KZ650 - gas mileage

I've used my first tank of gas on my '79, 650 and did the math (92/3.7) and came up with 24.8 MPG for all city driving, stop and go, and me being a new rider. I didn't expect to be in the 50 range, but 25 seems low to me for easy 0-40mph driving. My bike is ALL stock, exhaust, carbs and air box.

Wondering what other 650 members are getting for MPG?

Notes: The bike is running very smooth with good power across the band, mix screw at 1 1/8 turns out, plugs are normal color and dry. I still haven't performed the clean tube test or a carb sync and realize that will change the MPG (about to purchase the Pro Motion tool for the sync). I did a very patient bench sync during the clean and understand it's not a guarantee, but I know it's close based on the sound and feel of the engine at idle and at running rpms.

I keep forgetting receipts or to record info, so haven't done accurate math, but I DO re-set the trip odo, and I can get around 130 miles out of a tank before I am pushing.

I had to flip on the reserve around 85 miles - seems low range. However, being a new rider I'm not always smooth with my shifting around the city and realize that accounts for poor gas mileage.

24.8 is pretty low. Just to make sure: the tank was filled, you rode the bike 92 miles, then added 3.7 gals, filling the tank to the same level? Can you verify the distance traveled?

1981 KZ650-CSR. stock VM24 carburetors. stock airbox & oem-type air-filter. oem 750E exhaust system. stock electronic ignition system w dyna coils. stock sprockets: 13T Fr & 33T Rr.
I do the math at every fillup & typically get 45-52 mpg city-highway.
Around town winding out the rpms = 42 mpg.
Typical highway riding at 55-65 mph = 52 mpg (sometimes 50 mpg, occasionally 55 mpg tops).
Outbound on the freeway against a strong sea breeze headwind at 70-75 mph = 48 mpg.
As a side note, I can go 10 miles after the low fuel warning light starts to glow & 20 miles on RES after the bike starts to sputter from low fuel.

Is 25mpg low? I guess it depends on how heavy the stop and go traffic is. Around here, depending on the day, 25 mpg might be good fuel economy. Here it can take 2.5 hours to go 16 miles on a bad day. One a good day you may be able to do it in 40 minutes. So measuring MPG in traffic here is futile.

A better test would be for you to go for a ride in the country. If possible, travel on scenic roads that have very little traffic and keep the rpms below 4500. Try to stay on roads that have very few stop signs since you may be over revving when starting out. Ride gently and if you don't see at least 35 - 40 mpg or better there may be a problem.

I don't doubt that lots of folks see 50 mpg or better. In 37 years I never have gotten more than the mid to high 40's, and that's if I'm really taking it easy. Typically I get around 40 - 45mpg. When I was younger (even dumber than now) and rode very aggressively it was not unusual for me to get 30-32 mpg, and that was not in traffic.

One question - what do you have the idle set at? Ed

My driving is all stop and go in the city, longest shot about 1 mile, all under 4000 rpms, 4th gear. Idle is set at 1100 and very steady. I don't mind 25 MPG since I really enjoy the bike, but was hoping for more (it's not a Prius).

Wow that is awfull. I get about 40 mpg with mine, 160 miles and I am empty and that is riding very aggresive and with mods to the engine. 720cc piston kit GPz750 cams, pod filters and a 4 into 1 pipe.

I'm not too concerned with the MPG. However I'm interested to get a list of suggestions as to what to look for. Eeks am I really asking for a list here (lol). I rather understand there is a problem that needs to be resolved if there is one.

Maybe something is wrong with your odometer, Its hard to believe I get better gas miileage than a stock 650, I have A 1075, RS34 carbs, Pods & Header & I get 100-120 miles per tankful , 3 1/2 Gal. tank, before reserve
just saying
Pete

LineArtist wrote: I'm not too concerned with the MPG. However I'm interested to get a list of suggestions as to what to look for..

I'd look for gas going somewhere like out the overflow tubes or possibly into the air box and maybe into the engine where it ends up in the crankcase oil.

Take off the oil fill cap and sniff for gas, also watch oil level carefully and see if it is changing.

If the fuel levels are set too high (float adjust) you can have gas running out all the time.

Something is going wrong. I get better fuel economy with my Ford Focus.

LineArtist wrote: My driving is all stop and go in the city, longest shot about 1 mile, all under 4000 rpms, 4th gear. Idle is set at 1100 and very steady. I don't mind 25 MPG since I really enjoy the bike, but was hoping for more (it's not a Prius).

The problem may be simply that becasue of the traffic / speed limit you are always running in lower gears. That will definitely take a toll on the fuel economy. Speaking for myself, when I'm riding in the country and getting 40+ mpg I spend most of the time in 5th gear. Ed