So I've been thinking about the VTR's fuel capacity issue...
 

...and wondering where I could fit another tank, or two.

The "problem" that first came to mind is how to maintain fuel pressure at the carbs with a remotly mounted tank. That and routing the hoses and saftey cut when the engine isn't running. I thought about it for awhile and it doesn't seem as complicated as I thought.

First thing that came to mind was a Mikuni fuel pump that runs off pulsed vacuum. They are common on snowmobiles using float-style carbs and could run off the intake port's vac line but wide open throttle may or may not provide enough pulse. (see below)

https://www.superhawkforum.com/forum...1&d=1339863567

I then drew the following image to show the remote take (wherever it may be) and the location of the pump. (see below)

https://www.superhawkforum.com/forum...1&d=1339863791

As I looked at this I -thought- (see bottom note) you wouldn't need the pump at all. The additional tank would have to be sealed which is easy enough with a weldable bung and cap for making catch-cans. The main tank would fill the remote tank and eventually make it's way to the carbs. This would work as long as the extra tank is below the main tank. The extra tank could have a transparent line from the bottom to the top to show it's fuel level. Once the idiot light comes on you'll have to keep an eye on it untill you know how long you can run on it. (see below)

https://www.superhawkforum.com/forum...1&d=1339864084

NOTE: As I think about it now, the pump would be needed because once the main tank is empty, you'd loose fuel pressure.

It's still something to think about. I'll ponder it awhile and see what I come up with.

Thought #1: Make a remote tank with a manual primer bulb that dumps into the main tank through the vent line and use it if I run out of gas. Issues: Cranking long enough for the carbs to re-fill. Gas going old. Complicated to refill.
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Put one these in a tank bag or strap it onto the pillion seat - cheap as chips :)

http://www.esellution.co.uk/media/pu...TvNTeRmgvJ.jpg

I dunno. I can get chips for $.49 at the liquer store. ;)

And then there is this option...

Or a VFR tank swap... But I guess you are looking to make things more complicated?

I've been kind of thinking about this myself and have been thinking about building an additional tank. Was thinking of just using an electric pump that some bikes use. Worked on a ZX6 the other day that had a simple pump on it. Something along those lines would probably work just fine. I'd probably find a Honda that had a similar pump just so I didn't have to put any POS kawi parts on my bike but it'd work just fine.

Thought about that too. I'd trigger the pump when the low-fuel light came on and have it run for a period long enough to empty the additional tank back into the main tank. That or manually activate it.

The advantage to having an additional tank is being able to custom form it into the chassis somehow and retain the OEM look. I saw a VFR tank swap and it just didn't look right to me.

You could have the main tank just always drain into the lower tank and the pump goes from the lower tank to the carbs. Just have the pump always supplying the fuel. Or you could have gravity feed lines from the main tank and the fuel pump lines that go from the aux tank and have the aux tank pump come on with the low fuel light. But going this route you may end up needing to use some check valves etc to make sure the fuel goes where you need it. I think the simplest way is just have the supply always coming from the aux tank and have a large hose connecting the aux and main tanks. Only thing you'd have to make sure is to give it enough time to transfer from the main to aux tank when filling so that you get a full fill up in the event the aux tank doesn't fill by the time the main tank is full and you shut off the pump.

Well my entire reply just got deleted but...yeh.

I thought a while about remote tank, decided to go with a VFR tank transplant.
5.35 gal. usable capacity
185.9 miles @34.7 mpg till bone dry
IMHO the only way to go. I'm lovin it :)

I was playing with this idea for sometime now as well, beside replacing the actual tank to a bigger one, I had this idea of adding auxiliary tank in the rear under the passenger seat made out of something like antifreeze expansion tank and have it connected directly with an open hose to the main tank, but still use a manual valve in case you want to disconnect the line,. Due to the height of the rear end, it should be working as archimedes law suggest and have the fuel balanced, kinda like the big Acerbis off road tanks, but that is just in theory. there is also the issue of the vacuum created in the auxiliary tank that you need to eliminate in order to drain it, that's where the antifreeze expansion tank idea came from... again this is just an idea

Here is an aux. tank system offered for snowmobiles that works well (based on people I have spoken to who use it):
Tour Buddy - "Your gas station on the trail" Auxiliary Fuel Systems for the touring snowmobile/ATV enthusiast

Granted, snowmobiles use a fuel pump (not gravity feed like the VTR).....

