poor gas mileage

[sig310]

Bought a '98 1200S a month ago.  It looks like I'm getting about 30/mpg.  Seems problematic.

Prev-owner did say a) it needs a tune-up and b) every 1500 miles he needed to clean the fuel lines (or something).  He took good care of the bike, generally speaking. Thoughts?  Thanks.

[PeteSC]

Does the bike have a jet kit and aftermarket exhaust installed?
  That's gonna have a big difference in our answers.

  If it's stock, a '98 1200 should be able to get into the low 40's at cruising speeds.
  Usually a jet kit and exhaust drops this a bit.  

  If it's stock, the normal stuff to check are  plugs, air filter, carb synch....than you get into more technical 'carb' stuff that's beyond me..

  Does the bike seem to run OK?


  I'm not sure what fuel lines he's talking about cleaning.  There shouldn't be any 'lines' that need to be cleaned every 1500 miles, unless he's only riding 1500 miles a year, the bike's sitting, and the fuel is going bad....gunking up the carbs and fuel system.
  What kind of miles does the bike have on it?

[Daytona]

Bought a '98 1200S a month ago.  It looks like I'm getting about 30/mpg.  Seems problematic.

Prev-owner did say a) it needs a tune-up and b) every 1500 miles he needed to clean the fuel lines (or something).  He took good care of the bike, generally speaking. Thoughts?  Thanks.

              Hey like Pete SC said! But one big factor i found is many times the primary's are screwed with and screwed out to far!! If they got to be out more than 2 1/2 turns its way too rich at idle or low rpms. Tail pipe should be a dark grey! not black! I was told to turn em out, MPG dropped to under 40. Set up the idle with the adjuster to about 1200rpm, adjust primary's in until it cuts out that cyl, out til smoothest idle for that cyl. Do all 4 mine wound up being @ #1&4 is @ 2 1/2 turns out #2&3 is @ just under 2 1/2. Fuel mpg back to 45 hwy   Works for me!! Maybe the air box water etc drain hose by exhaust collector is what 1st owner was cleaning.

[Dragbike]

Well I guess I have been very lucky, I have only had my 2001 1200s for a short time. But I am getting 47.826 MPG (Highway)! All that I know so far is that it has a Yosh RS1 and the mixture screws have been drilled out. I will know more in a few weeks, as I ordered a jet kit for it. It has 10,000 miles on it and I saved it from the front yard of the owner (Chain Rust!) and I think the EPA, FBI, CIA,GOV Approved CAPS/PLUGS were not removed by a Pro. As per the scrapes on the frame and the top of the Alt. housing on the engine block from a pray bar used to either remove and/or reinstall the Carbs. Updates to come later.
Thanx
Brent  
(PS Yah,Yah,Yah, I know, I said I was not going to "HOP" up the Bandit since I have 2 Drag bikes..........I think I am hooked on power and Speed... ER AH.. The ability to remove my self out of a dangerous situation with the ability to accelerate out of Harms Way...That’s my Story and I sticking with it)  

[2005B12S]

Thats like buying a Ferrari or Porsche and complaining about insurance/mileage.

You purchased a 1200cc motorcycle weighing 500 lbs, fuel economy isn't going to be great.

For maximum economy I recommend a 450cc twin.

[ptitza]

Thats like buying a Ferrari or Porsche and complaining about insurance/mileage.

You purchased a 1200cc motorcycle weighing 500 lbs, fuel economy isn't going to be great.

For maximum economy I recommend a 450cc twin.

But don`t you want to get possible fuel economy from what you got?
Besides that, poor fuel economy might indicate other problems, like poor jetting,etc.

[rider123]

You could try the mixture screws if they're drilled out. For example I've been fooling around with my mixture screws these last couple of days to further fix the screwed up jetting from the factory.

For example on my 2005 Bandit 1200 with stock everything:

temp 9 degrees celcius, nice sunny day.


Haynes manual standard turns out 3.0

At 3.0 it works but is horribly rich, I can smell it when idlling at a stop light and not fully warm. Fully warm it idles ok and not so much smell, but very mushy down low (too rich)

2 1/2 turns out I'm getting it to idle ok but definately too lean, not too mushy down low but a bit and a little surging at cruise rpm and slight hesitation.

2 1/2 and 1/8th out is perfect but when it gets super cold and clear it gets slightly lean again.

I have it now at 2.75 turns out and it idles fine and not mushy at all. However it's still cold so when it gets warm out I'm probably going to have to lean it out slightly in summer temps >15 degrees celcius. Probably back to 2.5 and 1/8th turn out or so. I may just turn in the screws and extra tiny touch to see if it gets even a little better for fun. But remember its winter so when hot humid air comes along it may be a tad rich.

Also, Octane for me helped alot too. I was running 87 Octane and down low with larger throttle inputs, when fully hot, I was getting some pre-ignition and idle was rougher. I had a half tank of 87 octane and filled the rest up with premium at 91 octane and there was a huge improvement. The effective octane rating is around 89 or so. I know that mixing grades is not good so I will fill up next time with premium and then try 89 octane to see if it's ok. 87 on my bike is too low. Fuel milage rose dramatically and I got a bit more "snappyness" as well when increasing octane levels.

This may have something to do with the TPS sensor that advances the timing based on throttle inputs. When I got my bike it was set from the factory "lazy", meaning it wasn't giving much advance at open throttle inputs. When I set it correctly according to the Haynes manual it really helped alot with the throttle response so it must be advancing the timing correctly now. However as you advance the timing you are going to need slightly higher octane or you will get pre-ignition like on my bike. I don't think this effects the older (<2000) B12's as they dont have a TPS. It also explains why the newer Bandit's get slightly better milage as the combustion will be slightly cleaner and more complete when the timing is slightly advanced on open throttle positions.

