Topic: Gas Mileage

[Bob Wessner]

Fifty mpg on my K0, but it rarely sees the far side of 4K rpm. Most riding is on rural roads vs. interstate, in other words not very agressive.. getting too old for it. 

[Dave Wyatt]

I get 30-31 most of the time on my Hondamatic, once in a while as much as 33.  That two speed tranny and torque converter just don't help, but it's still better than the 15 my pick-up gets.

[lordmartin]

I did a cross country trip east to west and back on my '74 750 (in fact 20,thousand miles all over the us!) and kept a log of my gas mileage. It averaged about 45 miles per gal and it runs a bit rich so I prob could have got more. I did have higher gearing than stock tho'. Two teeth down on the rear which made for better touring. My bike never missed a beat as usual even loaded up with a ton of camping gear.
I am now returning to the UK so my faithful bike is for sale in the classified section.

[KCs76Cafe]

Just wondering how many miles you guys are getting before having to use the reserve on your 750s. I think I pulled a FUBAR today 

Was gonna ride the bike up to my father inlaws for him to do a look/see about covering my seat. Got about 10 miles from the house and the bike started cutting out. I figured something was up and maybe fouled a plug so I turned around and headed back towards the house.......but didnt make it. I opened up the tank to make sure I had gas......looked like about half a tank. I even flipped the petcock over to reserve and it wouldnt fire.

After calling my stepdad to come get me in his truck........luckily I had just made an aluminum ramp at work last week...... I tried it again and it still wouldnt fire(still on reserve) So Im back at the house, the bike is unloaded, my stepdad is gone(luckily again)  I hit the starter button one more time before changing the plugs and the bike fires right up  Would it take that long for the gas to get to the carbs after switching to reserve?

I've only put about 130 miles on the full tank of gas after getting it ready to ride. I figured I would have got better mileage than that....or is this average? The pipe is a little black like its running rich and I dont know what has been done to the carbs by the POs. It runs and idles smooth with no hesitation so I wasnt gonna fool with them.

[WHALEMAN]

Should not look like half a tank left when it needs to go on reserve. NO, it should not take more than 5 seconds for fuel to flow after switching to reserve.
first:
1. Pull the petcock bowl and pull out the screen and check.
2. Pull the two small screws on each side of the petcock handle and check if something is lodged in the circular rubber gasket. You will need to drain the tank for this step.
3. If both these check out OK then pull the gas lines to the carbs off the petcock and put a small cup under the two outlets and turn the petcock to both run and reserve.( put the gas back in) You should get good flow on both.

Hopefully you do not need to pull the petcock off as the two screws can be very hard if they have never been removed. DAN

[bill440cars]

KC,
    Sorry to change the subject but, I couldn't find your post on the mini fairing, what did you decide or have you decided yet to use the mini fairing or not? I was just wandering. Later on, Bill

[KCs76Cafe]

Im gonna take it off. I like the looks of it while sitting on the bike......ie. drivers view ... but looking at it from the front just doesnt appeal to me. I might try and sneek it in to my paint guy at work and get him to paint the lower section green to see if that helps. I'll probally just go nekked. I like the pit bull look.

So.......does nobody know what kind of mileage they get? I figured mine at 28mpg.......is that normal or low? Or was this a dumb question? 

[miller_87]

Well on my cb500 4 cylinder running stock carb setups w/ 4-2 turnouts and no baffles, I was only getting 33 mpg, but put a 4-1 MAC exhaust on recently trying to solve that problem along with a quieter exhaust...we'll see what happens after the rejet.

[scondon]

          If your running rich and flood the cylinders it can take a long time for them to "air out" and be able to fire again. Sounds like this could be what happened to you.Weak, intermittent spark caused by failing condensor, bad points,bad plugs or bad plug cap will often show up after the engine gets HOT and should be considered if a full maintenance tune-up doesn't cure your mileage woes. There are a number of things to consider BEFORE doing any carb tuning.

   28mpg sounds a little low, but i've gotten worse by driving like a maniac from stoplight to stoplight. Best was 42mpg, worst was 26mpg. Set 35mpg as a goal.

