Gas Tank Modification?? Can you help?

[dinkydau444]

I just bought a 97 Max, and I'm loving it! There's only one problem I have with it and that is the mileage I can get on a single tank of fuel. I get about 125 pretty regularly before I have to switch over to reserve (Though I fill up before reserve most often at around 115). This isn't a problem for me right now, but next summer it will definitely pose a problem.

I go on a ride called "Run for the Wall" which is a ride from Ontario, CA to Washington D.C. during the month of May (ends in D.C. on Memorial Day Weekend). Right now it is done by a lot of Vietnam Vets (My father included), but they really want more veterans and non veterans alike to participate. The whole point is to call attention to our POW/MIA soldiers and to making sure we do our part to bring each and every one of them home. If you want more info on the run you can go to www.RFTW.org

Thus, my predicament. Most of the rides between gas stops are about 90 miles. Some, however, go well beyond my VMax's Capabilities, so I would be forced to drop out of the group to get gas on the way. Not only that, but gas stops are run in a specific manner. When you need to get roughly 500 bikes through a gas station quickly there has to be an order to things. Bikes pull into a pump two-wide and fill from the seated position paying in cash (rounding up to the whole dollar). Since you are all Max riders you know the issue. How can I fill from under my butt!?!?!?!

Here's what Im' thinking. I'd like to find a Faux cover and convert it into an added fuel space. I'd like to take a line from the upper fuel tank and connect it to the stock fuel tank and just have the gas feed in by gravity. This way, I could not only fill the tank from the seated position (through the faux tank) but also extend my mileage. I'm aware that this will effect my center of gravity, but on the run that is not a problem. I just wont fill the upper tank when I'm not going long distance.

The run is extremely important to me, and I would love to do it on my Max. Is this even feasible??? If anyone has any ideas, please share!!!

 

[Rusty McNeil]

I just bought a 97 Max, and I'm loving it! There's only one problem I have with it and that is the mileage I can get on a single tank of fuel. I get about 125 pretty regularly before I have to switch over to reserve (Though I fill up before reserve most often at around 115). This isn't a problem for me right now, but next summer it will definitely pose a problem.

I go on a ride called "Run for the Wall" which is a ride from Ontario, CA to Washington D.C. during the month of May (ends in D.C. on Memorial Day Weekend). Right now it is done by a lot of Vietnam Vets (My father included), but they really want more veterans and non veterans alike to participate. The whole point is to call attention to our POW/MIA soldiers and to making sure we do our part to bring each and every one of them home. If you want more info on the run you can go to www.RFTW.org

Thus, my predicament. Most of the rides between gas stops are about 90 miles. Some, however, go well beyond my VMax's Capabilities, so I would be forced to drop out of the group to get gas on the way. Not only that, but gas stops are run in a specific manner. When you need to get roughly 500 bikes through a gas station quickly there has to be an order to things. Bikes pull into a pump two-wide and fill from the seated position paying in cash (rounding up to the whole dollar). Since you are all Max riders you know the issue. How can I fill from under my butt!?!?!?!

Here's what Im' thinking. I'd like to find a Faux cover and convert it into an added fuel space. I'd like to take a line from the upper fuel tank and connect it to the stock fuel tank and just have the gas feed in by gravity. This way, I could not only fill the tank from the seated position (through the faux tank) but also extend my mileage. I'm aware that this will effect my center of gravity, but on the run that is not a problem. I just wont fill the upper tank when I'm not going long distance.

The run is extremely important to me, and I would love to do it on my Max. Is this even feasible??? If anyone has any ideas, please share!!!

The early V65's had a system similiar to what you describe, whereby the faux cover tank gravity feeds to the lower tank. The gas cap was in the upper tank. It could be done but you'd have to seal off the factory cap under your butt so it wouldn't leak, and stop up the factory tank air vent and add an air vent to your upper tank.
After market faux tanks from Europe are WAY expensive, big, bulgy and ugly like a beluga head whale. If you converted your stock faux cover into a tank without re-shaping the outer skin you wouldn't add much capacity unless you ditched the air box to make more room under the cover.

Another option is an extended swing arm and an increased capacity stock tank, Sean can do them as well as PCW. There are also some sport tails that have a gas tank built in also, mostly from Europe, and expensice as well. Look on Boxxenstop or Exactrep for the Manufactured versions of these.

