Topic: Gas Mileage

[scondon]

         

 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.

    When you set the points gap and did your timing did you check and set the advance timing? Also, how is your air filter?  Good timing and air flow are the first things I check if my mileage starts to drop. If you are satisfied that your plugs are firing on "F" at idle and between the "1[]4" and "2[]3" marks at 2200rpm and above, then you might try removing your air filter and see if performance and mileage improves. Fill up the tank, ride for 20-30 miles, and see how much gas it takes to refill and calculate your mileage, any improvement?

     Your set-up doesn't sound like it would need any radical carb tuning. I would first recheck that valve lash, timing, and idle air screws(carbs) are all set to spec and that you are getting a healthy spark at the plugs.Satisfied? Then check airflow.

[Kevin D]

I get about 175 miles to reserve. I try to stay off of reserve as I have a very little rust in the tank. I clean a tiny bit of crud out of the

petcock bowl once a year and less out of the float bowls. Mileage is about 45-50 mpg on country cruising. I have yet to put $10 in a

fillup.

[eldar]

I got about a 6 gallon tank total. I go about 200 - 220 before flipping to reserve.

[8 Track]

She (cb750k6) starts cutting out at 100 miles if I make a lot of right hand turns and about 120 miles if I'm turning left more.     That was last year, before I drilled my emulsion tubes and replaced my wallowed out main jets.  One of those 1973 ish road tests on the main sohc page mention mileage and if memory serves me right, it's around 130 to reserve. 

[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.

    When you set the points gap and did your timing did you check and set the advance timing? Also, how is your air filter?  Good timing and air flow are the first things I check if my mileage starts to drop. If you are satisfied that your plugs are firing on "F" at idle and between the "1[]4" and "2[]3" marks at 2200rpm and above, then you might try removing your air filter and see if performance and mileage improves. Fill up the tank, ride for 20-30 miles, and see how much gas it takes to refill and calculate your mileage, any improvement?

     Your set-up doesn't sound like it would need any radical carb tuning. I would first recheck that valve lash, timing, and idle air screws(carbs) are all set to spec and that you are getting a healthy spark at the plugs.Satisfied? Then check airflow.

Thanks for the replies........I guess I'll start filling it back up around the 100 mile mark.

scondon.....I have yet to adjust the valves and timing. I plan to do that this weekend. After I got the bike running, it ran so well with new points and plugs I figured I would put some miles on it to see what else I was in for.

Hopefully my aluminum rims will be here tomorrow, then its off to the shop for new tires, sprockets and chain.

[WiredForStereo]

I've only gone one whole tank since I got my Cb650, but it got 46 mpg and hit reserve at 120 miles.  I am sure it will get better though since I've cleaned my carbs and stuff.

[ScarThumbs]

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

I get about 170km on my '78 550k, without turning on reserve.  Did you count your reserve?

That's about 110 miles, or 45 mpg or so. I was hoping for better when I got the bike.  That's mostly city, conservative driving, too.

Would a recent model get the same mileage?

[Cowboy48]

I get close to 45mpg on my stock 750 K5

[kpier883]

My '74 750 always goes to reserver just before or occasionally just after 100 miles.  I get 29 - 32 mpg.  I plan on putting in leaner jets though and hope to improve significantly.

[GroovieGhoulie]

I can go around 100-120 or so, depending on how aggressive I ride.  I usually get into the 50s for mileage, which only dips into the mid-40s even when I cuff it hard.  I haven't experienced it, but the low '60s might be possible with short-shifting and easy use of the throttle.

I love the 400! 

[8 Track]

She (cb750k6) starts cutting out at 100 miles if I make a lot of right hand turns and about 120 miles if I'm turning left more.     That was last year, before I drilled my emulsion tubes and replaced my wallowed out main jets.  One of those 1973 ish road tests on the main sohc page mention mileage and if memory serves me right, it's around 130 to reserve. 

Update: I replaced my needles and guides, which completes my carb rebuild and I consistantly hit 125 miles before reserve, sometimes as high as 140.  Plugs are perfect, pipe isn't all carboned up and the bike just plain runs perfect.

