe.

I personally like the gas light because since I don't have a speedometer/odometer...I can't track my speed/mileage (can't afford a replacement right now).

P.S. 2.01 gallons at 70 mph at around 100 miles  = 50 mpg ...not bad, not bad at all!""

Anyways, DG, your more technical than I am haha since i'm always asking you for help.

I also will say that I never know my gas mileage when I'm romping on the throttle .

I achieved 50-51 mpg on long flat highways possibly even heading slightly down on a down hill grade because I was going from New York to Maryland...

Thinking about it more clearly now...that's probably why i was able to achieve 51 mpg...b/c like i said just a second ago, going south from Rochester, NY to Baltimore, MD is going from the mountains to the plains basically

[lragan]

You may have a point with the gradient in terrain -- even a gradual one.  Way back when I was in college in Houston, and going to/from Perryton TX in the far northern panhandle (a trip of 735 miles, at least by the odometer on the '55 Studebaker), I always got better mileage going south than going north.  There is about a 3000 foot difference in elevation.  One would think that over 735 miles it could not make a difference, but I consistently used about 8 gals less going from Perryton to Houston than the other way.

I can say that, as a result of others on this forum, I tried running at higher rpm (as opposed to shifting at around 3500 rpm), and the mileage dropped from 45 to 40 mpg.  I was not conscious of a change in average speed, but when the engine sounds like a mad hornet instead of a steady hum, it may inspire higher speeds.   I usually obey the speed limits, and don't speed on purpose, which probably keeps my speed below that of other forum members.  This will positively affect my gas mileage.

To be fair to Greg and others, I like to ride the ranch roads and back roads, where I typically run 40-45 mph average.  This has a lot to do with higher mileage.

[dgc67]

You know, I drive to Central Texas alot and always noticed I got better mileage home but never put two and two together till just now.  Either direction it is hilly, but it makes sense that it is 'more' downhill on the way home.