I simply put a one gallon can in my saddle bags when this comes up for me, but that wouldn't fill you up, I just do it to keep from getting starnded in West Texas where the gas stations can be several hundred miles apart.

 

[one2dmax]

There are aftermarket tanks for just this exact situation. You can either get a rear seat version or a new faux tank cover version. We painted one for a customer a couple of years ago (pics of the tank are in our facebook site)

Sean

 

[misiek93]

I just bought a 97 Max, and I'm loving it! There's only one problem I have with it and that is the mileage I can get on a single tank of fuel. I get about 125 pretty regularly before I have to switch over to reserve (Though I fill up before reserve most often at around 115). This isn't a problem for me right now, but next summer it will definitely pose a problem.

I go on a ride called "Run for the Wall" which is a ride from Ontario, CA to Washington D.C. during the month of May (ends in D.C. on Memorial Day Weekend). Right now it is done by a lot of Vietnam Vets (My father included), but they really want more veterans and non veterans alike to participate. The whole point is to call attention to our POW/MIA soldiers and to making sure we do our part to bring each and every one of them home. If you want more info on the run you can go to www.RFTW.org

Thus, my predicament. Most of the rides between gas stops are about 90 miles. Some, however, go well beyond my VMax's Capabilities, so I would be forced to drop out of the group to get gas on the way. Not only that, but gas stops are run in a specific manner. When you need to get roughly 500 bikes through a gas station quickly there has to be an order to things. Bikes pull into a pump two-wide and fill from the seated position paying in cash (rounding up to the whole dollar). Since you are all Max riders you know the issue. How can I fill from under my butt!?!?!?!

Here's what Im' thinking. I'd like to find a Faux cover and convert it into an added fuel space. I'd like to take a line from the upper fuel tank and connect it to the stock fuel tank and just have the gas feed in by gravity. This way, I could not only fill the tank from the seated position (through the faux tank) but also extend my mileage. I'm aware that this will effect my center of gravity, but on the run that is not a problem. I just wont fill the upper tank when I'm not going long distance.

The run is extremely important to me, and I would love to do it on my Max. Is this even feasible??? If anyone has any ideas, please share!!!

There is realy no easy/cheap way to do this. I've been looking for extra tanks myself for a while but I can't justify the cost for little gain. You can look into getting a venture diff which changes your gear ratio, you'll get few more miles out of it that way.

Also, I'm sure the organizers will let you get off your bike (or at least lift your butt) to fill it up with gas since that's the ONLY way to put gas in our bikes. if not you can always use a different fuel pump. I don't think the gas station will let you guys take over every pump. I've been on one ride like that, with "strict" fueling rules and that was never an issue.

Or you can add an external fuel can behind the seat if you have a luggage rack. I've seen it done on a gen II, few people questioned the safety aspect of this set up with the tank exposed like that but it deffinitelly increases fuel capacity and range.

http://www.google.com/imgres?q=vmax...art=0&ndsp=18&ved=1t:429,r:3,s:0&tx=102&ty=54

Just my .02 cents

 

[Rollie]

Check out our own Miles Long gallery on the forum. He has fabbed up an extended tank.

 

[maxcruiser]

Not sure if this will work for ya, but I had a tour tank that mounted to the passenger back rest. Nice thing is you can easily take it off when not needed. This tank feeds into the main tank.

http://www.tourtank.com/

Thought I would throw out another option for you.

Mike

 

[wildweasel_pt]

Get a used tank of your choice, ditch the scoops and taylor the tank to fit the max. I have a 40ltr + tank on mine, i can make more than 650kms with it... The tank goes underneath the seat but the bike is pretty well modded, including frame. I will do an aux tank on my other bike using the spare space the FCRs will give me. I will link both tanks and still gonna extend my stock tank (im using extended SA). But this will only happen after i get my manifolds sorted out and the carbs running...

 

[a113ycat]

I saw a photo on I believe the UFO site where someone had added the Ram air system on their Max and removed the airbox completely the made an aluminum Custom fit tank the mounted right under the faux tank cover. It looked pretty cool and probably added a good deal to his mileage range. Plus you reatin the V-Max look. I looked and looked and now I cant find the link

 

[dinkydau444]

Thanks for the input everybody! I knew I could count on the forum to help out! I spoke with John from RMSportMax, and he suggested going with a Royal Star rear diff if I'm looking to just push the mileage over 150... I'm probably going to go this route, but that still leaves me with the problem of gassing up in line.