That's an interesting one! Something like that can work well, if you can fit it in the tail and you may not even need a pump.

The whole problem with an extra tank is where are you going to put it?

Under the seat? Really? I don't know about your bike but on mine I can get maybe 2 tee shirts in there, if i fold them up nice....;)

Even if you used something like the tube under a Sargent seat what would you get, maybe 1\2 a liter or so. Really not worth the effort IMHO.

I understand the sarcasm, but you can get allot more then 1/2 a liter if you modify the space under the seat and sides of the tail, maybe for someone it doe's worth the effort, I would not kill the idea and creativity that people have here as it is an on going discussion and a real need for many of the SH riders!

I guess i just don't get it, for years now VTR owners have complained about fuel distance for a tank of gas. Other select current model sportbikes only get around 100 miles before hitting reserve. This bike was intended to be a sportbike, not a touring bike. All that aside the technology of the bike is old (we all know that) but still a great bike. I guess if you are touring or live in a part of the world where gas stations are far and few between that more distance on a tank would be welcomed, otherwise i just don't see it being and issue IMHO. I just stop and put some more fuel in the tank, get a drink and head back out for more fun.

Neat idea you have though

I didn't want to start an argument about whether or not it's practical. I don't have a problem with the distance the bike can go, but many do. My personal concerns are safety and solving problems. The conversation I was trying to start was whether or not it's easily feasible and how one might go about doing it. Personally, I'd hate to have to push a 400lb bike even half a mile so unless gas stations are at 1mi increments, I wan't a manual reserve option. In a car it's alot safer to run out of gas and the light comes on 50+ miles before you're out, not 5 miles, or is it 2? 10? 14? 8? 1?. No one knows and each bike is different. Wouldn't matter if I know I have 20 miles worth of gas guaranteed in my trusty half gallon reserve tank. :)

+1. Exactly why I went the VFR tank route.

If someone really had a hard on to MOD the bike for an extra fuel tank,, a complete rework of the tail section, from moving the electronics to reshaping the under-pan, to molding a tank for the shape from fiberglass to a flexible fuel cell to a hand crafted aluminum tank might be the best location and solution.

There's a large area in front of the bike between the radiators that could hold a large amount of fuel. This link isn't the one I was looking for but there are kits that have all the bungs and a cap for DIY tanks. This one is a 3qt. BUILD YOUR OWN OIL TANK KIT Custom Motorcycle Chopper Bobber Harley Round Bag | eBay

You can use just about anything to make a tank. Maybe some 5" stainless exhaust tips for trucks. Be ingenuitive and resourceful. :)

It's not expensive or difficult to make a custom tank and if an acceptable solution is found, it's even easier to make many of them. Paint it black and it wouldn't stand out that much. Taking a few quick measurements of my bike, I can fit 2-gal in front of the engine but that would be a little complicated and have to conform around the front valve cover and require oil cooler relocation to the bottom of the tank. Also a heat shield for the front pipe. It can be done. 2-gal is a 50% improvement over stock resulting in your Hawk having >200mi range.

Personally your solution to being worried about running out of gas is kinda extreme. Are you really riding a full tank worths without stopping once? Is all that work fabbing up a reserve worth it rather than just planning a little ahead of time? I dont know about you but if Im doing a touring style ride... most of the time its planned out a bit. most of the time its riding others too so you tend to stop more.
If I absolutely needed more gas capacity for the SH, then I would go the vfr tank route. You should check into it.
but to each their own. Have fun.

So if you need to know that you gas is gone earlier, isn`t it better to get a fuel gauge, than to put additional tank and use it when you tank i empty.

