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Discussion Starter #1
About to get a 10 gallon IMS tank and wondering if it will clear my Thermobob2? Anyone have experience with this on a 2nd Gen KLR?
 

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Peter has a Thermo-Bob, I'm pretty sure!



But, NedQuick; do you really NEED a 10-gallon tank? Why? (Just curious; inquiring minds want to know! :))

Peter said the extra capacity was useful to him in South America, able to bypass the side-of-the-road locals selling gasoline from plastic jugs, and motor on to civilization sufficient to harbor service stations. Regardless, from the Arctic Circle to Tierra del Fuego, he was never in a situation where the extra capacity was necessary to keep him from being totally stranded from lack of fuel; gasoline in some form was always proximately available.

He DID run out of gas on the way from the Washington, DC, area to Florida, however! It was only on one side, but . . . somehow, when one side's dry, the other side's not accessible, vacuum-powered lift pump notwithstanding. (Please don't ask me to explain; I do not understand, either!)

Oh, yes: If your Thermo-Bob an original, or a Thermo-Bob 2? Clearance issues may vary between those generations.

Ah, the Thermo-Bob! Stabilizes coolant more fully, and at a higher temperature than the stock system. Resulting in (fill in this blank) :).
 

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Discussion Starter #3
I planning to ride the TCAT (Trans Canada Adventure Trail) and on the Labrador Hwy there are some very long distances without fuel. Two other reasons for the tank however: 1) I can get it at a very attractive price (never used by a friend who was planning a big trip) and 2) I don't plan to put more than 5 or 6 gallons of fuel in it most of the time, which will result in a lower centre of gravity when riding.

However, if it won't mount with my thermobob 2, I may have to reconsider.

By the way, I'm looking for fellow adventure seekers interested in the trip. (date isn't cast in stone yet, but probably July 2016) Info on the route can be found at graveltravel.ca
 

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NedQuick-

There is 3/4" of clearance between the stock thermostat housing and the tank. Bill would have to tell you what the thickness of the T-Bob-2 is in order for you to determine if it will fit.

Damocles - The IMS10 is a study in contrasts; a brilliant concept hobbled by poor design and execution.

I will not wax eloquent regarding why the IMS10 is the only device using the Mikuni vacuum pump where the vacuum pump is prone to failure, but I will explain why it runs out of gas with plenty left inside.

The pump is, of course, operated by engine vacuum. It's delivery rate is not very high, but is more than sufficient for the KLR's maximum fuel needs. The input to the pump is two lines coming together in a 'Y' formation. There is a pickup line that goes down to the bottom of each of the wings. The fuel is drawn equally from each side. The output of the pump dumps into a well on the left side; the well surrounds the petcock's inlet tubes.

The carburetor draws what it needs, which is considerably less than the pump's output. The excess simply overflows the well and re-fills the left wing. The end result is that far more fuel is drawn from the right wing, as none of the overflow replenishes that side.

Since the pump's pick up lines are Siamesed, once one tube starts to suck air the pump will deliver no more fuel. This abandons whatever fuel is remaining in the left wing.

The odd thing is that the tank operates as a gravity-fed tank for the first 7-8 gallons (depending on the amount of sloshing that can keep the sell filled - my tests shows close to 8 gallons), Thus the pump is needed only for the last 2-3 gallons yet it runs all the time.

Reports of pump failures are not unknown and it is my opinion that the failures are heat related. Owners are well advised to carry a pump rebuild kit.

I am changing the plumbing in mine to equalize the overflow into both the right and left wings and have converted to an external electric pump.

As to 'Why get an IMS10?' I would offer that the tank, filled with 6 gallons of gas, weighs considerably less than the stock tank plus guards and does a better job of protecting the stuff that engine guards are supposed to protect. It carries the stock amount of gas much lower on the bike, too. That's probably the best use for the thing, as there isn't a road in North America that the stock KLR can't travel without running out of gas (there may be a road in Canada that is ~250 miles with no gas, not entirely sure about that).

Of course, if one is going to be running long distances off-road the additional four gallons would be very handy.

Tom
 

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Discussion Starter #5
Thanks for the info Tom. In my research I haven't found many instances of pump failure. Plus, even if the pump should fail, the bike can continue to run (unlike fuel injection systems where such an event means the bike can't run any longer. I always carry a siphon and if required I suppose it could be effective in moving fuel. For those who want to use the Schwarzenegger maneuver, one can simply tip the bike over on its side.

I love the idea of modding the tank with an electric pump. That is just so KLR!

