Tank size on 1981 GS750L same as 1979?

[Detman101]

How can this be true??
And if it is true what is my tank's problem?

1979 GS750L
Fuel tank capacity: 18 l (4.8 gal.)
Reserve: 2 lt. (0.5 gal.)

That means that the main tank is 4.3 gallons with the reserve being 0.5.

Why is it that I run out of my main tank after only 2.26 gallons? Assuming that there is the same tank on the 1979 version and my 1981 version I should be getting more mileage per main tank right?
When I get to about 90 miles (used 2.26 gallons of fuel) the bike starts to die down unless I switch it to reserve.

Does anyoen know what can be causing this? Could the filter inside the tank that attaches to the petcock be clogged up? If so, can I take it off since I have an inline filter on the bike's fuel line?
Could it be a vacuum problem with the gas cap?
I'm getting a little confused as to why I keep having to fill the bike up after it's only used 2& 1/4 gallons of gas.

Advice?
Thanks in advance.
Dm of mD

[chuckycheese]

Different

I think the tanks on the 1979 model is completely different than yours...(it does look the same but I think it's different). I think your tank is just like mine...if so, it holds 4.0 gallons. (The GS750 LN's hold 3.4, the LT and LX holds 4.0, the TZ holds 4.2, the ET, EX, and EZ holds 5.0 and all the others hold 4.8.) :roll:

As far as why you'd go on reserve with so much gas left in the tank.....if you've got a Pingel petcock, that's the answer. They have a very tall stand pipe (unless you shortened it like I did) and go on reserve with lots of gas left below the reserve line. I can go about 155 miles before I hit reserve...I figure I've got about 15 to 25 miles to find a gas station.

[frosty5011]

Detman,

You don't have an 18 liter tank, you have a 12 or 13 liter tank (maybe even a little bigger, depending on the year, I don't have that data). You've got the "L" model, not "standard" GS750. The standard is the one with the 18 liter tank.

[mdole]

I have an 81 GS750L and I believe my tank is 4 gallon. It must have close to a gallon in reserve as it usually takes less than three galleons to fill up unless I have run for a ways on reserve and then it takes a little over three.

Mike

[Detman101]

I'm definitely going to have to switch tanks. I'm not a person that likes filling up every 60-90 miles and I sure as hell don't ride on reserve when there are gas stations right near me. I even carry a can of gas when travelling as insurance.
Filling up everytime the tank uses 2.26 gallons is getting downright annoying! :x

What kind of gas mileage does everyoen with the stage-3 kit get?
Also, Am I doing the calculation for gas mileage right?
I get 90 miles on the highway and about 50-60 miles in town per 2.26 gallons. At this rate I'm filling up every other day at a cost of $4.00 turning into 16 dollars a week. While not TOO bad it's right up there with my car. (Pontiac sunbird 17-31MPG/ 11GAL tank).


Dm of mD

[chuckycheese]

Reserve

I agree with you about the reserve "thing".....to me, if you go on reserve with more than about 25 miles left in the tank, it's a worthless feature. :?

However, I think you'll find it's a whole lot easier to change the petcock than to change the tank. :roll:

[Detman101]

Well, I was thinking that some larger...better designed tank from maybe a sportbike could be fitted to the bike. Something that sits more ON the frame instead of wrappping around it and cutting the available fuel in half.
I really do get the feeling that the only fuel that I get to run off of is what is in the side that the petcock sits in.
If I go to a pingle petcock will that increase how far I can go before filling up again? I really don't want such a stupidly large reserve. Anyone who doesn't have the smarts to head to a gas station as soon as your main tank runs out deserves to push their 500+ lb beast to the next station. I, however, am not one of those idiots.
I monitor my mileage very closely and usually know when my bike's main is about to run out. I know my Vulcan 750 better than it knows itself when it comes to predicting the way of it's tank!
Perhaps I could fit it's tank on the GS?

Well, does anyone have any suggestions before I really turn this into franken-bike? Stopping so often is so annoying...


Dm of mD

[chuckycheese]

Tank

I think trying to re-fit a different tank would be a nightmare. If you do a search of my posts you'll see a number of messages that I wrote when I switched mine over to a Pingel...it's a really tight fit but it will work just great.