Do you think it would be feasible to extend the gas tank nozzle so that it is in front of me? I was thinking there might be enough room under the stock faux cover... Or I could just slightly modify the cover (raise the middle a bit) to allow room for a cylinder to run up it to a new gas cap? I'd have to seal off the old air vent and make a new one but that doesn't seem like too much work...

What'dya all think?

 

[[email protected]]

From what I've read on here, forum members with the venture or royal star differential are not getting that much better MPG than a stock vmax. And the big question.....Whats the point of having a vmax if you do mods to LOSE acceleration?!

I say go for a 3" stretch on the swingarm. Braced and notched. Then have the tank enlarged for another gallon of fuel.

Lets weight out the pro's and cons:

Differential swap
Pros:
-cheaper at $400 plus shipping.
-You gain top end speed IF your bike has the power to pull the taller gears
-Cruise rpm is lowered approx 10%

Cons:
-It doesn't raise your MPG much at all.
-You lose acceleration
-It doesn't make you tank any bigger!

Extended Swingarm/ expanded fuel tank
Pros:
-braced arm= better handling. Something ever vmaxer wants
-room for a wider tire down the road if you decide to do it
-you gain 1 gallon of fuel capacity. 30-40 more miles depending on your tune
-it looks cool

Cons
-more expensive. From Sean the cost is approximately $1,000 with the shaft extension (not a new HD shaft from Furber), powdercoat, bearings/seals and brake line
Other than cost, I don't see any more cons....

 

[dinkydau444]

The swingarm idea is great, but I really can't see myself spending a grand for a gallon more of fuel... I was hoping to find a relatively cheap (under 500) way of doing this. For $1000 I'll make extra gas stops and deal with the craziness of trying to get back in my spot...

 

[wildweasel_pt]

What i'd do would be to get a extension hose from the filler neck and route it to the rear seat. Get a stock seat cowling and then bolt one of those alloy tank lids like on sportbikes and you can fill your tank from there. If you fill it to the top you'll gain a couple liters more, easy and cheap, and good looking, see below...

 

[redgambler]

I thought that I saw replacement tanks that hold more fuel. That must not work on the stock bike. Thought I seen 7 gallon compasity.

 

[wildweasel_pt]

I thought that I saw replacement tanks that hold more fuel. That must not work on the stock bike. Thought I seen 7 gallon compasity.

Replacement tanks that hold 7 gallons is impossible, nothing that holds that amount can be fitted in there, even with the battery box removed, you are talking of about 26.5 liters and the stock tank has 15 liters max so 4 gallons, almost half you claim. That can only be achieved with aux tank or with heavy frame modding

 

[Vmaxattacks]

Don't complain. I get 90 miles before I have to hit reserve :bang head:

 

[Miles Long]

Thanks for the input everybody! I knew I could count on the forum to help out! I spoke with John from RMSportMax, and he suggested going with a Royal Star rear diff if I'm looking to just push the mileage over 150... I'm probably going to go this route, but that still leaves me with the problem of gassing up in line.

Do you think it would be feasible to extend the gas tank nozzle so that it is in front of me? I was thinking there might be enough room under the stock faux cover... Or I could just slightly modify the cover (raise the middle a bit) to allow room for a cylinder to run up it to a new gas cap? I'd have to seal off the old air vent and make a new one but that doesn't seem like too much work...

What'dya all think?

This might sound strange, but I wish I was faced with your problem! I'd love the challenge of a front-mounted REAL gas tank!
Constructing a gas tank to replace the faux tank would not be that difficult, the tricky part would be connecting the outlet to the existing filler pipe - there simply is not that much room, and would require some severe bends in the new piping, which likely would restrict the delivery of the fuel into the lower tank. For these reasons I believe a top-mounted tank would have to be connected to the fuel pump line, therefore making it a pony tank only - you would still have to fill the under-seat tank in the conventional way.
I have never been involved in an organized ride like you are describing, and I can't imagine being so rushed that I'd have to fuel up while still seated, even if that was possible with a Max. But "to each their own", and you have made it clear that participating is very important to you, so.....
in my opinion your best bet would be one of the tanks already described or linked, one that replaces the rear seat or is mounted on a rack, AND fed directly into the existing tank. I'm sure your fellow riders would understand, when you got off your bike to refuel(and maybe stretch the legs?)
I have made two direct-feed tanks, one that fits under the rear seat,for the "street" version of my bike, and a larger one that replaces the seat, for the touring version. Both have their own vent and tip-over valve arrangements, which replace the original vent line. Both were constucted of heavy-wall sheet metal, mig welded at the seams.
If you do decide to go with a rear mounted custom tank, let me know. I might be able to help you with some of the details.
Cheers, and good luck!

