For most of us, once we decide to adapt our bikes for a really long trip, the first thing we think is: we’re gonna need a bigger tank.
Below I list most of the options (it’s also in AMH7  pp66-68). Feel free to add your ideas and solutions to the comments below.

How much range do you need?
Having done my share of travel in remote areas, in my opinion on a bike a maximum potential range of 250 miles of 400km is plenty. There will be very few occasions when you’ll need more, and at that time a temporary solution (see below) may do the trick. As it is, the proliferation of car ownership across the developing world has seen a commensurate increase in fuel stations compared to when I first starting travelling by bike. Most of the time half that recommended range will get you to the next servo.

Saving fuel
The simplest way to maximise your range is of course to ride economically and/or choose an economical machine. In my experience any sized bike ridden at around 55mph/90kph will return optimal fuel consumption. Experienced overlanders will know that driving standards and road surfaces being what they are, 60mph is a practical top speed out in the AMZ. On the right, a conversion table for those of you who don’t speak UKmpg or kpl.
Riding economically on a 660Z Tenere (left) one night in Morocco I got a record 86.8mpg, and that included crossing the High Atlas. On an F650GS twin the best was 80. With a CRF250L I topped out at 98.5 and on my recent CB500X it was 93.5mpg.
These are all staggering figures compared to the bikes I rode in the 80s and it’s mostly because they all use efi. Added with other advances in motorcycle engine technology, electronic fuel injection is far more efficient, less fussy and more reliable than a carburettor, and it continues to improve year by year.
Of course trundling along at 55mph, saving the planet for your children and your children’s children can get frustrating on a Triumph Tiger 800 XC, if not outright unnerving on a busy, fast road. One of the pleasures of quiet backroads is that you can ride your bike at its own natural pace without other vehicles breathing down your neck or getting in your way.
Other ways of saving fuel include running smooth tread-pattern road tyres at maximum recommenced pressures, as well as minimising the frontal profile of your bike (though this only really matters at higher speeds). Overtake smoothly, brake moderately and generally try to maintain a steady momentum at a smooth pace rather than racing from bend to bend or truck to truck. If you’ve a choice, avoid the lowest octane fuel in a bid to save a few pennies. I’ve found it can be a false economy. It goes without saying that your bike wants to be in good shape with a nicely lubed chain.
When things get desperate – we’ve all been there – coast in neutral down long descents while remembering that without engine braking your brakes may overheat on a very long switchback descent. Unless every drop matters, better do this with the engine ticking over in neutral so your lights, ABS and anything else works like it should. Engine on or off, on off-road descents be careful not to knock the bike into gear.
One thing I’ve done on most of my bikes is make a throttle position marker on the throttle body (left) with tippex or tape so it’s easy to tell at a glance if you’re WFO. Tucked behind an effective screen on a powerful bike, it’s not always possible to notice a strong headwind or a gradient and how the throttle has crept open to deal with them. Very often closing the throttle a lot will barely lose you any speed, but saves a whole lot of fuel.

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Is a small bike really more economical?

Most 250 road and trail bikes today could return 100mpg. A 125 ought to exceed that but for most riders I believe a 250 is the smallest practical capacity for overland travel once you load it up and add some mountains, busy traffic and headwinds. What’s interesting is that my 2012 250L’s cruised at 60mph with little left (especially at altitude), while the 500X cruised at 70-75 where possible with more to spare. And yet peak mpg was within 5% and the average was only some 15% better on the CRF (once I returned the fuel controller). But I bet if I’d run my 500 at 250 speeds that gap would have narrowed. Any 500 is largely immune to gradients, headwinds, loads or your impatience. At times on the 250 I was stuck at 50-55 with nothing left for overtaking which in its way can be quite tiring.
The 250’s real benefits are clear: lower purchase price and insurance and not least the much lighter weight (reduced shipping costs, easier picking up, less intimidating off-road). For a light- or off-road focussed rider a 250’s a great choice for a travel bike. Me, I’d love to see a CRF450L and I’ll keep saying that until they make one.