[scout18]

I figured about 45 miles on the F1 but it is not a a supersport engine. It is running the k carbs  with f1 4 into 1 and pods with 105 mains. Funny thing is that it runs great, idles fine, but just easing along between 2-3000 RPMS it makes popping noises out the pipe. Not sure what it is but as long as I'm above 4000 rpm there is no popping and the plugs look good

[schmidbc]

I'm currently running a dyna S ignition and dyna coils, iridium NGK spark plugs, stock carbs and airbox.  I'm hitting the reserve around 83 miles.  According to my math, that's 21.9 mpg.  Bad mileage, good performance.

If anyone has suggestions on how to scale that back, I'd be very interested considering my new Civic is getting aroung 35mpg on average.

[amattel]

my 750k2 has wiseco 836 kit, cv carbs from a cb650sc, pod filters,  and 4-1 jardine pipes...  I usually get 40-45 mpg and hit reserve around 120-130 .. the most miles I have put between fillups is 159.  I believe the tank is 4.3 gallons including reserve..

Adam

[cadler]

My K1 had to hit the reserve at 130miles, at about 33mpg. I am still breaking it in.

[Bob Wessner]

Anyone have a sense for how much fuel is in the reserve portion of a 750 tank? I realize it varies somewhat as I believe the tanks themselves and their total capacity varies a bit between models/years. I've never actually hit reserve, but a couple of weeks ago I thought I would try to find it on my K0 with a K2 tank. I got to 150 miles, still no reserve, though I have to believe I was with a teaspoon or so  of getting there. I average 45 mpg and don't do too much city driving. I check it occasionally more to determine any changes in performance that might suggest a tune-up, etc.

[78_SaltLick]

i have a 550 4 into 1 exaust, i get about 45 miles per gallon, ive hit reserve a few times....ive never had a lag in time before it kicks in. Sometimes i can reach around and flip it to reserve while its cutting out and it will just pick back up without me having to even pull over....

[ProTeal55]

I never get the chance to hit "reserve" , as I am anal about having fuel in my vechiles, plus their is a
gas station at the end of my block..

Call me obsessive compulsive 

[Bob Wessner]

Call me obsessive compulsive   

OK, you're obsessive complusive. 

[ProTeal55]

Call me obsessive compulsive

OK, you're obsessive compulsive.

Thanks.
1st step in recovery is admittance...

[VitaminCB550]

Funny story, even if a little off topic... after a couple of beers (and some tequila ) one night, my buddy pulled all the plug wires off of my 75 550k. Didn't find out until next morning: Checked gas (about 1/3 tank), started bike... ran rough, though I know that my carbs take a little time to get cleaned out sometimes (1 will go, then 2, 3, 4, its wild!) so I rode it down the road. It's sputtering bad then it just dies . Look in the gas tank - > NOTHING ! Every one of the plugs were arcing , forcing me to use almost full throttle, thus draining the entire tank. It's amazing what these bikes can do !

P.S. This board is the reason I still have my bike. After being around an endless supply of sportbikes and actually RIDING a hyabusa, you guys make me really appreciate what I have. Thanks! 

[amattel]

I use the reserve feature all the time.  When it starts to run "funny" and the trip odometer is about right, I reach down and flip it to reserve and everything is cool again after a few seconds.  at that point I have  about 40 miles to find gas.

I always notice it running wierd when the float bowls start to get low in plenty of time to flip it.

Though somtimes I have actually started a trip without remembering to turn the petcock on and 1/2 miles down the road I get all confused as to why its running so bad

If I know I will be in a situation where I do not want to deal with flipping it after it affects the bikes performance, such as heavy traffic, then I flip it early and go find some gas.

I finally got the gas cap seal replaced so I can fill it to the brim without it sloshing out which gives me better range.


Adam

[ProTeal55]

Though somtimes I have actually started a trip without remembering to turn the petcock on and 1/2 miles down the road I get all confused as to why its running so bad

One of my favorite things to do while working at the V-Twin shop was to watch "hardcore bikers" start their bike and rip down the street, only to realize that their gas wasn't turned on 
Watching that never gets old....

[dusterdude]

joe,you`re such a mean ass.

[8 Track]

Bob, 1.3 miles in the reserve portion, 4.5 total.  That's out of my 1972 chiltons.