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gas tank size and fuel consumption.

10 posts from 5 voices
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  1. YASZ970
    #

    i asked this question awhile back with no response but.............
    my royal star has a 4.9 gallon tank and .9 gallon reserve. i have run out on purpose only to have the tank fill up at 3.5 gallons.why? someone said due to air pockets .SO WHERE IS THE OTHER 2.3 GALLONS?
    most of my miles are city miles and i get 33mpg on regular gas.it would be nice not to have to get gas every 100 miles.i hit reserve about 90 miles.
    i took out the fuel cock thinking it may have broke or is clogged.nope.all is fine with that.
    any suggestions?

  2. quicgmicg
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    Part of it is because the tank has a filler neck in it so you can't fill it all the way up. Gasoline expands a LOT when it gets hot and you need that extra space in your tank to allow for that. So even if it says 6 gallon capacity, you can't fill it all the way up.

    Do you have the bike perfectly vertical when you fill it? If it's leaning, you'll never get as much in, so that could account for a bit more.

    Also, you'll never get the last 1/2 gallon or so out of the tank under normal riding. If the Royal Star has a similar fuel shut off/reserve as the others I've seen...it will never drain out every last drop of fuel.

    Have you checked with other Royal Star owners to see what they are getting for miles per tank?

  3. tartantyger97
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    Welcome to the world of wacky electronics. I've owned my R/S Tour Deluxe for 5 years and 119,525 miles, and have yet to consume more than 3.5 gallons from the 5.5 gallon tank. On long trips through southern parts of New Mexico and Arizona, that means carrying 1-gallon reserve cans in each saddlebag, and having to store clothes and other equipment in both a trunk and a sissybar bag. Don't ask what that does for the center of gravity or low-speed handling; suffice it to say that when my destinations permit, I'm largely on interstates with gas stations at most exits. I've yet to get an explanation as to why the engine just cuts off, but now that I'm no longer protecting the warranty, I'll do some experimenting and report promising (non-warranty-voiding) discoveries.

  4. tartantyger97
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    OK, got a solution that, with some experimenting, should solve BOTH your and my problems. Removed the tank today, and discovered the fuel sender centered in the tank, atop the hump over the frame. Removed the sender (not an easy job, you gotta twist it about 30 different directions to get it out of the tank), bent the arm down slightly, reinserted, put 1 1/2 gallons in the tank and checked the fuel indicator. After three adjustments I got the indicator to register reserve level with slightly over 1 gallon in the tank. I'll test the mod on the way to Houston on either Tuesday or Wednesday and let you know how it worked.

  5. tartantyger97
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    The trip to Houston netted the following results: 1st tankful, ran to reserve indicator, drove 4.5 miles into reserve (total of 202 miles at 65-70 m.p.h), squeezed 4.45 gallons into tank with side-to-side shaking to get below fill tube. Arrived Houston 31 miles later, drove thru town to Asian market, ate, shopped, stopped at friends house in Tomball, added 3.1 gallons after only 72 miles, again side-to-side shaking to really fill tank. Left Tomball for home, drove 17.2 miles into reserve (223 miles), fill took 4.7 gallons, again shaking to fill tank. Drove home, filled from gas can, drained tank completely, measured 5.7 gallons (practical tank capacity). I did note that shaking the tank (frequently) allowed me to add .7 to .8 gallons, extending range 35-40 miles. And filling the tank when the engine (and tank) had cooled down netted a few extra miles of range, too.

  6. TheGoltj
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    i asked this question awhile back with no response but.............my...

    Part of it is that you're miscalculating the capacity of the tank. The tank has a total capacity of 4.9 gallons, of which .9 gallons is the "reserve". It's not a 4.9 gallon main tank plus a .9 gallon reserve.

    Another issue is that just because the tank is supposed to hold 4.9 gallons, doesn't necessarily mean that it will. Every tank varies just a bit. Some will hold just a bit more, most will hold just a bit less.

    There's also the possibility that there are, in fact, parts of the tank that don't fill due to air pockets. It's just the nature of a closed container where sections of it are higher than the filler tube.

    It's also possible that the fuel pump at the gas station you used was inaccurate. Yeah, they're supposed to be calibrated, but often they're not. On such a small tank, a few tenths of a gallon are real noticeable, where they might not be on a 15-20 gallon tank.

  7. tartantyger97
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    TheGoltj brings up a good point - exactly what is the capacity of the tank? My owner's manual says 5.5 gallons (2005 R/S Tour Deluxe, currently it's stated to be 5.3 gallons), the same year (and currently) the Venture was spec'd at 6 gallons. I filled the tank (with considerable "tank english", shaking side to side about every .1 gallons until I could not squeeze any more in) and from "full" to tank empty in reserve position, the most I could draw from the tank was 5.7 gallons. You might want to make the same measurement on your tank - since you have a Royal Star, capacity SHOULD exceed 5.3 gallons (smallest rated capacity I've seen on any Royal Star since 1998; the 1996-1998 non-Ventures were rated at 4.8 gallons).

  8. dabankster40
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    I have the same question. 2006 1100 vstar silverado with a 4.5 gallon tank. I am averaging 42-50 mpg, but hitting reserve around 100 miles, then adding 2-2.5 gallons when I fill up. Previous owner says he would hit reserve around 140 miles. Removed the fuel cock and it was clean. I hold the bike vertical when filling up. I'm thinking I should have a couple of gallons left in the tank and manual says reserve is 1.1 gal.

  9. TheGoltj
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    Are you sure you're really hitting reserve? Maybe you're jumping the gun a bit and don't realize it. If you don't switch the petcock, does the engine actually die? If not, you haven't hit reserve yet.

    As to filling the tank, the bike is designed to be filled with it sitting on the sidestand. It could very well be that by filling it while it's vertical, you're not putting as much gas in as you can. The reason I say that is this. When you fill the bike on the sidestand up to the bottom of the filler tube and then stand the bike up, the gas will come a good ways up the filler tube. That's actually a fair amount of extra gas that you don't put in if you just fill it to the bottom of the filler tube while it's vertical.

  10. dabankster40
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    thanks goldy. Yep, Im sure. Definitely running out of gas. I took the fuel cock out and cleaned it this weekend. It appeared to be fine. After doing that, I am at 120 miles and have not gone to reserve yet. Thats a new record for me. I will try filling it on the side stand. Buddy told me that also. Said it would help get out any air pockets since the filler neck is on the right side of the tank.

    Preciate it...

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