• Capacity: 250cc vs 471cc
• Fuel capacity: 7.8L vx 17.5L
• Claimed power: 24hp vs 47hp
• OE wet weight: 146kg vs 197kg
• My cruising speed: 60 vs 70-75mph
• Av. fuel consumption: 86.7mpg vs 74mpg
• OE max fuel range: 140m/270m

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Extending your range
When it comes to extending range, most of the time we’re balancing convenience with the cost, weight and bulk of carrying extra fuel. Bulk is a factor on a small bike. Weight matters too if you’re planning on riding on dirt. And to some cost matters more than others, but with bigger tanks it pays not to think too hard about capacity increase vs cost because you will always lose. For a long trip it’s more about convenience – knowing you can get from A to B without needing to fill up, even if you do stop frequently anyway to take pictures or smell the roses. Aside from doing all the right things as listed above, here are the options to carry more fuel:

• Fit a bigger aftermarket tank
• Enlarge the OE tank or make a bigger one
• Carry or mount extra fuel containers, rigid or collapsible
• Procure temporary/disposable containers

Bigger aftermarket tanks
In Europe Acerbis made their name supplying big plastic for the original Dakar Rally, but haven’t really developed new tanks in years. In the US there’s Clarke and IMS and in Australia Aqualine/Safari serve desert racers who’ve grown into adv riders. IMS and Safari are more on the case; there’s also Touratech plus some smaller, specialist outfitters.
But if you can, buy a bike with a big tank (or useful range) in the first place. Anything with more than 15 litres should do and, along with the beak, this is one of the genuinely useful features of your so-called adventure bike, though good fuel range is more common on bigger capacity machines. The current R1200GS Adventure comes with a 30-litre tank which could return 375 miles/600km at 60mpg – something you’d hope must be possible on the LC.
On the left, my XT600Z in 1985. I got 80mpg one day in Mali, slumped over the tank with a backwind and the shits. With the 30-litre OE tank that could have potentially added up to a staggering 840 clicks or well over 500 miles. And yet that bike weighed under 150kg, unloaded. On that trip I still carried a 10-litre jerry to cross the Sahara where 80mpg would be hard to achieve on the sands.

Once you get over the cost, the best thing with a replacement tank is that it puts the extra bulk in the best place to have a minimum impact on the bike. All you get is a heavier machine when full, but if it’s well designed, you knees won’t be splayed like a gerbil on a dissection table.

Tiny tanks are the bane of many urban bikes like the BMW G650 X bikes and the Husky Terra, or dirt-oriented 250s like CRFs, WR-Rs and KLX-Ss – these bikes all come with tanks at around 7 litres out of the crate which makes for great ‘wet’ weight figures.
You can add the KTM 690/Husky 701 (left; 12.9 litres) to that list too. Once 690s were recognised as the ‘new Tenere’, Rally Raid made their name supplying extra capacity tankage.
Especially in the UK (most plastic tanks are produced elsewhere) it’s the cost of a bigger tank that can make it hard to justify. Would you pay £500 in the UK to double the capacity of your WR250R/X to 14 litres (currently £310 in Ozzie)?
Part of the reason they’re expensive it that it takes a lot of work to design a rotomoulded plastic tank to fit a given bike, and they’re only ever going to sell a few hundred. On the right a curvaceous 18-litre tank for a WR250R from IMS. A substantial 250% increase in capacity for a fairly reasonable $400 (plus shipping and taxes to anywhere else). I used one myself and didn’t regret the expense. Anyway, I had no choice.

Enlarge, adapt or make a bigger tank
The mark ups as mentioned above are what compel riders to find other solutions. In the old days before plastic tanks became road legal in Europe, it was common to get your own metal tank made, or to enlarge the original, very often by simply cutting and welding another on top. It didn’t win any design awards but it got the job done.
For my first desert bike (left), an XT500 (9-litre tank), the only choice was get one made in alloy which is easier to fabricate and weld than steel. Others made tanks in fibreglass before kevlar came along. Alloy doesn’t cope so well with the vibration that an XT500 riding over corrugations puts out. Or in my case, that lack of know-how about sturdy tank mounts vs terrain and coarse suspension meant they broke, the loose tank cracked, and it was game over (right) in the middle of nowhere. That’s why I thought the original Tenere XT600Z pictured above was such a great bike – no need to re-invent the wheel for long-range desert biking.