As you will see from the posts, you can adjust your reserve capacity by shortening the standpipe. Actually, you'll have to do that anyway because of the height of the gastank in the area where the petcock is located. As you'll see from my earlier post, here, I figure I've got about about 15 to 25 miles left in the tank when I have to switch over to reserve. In order to achieve that, I shortened the standpipe by about 7/8 of an inch (as I recall) with a tube cutter.....really very simple.

If you decide to do it and you're unclear about any aspect of the "operation", let me know and I'll be happy to help!

[Detman101]

Okay, when cutting the pingel pickup tubes do you cut from top of the assembly or take it apart and cut from the bottom where the pickup tubes mount to the body of the petcock?

Thank you,
Dm of mD

[Anonymous]

The tallest pipe is the main fuel supply. When the level of gas gets lower than the lowest hole on the tallest pipe you will have to go to reserve because the gas just can't get into the petcock any more. If you lower the pipe (cut it off) say 7/8 of an inch, you will have more gas in the main supply and less in the reserve. Don't cut too much off or you will have too small a researve. Try cutting it off a little at a time and then going for a ride to see where the bike starts to run out of gas. If you do the mileage calculation you will know that you want to leave maybe 3/4 of a gallon in reserve which will leave you about 30 miles max (16.5 min) 'til you're dry. This will give you a max range of about 150 miles (82.5 min). Max and min are based on the info you gave earlier.

Harrison

[chuckycheese]

Pingel

First, you need to carefully remove the screen. You can pry it off even though it's glued on. Then scrape any remaining glue from the base of the standpipe. Take you little tube cutters and measure from the top downward to determine where you want to make your cut. The more you cut off, the less reserve you'll have. As I remember, you'll have to remove at least 3/4 of an inch in order for it to fit in your tank. As I said on my previous post, I think you'll be very happy with 7/8 and you have the same gas tank I do. Using a tube cutter, you'll get a perfect, accurate cut...now you're cooking!!

Now, measure your screen in order to figure where you need to cut it. Leave it just a little bit longer than the standpipe so you can get a good attachment at the base. Carefully cut it with sharp tin snips or something else like that.

The man from Pingel sent me some epoxy to glue it back on with but mine snapped back on very securely so I didn't use it. 8)

At this point, you'll be ready to mount it into the adapter plate and put it on the bike. I used a couple of wraps of teflon tape and it's never leaked a drop. You'll have to position it just right in the tank in order to allow full range of the stick (between "off", "reserve" and "on".) :?

Lastly, put the tank back on the bike, put in a gallon of gas, put your shiny new petcock on "reserve", fire that puppy up and go for a spin! Check for leaks....if there isn't one, fill up your tank and........ride safe. 8)

Hope it works out well.

[chuckycheese]

Tallest pipe.

I'm not at all sure what Harrison's talking about because there is only ONE pipe of the petcock...not two. I think the best idea is to get it right the first time because you don't want to have to take it out over and over.....at least I wouldn't want to. Also...the less you mess with that screen, the better. :?

[Detman101]

The tallest pipe is the main fuel supply. When the level of gas gets lower than the lowest hole on the tallest pipe you will have to go to reserve because the gas just can't get into the petcock any more. If you lower the pipe (cut it off) say 7/8 of an inch, you will have more gas in the main supply and less in the reserve. Don't cut too much off or you will have too small a researve. Try cutting it off a little at a time and then going for a ride to see where the bike starts to run out of gas. If you do the mileage calculation you will know that you want to leave maybe 3/4 of a gallon in reserve which will leave you about 30 miles max (16.5 min) 'til you're dry. This will give you a max range of about 150 miles (82.5 min). Max and min are based on the info you gave earlier.

Harrison

Thanks bud!!! That will do just right!! And I won't have to spend more money on a pingel!!!
Thanks again bud. Since my stator and regulator aren't in yet...what are you doing tomorrow? hehe...


Dm of mD

[Anonymous]

Sorry, Chuck.
The small pipe on my petcock is just a screen. It goes down to the bottom of the tank as far as openings.

Damien,
I don't think I'm doing anything tomorrow. Give me a call in the AM.
BTW it is supposed to rain in the morning, but then clear up. Maybe we can take the petcock out of your bike (again) and have a look at chaging the main/reserve levels.

Harrison

[chuckycheese]

Yes

Yes, Harrison, I understand what you mean.