 

[dinkydau444]

This might sound strange, but I wish I was faced with your problem! I'd love the challenge of a front-mounted REAL gas tank!
Constructing a gas tank to replace the faux tank would not be that difficult, the tricky part would be connecting the outlet to the existing filler pipe - there simply is not that much room, and would require some severe bends in the new piping, which likely would restrict the delivery of the fuel into the lower tank. For these reasons I believe a top-mounted tank would have to be connected to the fuel pump line, therefore making it a pony tank only - you would still have to fill the under-seat tank in the conventional way.
I have never been involved in an organized ride like you are describing, and I can't imagine being so rushed that I'd have to fuel up while still seated, even if that was possible with a Max. But "to each their own", and you have made it clear that participating is very important to you, so.....
in my opinion your best bet would be one of the tanks already described or linked, one that replaces the rear seat or is mounted on a rack, AND fed directly into the existing tank. I'm sure your fellow riders would understand, when you got off your bike to refuel(and maybe stretch the legs?)
I have made two direct-feed tanks, one that fits under the rear seat,for the "street" version of my bike, and a larger one that replaces the seat, for the touring version. Both have their own vent and tip-over valve arrangements, which replace the original vent line. Both were constucted of heavy-wall sheet metal, mig welded at the seams.
If you do decide to go with a rear mounted custom tank, let me know. I might be able to help you with some of the details.
Cheers, and good luck!

I have looked at your setup, and I am incredibly impressed. It's absolutely genius what you've done with the rear seat setup. After thinking more about the whole situation, I've decided that going on the "Run" the typical way is just not worth the money I would invest in fabrication or on a new rear diff. I think I will be getting an aux tank (tour tank?) and put it on a luggage rack. 2 gallons should be plenty, especially going 65 mph most of the way. I'll just have to do some advanced planning, so I know when to pull out and hit my own gas stop. Shouldn't happen often enough to really put me down. Heck, the money I save doing this can go toward a windshield for the trip!

 

[wildweasel_pt]

This might sound strange, but I wish I was faced with your problem! I'd love the challenge of a front-mounted REAL gas tank!
Constructing a gas tank to replace the faux tank would not be that difficult, the tricky part would be connecting the outlet to the existing filler pipe - there simply is not that much room, and would require some severe bends in the new piping, which likely would restrict the delivery of the fuel into the lower tank. For these reasons I believe a top-mounted tank would have to be connected to the fuel pump line, therefore making it a pony tank only - you would still have to fill the under-seat tank in the conventional way.
I have never been involved in an organized ride like you are describing, and I can't imagine being so rushed that I'd have to fuel up while still seated, even if that was possible with a Max. But "to each their own", and you have made it clear that participating is very important to you, so.....
in my opinion your best bet would be one of the tanks already described or linked, one that replaces the rear seat or is mounted on a rack, AND fed directly into the existing tank. I'm sure your fellow riders would understand, when you got off your bike to refuel(and maybe stretch the legs?)
I have made two direct-feed tanks, one that fits under the rear seat,for the "street" version of my bike, and a larger one that replaces the seat, for the touring version. Both have their own vent and tip-over valve arrangements, which replace the original vent line. Both were constucted of heavy-wall sheet metal, mig welded at the seams.
If you do decide to go with a rear mounted custom tank, let me know. I might be able to help you with some of the details.
Cheers, and good luck!

Mate

My plan is to use 2 hoses. One for filling and the other one to let the air come out, this way you can use thinner hoses (1"?), That second hose will work as vent as well with a T splitter on top with a one way (inwards for venting) air checkvalve and the other tip connected to the aux tank (for refilling - circulate the air when fuel is draining from aux tank to main tank through the refilling connector hose). I hope you can picture all this... This will be my setup, and im almost sure will work fine. Just need to do some tweaking on the stock tank to close the filler, expand it and setup the 2 connectors for the hoses...