 Are you running a aftermarket exhaust? Pod filters? Dyna ignition? Or any other performance bits? Or is the bike ALL stock except the seat?  Knowing any of this would help, as well as what work you've done so far to "get it ready to ride". Be happy to help, that bike looks sweet and belongs on the road

[quietlikeachurch]

So far the best average I've gotten on my 750F is 40 miles per gallon, and that was during a looong trip down a 55 mph road (and I even hit the ton at one point).  Around (down)town I get miserable gas mileage and my plugs foul after only about 200 miles.  Of course, the town I live in is Richmond, VA where there is a 4-way stop at pretty much every intersection.  I don't think any SOHC/4s like standing still.

-Ian

P.S.-  Get rid of that fairing...just plant your face in the gauges at high speed.  You'll look like a fool but you won't feel any wind-whipping; and most importantly, you won't be a sissy!

[Bob Wessner]

I don't do much stop-and-go around town riding and it only takes about 5-10 min. tops to get out of town onto rural roads. I rarely see the far side of 65-70 mph so most of the riding is in the 55-60 mph and I average 45 m.p.g. on my 750.

[Steve F]

I usually start looking for a gas station at the 100 mile mark.  I'm not even close to using the reserve at that point, but reserve is needed at about 130 miles or so on my 750F

[KCs76Cafe]

         

 Are you running a aftermarket exhaust? Pod filters? Dyna ignition? Or any other performance bits? Or is the bike ALL stock except the seat?  Knowing any of this would help, as well as what work you've done so far to "get it ready to ride". Be happy to help, that bike looks sweet and belongs on the road

Kerker 4-1 exhaust,stock airbox, points are new and the plugs were a week old.

[GeoffT]

My 550 gets to about 100 +  before hitting reserve. I,m guessing that is about right for a 550. Understand it is a 3 gallon tank with less than a gallon on reserve.

[cben750f0]

best i ever got out of the F1 was 180km.... but that was b4 i put the pods on and messed with the jetting.... never found out how far i could get with reserve.... aint no way i hell i am pushin 230 odd KG's of bike anywhere ...peace

[Japbikemike]

'78 CB750F---43mpg, lots of highway, high speed nonsense.  175 miles per tank (stock), no reserve.

[jdpas29]

my K8 gets 45 mpg

[KB02]

          If your running rich and flood the cylinders it can take a long time for them to "air out" and be able to fire again. Sounds like this could be what happened to you.Weak, intermittent spark caused by failing condensor, bad points,bad plugs or bad plug cap will often show up after the engine gets HOT and should be considered if a full maintenance tune-up doesn't cure your mileage woes. There are a number of things to consider BEFORE doing any carb tuning.

I had this happen on my Ducati, once. My DUC runs a litte rich due to the set up on it and it tends to shorten the plug life. As it was explained to me: The harder the condencer has to work to make the spark, the shorter its life will be too. It ran fine when cold, but as soon as it got warmed up it would start to fail. Felt just like I had lost a coil. Now I just change plugs whenever I change the oil. Probably not nessasary, but they're cheap, and it beets trailering the bike to the shop and waiting for parts to come in for it. (That summer sucked! I lost three months of riding over it)

And definately check the fuel flow. My Dad and I once destroyed an old snowmobile engine (Lets try this, lets try that, lets bore it out... ect...) before we finally found a peice of lint in the fuel line in the tank. It would work fine for a while and then clog up the line, then settle back down, the clog up the line...

[GeoffT]

'78 CB750F---43mpg, lots of highway, high speed nonsense.  175 miles per tank (stock), no reserve.

What size tank does the 750 have?

[lassenc]

best i ever got out of the F1 was 180km.... but that was b4 i put the pods on and messed with the jetting.... never found out how far i could get with reserve.... aint no way i hell i am pushin 230 odd KG's of bike anywhere ...peace

I can get up to 220km, in that area, on my 550K

[dusterdude]

49 mpg highway

[soeltjen]

37 mpg.  At 130 miles I start looking for the gas station.

[Jonesy]

I get around 180 miles before I need reserve. (Stock 750 K3)

[DrMark]

1978 CB550K....averages around 47-49 MPG. Mostly riding country roads. I've done over 150 miles before changing to the reserve.

[Japbikemike]

'78 CB750F---43mpg, lots of highway, high speed nonsense.  175 miles per tank (stock), no reserve.

What size tank does the 750 have?

The book and reference materials say 5 gallons.  But, the most I've ever been able to get in it is a solid 4 gallons (US measure).