ran out of gas & gas mileage 1980 750 LTD

So, I ran out of gas this morning on the way to work. I noticed a slight cough, then another...then another. I quick flipped to reserve and limped to the gas station. I got 126 mi off the tank. I believe it's a 2.5 gallon tank, so I got in the neighborhood of 50 mpg. Is this on par with what I should be seeing from this bike? I know my 82 550 LTD got better, but it is also smaller.

50 out of a 750 is pretty damn good really. That's damn near 10 mpg better than I was getting with my kz650 when it was running real nice, and to put it in perspective, I get on average 53 on my brand new ER6n (650 cc parallel twin). If you're running at 50 on a 30+ year old 750 you should be feeling pretty good about yourself!

On my '81 750 LTD The best I have gotten is about 30mpg. I expect to get it better though as I have to sync the carbs and adjust mixture screws still.

Now, I think I have a 2.5 gallon tank... but does that include the reserve portion? My methods were really scientifically accurate... i just filled the tank up to the same point with the wheel turn all the way to the right. Should be ballpark figure accurate though.

Saskatoon - You'll probabaly get better gas mileage too if you put gas in the cylinder, not the air box

This weekend I'm installing a new front wheel bearing and I'm gonna pull the plugs and see how they look. When I first fire it up and take the choke off, it idles at about 1k. Once it's warmed up, it purs at about 1.3k. No hanging idle or anything, so I think I'm not too lean.

You put 2.5 gallons of gas in after riding that number of miles right? Miles/Gallons=MPG, so if you only used 2.5 gallons of fuel for that number of miles you're right at getting 50(ish). I'm not sure about the size of the tank on the 750 LTD, so that's the best answer I can give ya on that one...

It would have to be bigger than 2.5 wouldn't it? To really check you mileage you need to have a pocket note pad, or PDA if you like the gizmo's, and track your fill ups and miles traveled for at least 5 times and then take a calculation. It might be a good idea to check the speedo/ odo for being somewhat close to reality.

Good one, haha.

When I calculate my mileage I always just reset the odo at every fill and see how far I went with how much gas I have to put back in at the next fill. Sounds like what you are doing. It'll get you a close enough number. Motorhead is right that you would want to do it over a long distance/lots of fuel to let things kind of average out.

50mpg? What sprockets are on the bike? It sounds high to me.

Your fuel tank is probably the same size as the one on my 81 KZ650-CSR: 3.3 gals.
The capacity is the total capacity. The reserve isn't a separate reservoir within the tank. It's just a setting on the petcock that allows fuel to flow thru a lower orifice on the petcock.

I guess your fuel level switch doesn't work? They're kinda handy. NOS units come up for sale on ebbaayy from time to time, often times in the $25 range. My low fuel warning light starts to glow when there's about a gallon or less in the tank. I have to switch to reserve when there's about 0.5 gallons. I can go 20 miles on RES.

You're going to replace one wheel bearing? Most folks replace them in sets.

apbling wrote:

So, I ran out of gas this morning on the way to work. I noticed a slight cough, then another...then another. I quick flipped to reserve and limped to the gas station. I got 126 mi off the tank. I believe it's a 2.5 gallon tank, so I got in the neighborhood of 50 mpg. Is this on par with what I should be seeing from this bike? I know my 82 550 LTD got better, but it is also smaller.

1980 KZ750H1 LTD
Tanks size = 12.4 L or 3.3 gallons (US)
Reserve size = 1.8 L or 0.5 gallons (US)
My average mileage is about 37mpg with 45mpg being a personal best and 27mpg being the worst.
From the KZ750 FSM:

If I can get 35 MPG I am quite happy. 50 MPG from a 750 is actually pretty good.

Ok, well when I filled up, I got just a hair over 2.5 gallons and I had 126 mi on the trip. I do reset it every time because my fuel level sensor doesn't work and the damn thing actually leaked, so it has been removed and plugged. If I come across a sensor I will most likly buy it. I have also been burning premium because they have no ethanol added at the gas station I go to.

I believe it's still the stock set up. The PO had upgraded to an o ring chain, and I want to say the rear one is a 32, front I have no clue. It's still the old heavy chain (630 I think). At 55 mph I'm at about 4.5-5k. I drive all county highways to work and don't go over 60 because of cops and the bike just seems to be more comfortable at 55. Plus the ride is 40 miles at a crack, with only 2 stops and limited big hills.

One thing that always puzzled me... if you have a pod or K&N drop in, you increase air flow and you have to rejet to match the fuel. K&N always claims more power and better economy, but wouldn't you offset that by using more fuel? Or maybe it all balances because you need less overall throttle to drive the same regular driving compared to stock setup? (once again, assuming you drive the same route, same speed and same acceleration for both K&N and for stock setup)

Wheeling bearings: I mis-spoke, I am replacing both front bearings right now because one of them was squeeking. The rear has been fine and we are in the process of buying our first house, so the wife has a pretty tight grip on my bike finances

50mpg would be great. Especially when its a US gallon