 

[Rollie]

Pre-arrange with the organizers in advance regarding the fuel stops so you are the last in line to get gas. Few would care then if you had to dismount to fill up .

It usually takes a minute or two extra anyway for word to get back up front that all are filled & ready to go. unk:

 

[Miles Long]

I have looked at your setup, and I am incredibly impressed. It's absolutely genius what you've done with the rear seat setup. After thinking more about the whole situation, I've decided that going on the "Run" the typical way is just not worth the money I would invest in fabrication or on a new rear diff. I think I will be getting an aux tank (tour tank?) and put it on a luggage rack. 2 gallons should be plenty, especially going 65 mph most of the way. I'll just have to do some advanced planning, so I know when to pull out and hit my own gas stop. Shouldn't happen often enough to really put me down. Heck, the money I save doing this can go toward a windshield for the trip!

Thanks for the kind words about my setup.
As for your situation, I took a closer look at the "Tourtank" website, that Maxcruiser had linked for you in an earlier response. I am very impressed!
Aircraft aluminum(light and non-corrosive) lots of configurations available, cool accessories, inexpensive(seems too good to be true),and the best part - made in the USA.
However, I see one problem - all the configurations show small outlet(s) designed for fuel lines, to be tied in with existing lines on the bike. This would certainly work with the Vmax (Maxcruiser could fill you in on the details about hookup), but you would still wind up with a ponytank arrangment, requiring the filling of two tanks during gas stops.
The manufacturer seems to be quite flexible regarding customizing each tank for the intended model. See the "Install" link on the website, that includes it's own link to a chatforum, and a "contact us" page, where you can sketch out what you want using the Paint program.
Also check out the "Customers" link. Lots of photos of different setups, many using a rear rack. Also, see the "Parts" link. There is a nylon cover available for all sizes of tanks, that makes it look like a bedroll. Way groovy!

With all the above in mind, this is what I envision (pardon me for being long-winded, but custom fabrication gets me really excited! My palms are sweating, my pulse rate is thru the roof!)

I'd skip the rack mounting. The rack designed for the OEM sissybar is way too small for a tank. Even if you had a larger rack made up to fit your bike, I would save this space for a kitbag. If you are doing a cross-country tour, you will need lots of space for goodies. Trust me, I know. Also, the extra weight of the fuel is best kept as forward as possible, closer to the bike's c.o.g.
I assuming you will be riding solo. I would fabricate a sheet-metal cover that approximates the size and shape of the outer dimensions of the passenger seat, with tabs to fasten it to the bike, in the original locations of the seat. On the top of this cover, I would mount the tank, using the included straps. Here comes the custom part - instead of the small fuel line outlet, I would have the tank equipped with a centre-mounted 11/2" female threaded bung, or a 90 degree elbow, with a hose barb on the outlet. Actual sizing of the fitting would depend on the I.D. of the short section of gas-resistant hose that you use. Marine supply shops may help you here. Inboard motors use a gas and oil resistant hose for the engine exhaust, and probably have a variety of fittings as well. I wouldn't go much smaller than 11/2" or 11/4" hose. You don't want to restrict the fuel when filling up, which would slow the process.
To connect to the bike's filler pipe, I used a 11/2" 45 degree PVC elbow, with a rubber union and hose clamps. Don't use ABS fittings - that material reacts with gasoline. Of course the other end of the elbow would have to be fitted with a piece of PVC pipe, or a bushing and nipple, something that will fit inside the gas hose. Depending on the length and type of hose used, this arrangment would provide flexibility when hooking up the cover/gas tank assembly, at the filler pipe end. To install , you may have to remove the rider's seat, or maybe just flip the centre section back. In my case, this gives me enough room to get at the hose clamps.
For the Tourtank's filler location, I would opt for a left-hand end mount, for a few reasons. The end mount would allow you to pile gear on top of the tank, without messing up the filler location. And having the filler on the sidestand side means more convinence when you dismount. Also, because the bike will have a lean to it, you don't have to worry about overfilling. Just fill to the lip. When the bike is uprighted, you will have space at the top of the tank. For this reason, I would get the 3.5. gallon tank (8"x 20") This size will almost double your present capacity, and range!
I suggest that you E-mail the company, see what they think about a direct-filling tank, with a larger outlet size. Hell, they may have even made up tanks for V-maxes already!
Cheers, keep us posted
p.s. - got your P.M. re the fairing. I'll reply soon, after I've checked out some websites.