[Daytona]

Fuel x miles going down the tubes! Down to about 35 per was over 40.. Almost 40k on the trusty stead. Plugs (champion) walmart cheapies been in there for over 15k, chain x ring DID about 19k air filter is a UNI foam type that has been in there for a while. But the zukster is running great!!! Maybe the big jacket i am wearing now too and from work? The windier winter weather here in FL? or THE DRIER AIR? Anyone got any one thing they just happen to find made a diff when it was running ok? I went to a RS3 street can from a race core?  Red01 said it maybe i have it out of the sweet spot! My 16t X 43t rear maybe to tall! 4k rpm=79mph.. What is the sweet spot ratio if I95 is where i spend the most time? My job commute just got 18 miles longer ea way so 20 of 38 of it will be superslab. Maybe i need to un twist the throttle thing a bit! There isn't much diff between cold @ 70mph or 105mph! But makes a big diff to the amount of time your in it!!      

[rider123]

You could also try cleaning the air cleaner, maybe it's dirty and not giving you max effeciency. I think one guy here cleaned his air filter after a year or two of not cleaning it and gained 5 or 6 mpg and got more power. It's something thats easy to try and free.

Also driving in the city really seems to hurt my gas milage. Are you driving mostly in the city? I get probably only around 35 mpg in the city with lots of stop and go and idleing for a while waiting for traffic, time on choke warming up, etc. I haven't seen what it can do on a long haul though as it's still winter and my bike is not yet broken in or tuned to %100. I'm getting there but it's probably tuned to around 95% I'll be able to tune the last little bit when spring comes and can go for long rides. In the winter you're going to get worse milage due to the usage of choke and whatnot. Me being in a major city it's practically all stop and go traffic, also I have to go on afterburners alot to get around all the winners in their cars that shouldn't even be on the road!

As an added point, I tend to disagree that if you if you have your mixture screws turned out more than 2 1/2 it's too much, at least on this bike. Every bike is different. If I turn my idle mixture screws to 2 1/2 it so lean I get a little backfiring just giving it a little gas. Some people on this board have them turned to 3.5 turns out just to kill an off idle stumble. Mine are currently 1/8th of a turn under 3.0 and it's pretty good but there is a slight flat spot just off idle, however it's still cold so when it warms up it will probably be perfect. Haynes manual states that the standard is 3.0 turns out. So I'm LEANER what the "official" factory settings are.

However we may be artificially richening up the screws to make up for the small mains. I hear that putting one shim under the needles generally smooths out the low rpm throttle response and cleans up the mid range. If I addes a shim I may very well get away with 2.75 turns out. This is all on a stock bike of coarse. In hot, humid Florida where Daytona lives his bike may be perfectly fine at 2 1/2 turns out but for us outside a tropical jungle we're going to need a little extra juice. I'm in the middle of winter and I only need less than half a turn extra than tropical florida. It's not that much. I may be too rich for summer, I'll wait and see but it's close. If in summer I may have to put it to 2.75 turns out to be perfect it's only 1/4 turn more than tropical florida.

[Daytona]

Ok Done some playin around with the air box! I put the snorkel back in the stock hole! Come to find out that aids in the engine getting air at say above 75 mph!! The air filter isn't bad enough to take the tank off (or lift up) to clean the thing!! So i opening up about 6 of 12 of my 3/16" holes i drilled in the cover. (My version of the airbox mod) When i drilled the holes and with new UNI filter the bike wouldn't run worth a darn, shimmed and moved clips but didn't like the radical results, went back to old settings, Duct taped holes. Now with a bit of dirt, 6 holes open, it seems to run better especially @ 100+. The dirtier the filter the better it works! The filter never gets a build up except rite in line of the snorkel/hole anyway. Last tank was 38 mpg? maybe making less fast starts so i could post my + results! The snorkel makes no neg diff that i can tell! seems to help @ hi speed. It did & does run great! Smooth, fast, Idles great! Got some info on the ratio that works best! Its what ever works for you! 3.00 is best all around, up for you rocket launchin wheelie riders, down for us comuters! 2.86 is a bit tall! I think if @80mph the bike gains say 5 mph if you get in a tuck, it should be ok, more and your over geared?          

[rider123]

Well it may just mean you were slightly lean Daytona. I think the snorkel is a low tech velocity stack and would slighty close off some air making your mixture a tad richer which would help at midrange and top where it needs the most fuel. Glad it's working out for you. I like the idea of you drilling a bunch of small holes so you can add and take away air as nessesary. Do you have the stock jets and pipe still on there?

Also if you've shimmed your needles your going to use a little more fuel than stock. Most people get around 42-45 MPG so dropping to 38 is not that bad at all.

[terrebandit]

Hey man,

I've got a 2000 model with a HS stage 1 jet kit and HS comp pipe.  My average mileage in the winter is about 34 mpg.  I have never gotten better than 39 mpg and its been as low as 30 mpg.  

2G's get much better mileage than 1G's.  Really, thats the only thing that bothers me about my bandit.  However, mine runs awesome and pulls great when I need it.

Dave

[Banned it.]

Just had the emulsion tubes replaced on my 98 B12. The holes in the tubes were completely oval, mileage had dropped from 46 mpg to 37 mpg, but remember our gallons in Oz are bigger than your gallons. Bike shop said the tubes wear after about 40000 km. Makes engine run rich down low resulting in small drop in power and torque and big fuel bills. Engine now picks up more cleanly and power increase is noticeable. Top end was still ok with worn tubes.