For some, the 23-litres of the later twinlamp Tenere was not enough. Above, the 3AJ has had a pair of 20-litre jerries morphed onto the tank sides making 40 litres. You’d imagine a potential range of up to a 1000km at 70mpg, but all that weight sloshing around up there can get the better of you (right).

One good thing about enlarging what you have is that you keep the mounts and these days – the fuel pump fitting. It’s not just a hose from the fuel tap to the carb anymore.
Just don’t forget the extra weight pressing on those tank mounts (especially off-road) and, where relevant, the need to keep the level above the main fuel pump or resort to extra pump/s to suck from below, as the black IMS tank above does. Efi or carb, fuel pumps don’t use much juice and are easy to replace, so better to suck low than have the mass of the added weight above the main pump or the carb, like early Dakar racers (right).

All this faffing about with metal – ferrous or otherwise – is why plastic tanks are such a good idea. They’re immune to vibration fractures, oxidation, denting and they give a bit on impacts which spares the mounts, all while being easy to repair reliably with glue. And translucent options allow you to see how the fuel level is doing.
Again, in the pre-efi era, you could bodge on any Acerbis that would almost fit as long as the fuel line reached the carb and nothing rubbed. Right, we shoehorned Acerbis XR600 ’40-litre’ Dakar tanks onto our Desert Riders XR650Ls which came with a poxy 11-litre tank (right).
That still didn’t give anywhere near the range we needed so we carried more and buried fuel caches in the desert. I wouldn’t go with all that weight up there again. I’d sooner get 20 litres and 2 x 10 on the side or at the back, but you can see the temptation to get the stuff out of the way in one location.
One tip I learned with the huge tanks on these XRLs: the tank sits midway so upgrade the suspension on both ends to deal with the weight, not just the front. And other riders found that pressing in concavities on the underside of a plastic tank with a hot spoon can help the tank fit better or sit lower.

Extra tanks and fuel containers
One of the cleverest things about my BMW XCountry (left; av. mpg 74) was the Xtank made by Erik in NL and mounted opposite the hefty silencer on the right. A simple tube taken from the inadequate 9.5-litre underseat tank’s vacuum feed sucked fuel from the Xtank into the main tank and created a seamless syphon. Result: the modest range was increased to around 220 miles with no extra pumps or taps needed. My message to riders with underseat tanks: consider a similar arrangement for your bike – even with a much cheaper Rotopax or similar; it’s such an easy job. Any auxiliary tank that’s permanently mounted but not plumbed in is less useful. If that’s what works, best consider a switched fuel pump into the main tank.

Demountable containers
This is by far the cheapest solution. On the KLX, left, with its tiny 7-litre tank, a NoSpill 1.25 US gas can from Walmart (takes 1.5 US or 5.7L) gave me an adequate 200-mile range. I relied on that can a lot on that trip and the twenty bucks was a lot less than the $275 I could have spent on an IMS tank, gaining only 4.2 litres.
Again on the left, my Funduro in Libya has an Acerbis tank of around 20 litres, but I still needed a red can job on the back, and even then, ran out once we lost track and drifted into the dunes (picture, top of the page).
On the right, the Reda 1USgal gas can ($30) designed for backswept Harley saddlebags, but here you can see might slot onto a KLX once the seat was trimmed. Giant Loop also suggest it could fit neatly into one of their tank bags. I find this front-of-seat space is often wasted on these dirt-styled 250s. Or a real MXer you’d slide onto the tank to help the bike carve through berms, but on the road to Machu Picchu you’re just looking to get there before nightfall.