As i guess the reserve indicator goes on then a certain output of the fuel level sensor.
As written in the manual -

the resistance is
4-10 ohm when the tank is full
81-91 ohm when is is emply

so all you need is an ohm meter which will show you how much fuel you have in you tank ;)

You assume the sending unit it 100% accurate for every bike made. Could be 1/2 gal left, could be 1 gal, could be empty. No way of knowing for sure unless you start with an empty tank, add X amount of fuel, and adjust the sending unit so the light comes on at X amount of fuel. The point was extending the range of the bike by adding additional fuel storage -somewhere-.

If I came to market with a $100 tank and pump and said "Here, bolt this on your bike and get another 80mile range out of it" ...I'd buy it.

Well you can buy a 19L tank from Honda or euro ebay... http://www.google.co.uk/#hl=en&newwi...w=1489&bih=949

http://www.haymouth.co.uk/phpBB3/vie...hp?f=9&t=21058

http://www.haymouth.co.uk/phpBB3/vie...=18184#p146580

It's listed as a sport-tourer, hence the cheaper insurance for most of us, especially the younger ones.

I'm usually ready to get off at 100 miles anyway. Course, I also ride the stock seat, so everyone might have different visions of what they think a ride should be. Some may want to get 200 miles before a 40 mile reserve is hit and feel like they're on a lazy boy. I like riding the stock seat and jumping off every hundred miles and step off to look at the bike real quick, just to make sure it's still a Superhawk and all...

And on trips where I'm concerned about gas stations:

http://media.rei.com/media/uu/4bb642...58ef5d5b07.jpg

I've got a couple thoughts on the capacity and want for more. First yes the overall range would be nice to be longer being most of the guys I ride with have a 150-200 mile range. Yes we usually stop about every 100 miles or less but I'm the only one that's saying "hey I need to stop by that gas station to top off again before we leave." which gets old. If I want to ride more than 100 miles I'd like to have that option. But I will say after 100 miles I'm usually ready to get off for a bit. Then you have my every day commuting. I don't commute that far to work so it's not a huge deal if I don't do any other riding, however if I'm going anywhere else besides back and forth to work it seems I'm constantly having to fill it up. Maybe even a couple times a day depending on what I'm doing. It just gets annoying that I'm stopping in the fuel stops so often. Would be nice to have a larger capacity to just have less frequency of stopping. For that guys who only ride recreationally that's probably not an issue. But I ride rain or shine. For example today it was pouring on the way in to work, I still rode.

As for the reserve tank I was thinking of building a tank that would more or less go half way around the rear shock and fit between the bottom of the tail section and the swingarm. Obviously I'd have to fab it so that the swingarm wouldn't hit at full upward travel but it seems to have a bit of room there. Was thinking just taking a chunk of 5" or 6" exhaust pipe to build the curve around the shock then build the rest of it with sheetmetal. Get a small electric pump for it and it'll be set!

Well... First off... For you that worry about how many miles/gallons do I have when the light comes on... WHY NOT FIND OUT?

It doesn't take a genoius to figure that one out, really... Put a fuel bottle like the one 7moore7 posted in your backpack, and go riding, and be nasty with the throttle... Once you're out of fuel, fill up, and go find a station... Then you know the worst case scenario, that even if you are abusing the throttle, you have X miles after the light comes on... If you're a bit more restrained, figure a bit more...

And it's been suggested by wicky already... But you can easily get 19L instead of 16L with a Euro spec tank... Or 21L with a VFR tank... A Euro spec tank will cost a pretty penny, but VFR tanks are cheap enough...

But then again, you could go the route you are all talking about... Best case scenario, I'd say you can fit roughly 1L in each side of the tail, if you make a figure following tank, and another liter or perhaps two on the middle part... Guess what... 19-20L is what that gets you... Same as the Euro spec, less than the VFR... And at this point we are talking a custom made tank or several, which will cost plenty more than any other option... And then you add hoses, valves and perhaps fuel pumps...

$100 to get the same as the VFR tank? Forget it, it's going to cost way more than that... And then, when you get that made... You still end up with several pounds worth of fuel in either a single tank or tanks all over the ass end of the bike, high up, moving around... No tank you... Pun intended...

Isn't all that space under the tail where the radiator goes? ;)

Well, that's the thing... There isn't a whole lot of space there really... A radiator fits... Barely...

Tough crowd here. lol I'll stop thinking outloud and go back to the oil thread.