In Germany Hunersdorff make lots of handy plastic fuel cans, including Fuel Friends. Zen Overland and Touratech sell the boxy 2- and rounded 3-litre cans (right) from £14, as well as pricey mounting brackets for the boxy 2L. The 2 litres are also sold for £11 on ebay by this scooter place. Make sure you get the petrol ones with the strap retaining thing (left) to aid secure mounting. I’m mounting two inside the rack of my WR for water. The more-rounded three litre is a bit harder to fix to a flat surface. Fuel Friends also make a 1.5l  can (right) with a waisted profile for secure strapping. Zen sells these too.

The well-known Rotopax series of storage cans (most usefully on a bike: 1US gal, 1.75 (left) and 2 gal – or 3.8 litres, 6.6 and 7.5) are flat slabs that are easier to pack and mount. Kolpin are similar but cheaper and some say less leakproof.
Once full of petrol and shaking about, a flat slab plastic container would ordinarily balloon out, stress the seams and probably burst. That’s why metal jerricans have that ‘X’ in the sides to allow for stress-reduced bulging. Rotopax and Kolpin got round this limitation in plastic by containing the two slab sides with a central hole, and then using that hole as an ingenious mounting device. Rotopax especially may cost several times the price of a regular Walmart/Halfords fuel can in a similar size, and for the space they take up, are inefficient, but that doesn’t stop everyone on advrider clamping them all over their rigs.

Cheap (or not) plastic cans have pretty much replaced inexpensive classic steel jerricans for use on a motorcycle, as is happening with fuel tanks. Over the years I’ve used heavy 20-litre and ten-litre jerries to extend my range. The good thing was they were cheap, robust, could be sold on locally, made good bike stands, seats and so on, but were heavy and took up room.

As well as plastic cans, we now have fuel bags or bladders. Either use-once emergency containers like the €9 Wunderlich bag on the left, to rugged vinyl bladders of up to 800,000 litres from outfits like Liquid Containment in Australia. The  great thing is that they take little space when empty but being wobbly blobs, can be hard to attach to a bike when bouncing around off-road. Once there’s space up front in the main tank, decant and roll up the bag out of the way. On the right, an older 7-litre bladder from Liquid C with an integrated spout. the current version holds 10 or 15  litres and both go for AUS120 (about 62 quid). There are Chinese -made copies around, but I’d still take one of these over the same capacity in Rotopax any day. Watch the rubber o-ring seal doesn’t fall out of the cap, as happened to me on a windy Nevada day once. I used an old 10L LC bladder  (left) on recent Morocco trips rolled up behind the rack. Never needed to use it but sure glad it was there.
Similar to the LC bladders is the Desert Fox 5-litre fuel cell sold in RSA for R685 (£36) but with lot of handy lashing points. In Ozzie it goes from AUD99 up, but is only rated for ‘offroad and racing use’ and temporary storage. You do wonder what the actual bladder inside is made of – hopefully something more than a Wunderlich-type bag – but it’s all encased in what looks like a tough canvas exterior which ought to protect it. The nozzle eliminates the need for a funnel and stores in a pocket alongside the spout.
In the UK this place sells new ’20L’ Swiss army water bags which I’ve used for water on desert car trips (left; actually more like 18L). The rubber is rugged but the handle eyelets can rip out and the press-button spring-loaded tap may leak under fuel pressure for which they’re clearly not designed. For 17 quid it could be worth a try.

I’ve also long used lighter MSR Dromedary bags for water but this WR guy has used them as fuel bladders on his trip, seemingly without spontaneous combustion.
In dire straits many of us have resorted to using PET drinks bottles or similar, often found by the roadside. Like I say in the book, buy the slightly more durable fizzy drink ones but don’t expect too much of them and keep them out of a hot sun. They can burst on the slightest jolt so treat them as disposables and dispose of them quickly.

Depends where it happens of course, but running out of fuel can lead to unscripted adventures and memorable encounters. I can’t say I was glad to meet the two sleazy guys who gave me a lift one night in northwest Algeria after my XT500 ran dry. But I got to town and returned next day at 100mph in a local sheikh’s Range Rover. As we all know, whatever size tank you run you’ll run out if you misjudge it or push your luck as I did that night. On most other days it’s convenience and peace of mind that a useful fuel range can give to a long ride.