As far as long distances without fuel. You're probably right, although there are plenty of places where gas is hard to find. Riding in Eastern Oregon and Nevada as well as parts of New Mexico makes one aware of how scarce the lifeblood can become, especially when that gas station in the middle of nowhere is closed either due to lack of product (increasingly common) or for some other random reason. (It's happened to me more than once)

Also, last year I was planning a ride through Oregon, Idaho, and Wyoming and found that I had to plan around the available fuel stops rather than what I wanted to see. The supertanker helps with that.
 

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For those who want to use the Schwarzenegger maneuver, one can simply tip the bike over on its side.
One had best BE a Schwarzenegger, to try this, with a fully-loaded (as in, over-loaded) bike!

I asked Peter why he didn't "simply" lean the bike over for the "secret" reserve; he explained, he'd never get it up, with the gear he had loaded (enough for his 45,000-mile trip), and unloading and re-packing would have been most inconvenient where the bike died.

Here's my 7.35-gallon fuel system:



6.1 gallon main tank; 1.25 gallon Pioneer auxiliary container (Cycleracks rack and luggage.) Note low center-of-gravity of auxiliary fuel! :)
 

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NedQuick -

If you don't run slowly at high engine temperature in really high ambient temps with intense sunlight on the tank, the pump will probably not fail. A lot of the failure reports come from Australia and the American southwest, though not all.

I have to preface this with the statement that this is only a theory of mine based upon my pump, a couple of other pumps I've gotten my gritty mitts on, my limited testing, and that I may be full of shit. There, that ought to keep the lawyers at bay.

I did some testing after my pump failed. What I found was that the pump membrane appears to be made of a material that behaves as if it were thermo-setting plastic. At 150°F the membrane, in the presence of 10 inHg vacuum, it will form to the domed shape of the pump cavity.

It will recover if it is taken out of the pump and heated to a bit higher temperature. Obviously, since it is unlikely you'd be able to heat the membrane in the pump without there being vacuum present, it won't recover in the pump. Once failed, it's kaput.

I was skeptical that the temperature inside the tank could rise that high, but proved that it could if the bike is sitting in ambient temperatures of 100°F with direct sunlight and the engine is at operating temperature. Remember that the tank is in very close proximity to the head and almost completely envelopes it. Running slowly makes it worse, as there is no air flow under the tank except for the hot air coming off the radiator.

I did tests with both black and translucent vessels, thinking that the translucent tank would not be susceptible to the 'black body' heating. It was only a few degrees cooler, and I've heard reports of pump failure in translucent tanks.

The problem with the failure reports is that people chalk the failure up to contamination and are really pleased that IMS will send them a new pump for free (by the way, these pumps are used in ultralights, personal water craft, and snow machines and they never fail except at extreme age with contamination). They never do a post mortem. I got a used pump that was being held as a spare. When I disassembled it the membrane was domed.

The insidious thing about these pump failures is that, unless you regularly run your tank down more than 8 gallons, the pump can fail and you'll never know it. That's is what happened to me, at 70 mph in the fast lane of the 405 freeway in Los Angeles. It just ran out of gas, but there were 7 gallons left in the tank when I went to fill up. I think few people regularly run the things down much more than 5 or 6 gallons.

I've run a lot in Nevada, Utah, and some Wyoming/Montana. Having a range of 450 miles is nice!

I don't have any pictures of the finished job, but here are some in-process photos:




Tom
 

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Discussion Starter #9
Very cool mod you've got going there Tom. I'm a little confused about having so much fuel left in the tank after the failure. My impression was that the gas is fed via gravity to the carb. Isn't the pump in the tank intended to feed fuel to the left side? Also, couldn't you have simply switched to reserve?
 

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NedQuick -

The tank will operate as a gravity tank for the first 7-8 gallons, depending on how much sloshing is going on. I misspoke in the above post; I had used 7 gallons and had 3 remaining. It took 7 gallons when I filled up.

The carburetor is fed from a small well that the petcock sits in. That well holds only a cup or so of gas.

Once you've used up the fuel that is above the well (or, more correctly, above the level of your fuel pipe), your reserve is virtually nada. I have a Raptor petcock, which has a really short main pipe. With a stock petcock, you'd already be on reserve.

There really isn't a reserve on these tanks if everything is working correctly, especially with the Raptor. Ideally, if the pump is working and the issue of the right side running dry didn't exist, you'd go on reserve when the main tank was completely empty and the only fuel left was in the well. As I said, that's a very small amount of fuel.

If the pump malfunctions, it is as if the tank is dry. The only remaining fuel is the reserve in the well. I did flip to reserve, which is the only reason I am here typing this and not dead. That reserve almost got me to the gas station at the end of the next off-ramp, which was fortunately downhill so I could coast into the station. However, I must note that running out of fuel unexpectedly at 70mph in the fast lane of the 405 in heavy Los Angeles traffic will cause yellow stains to your personal garments.

Pictures are worth a thousand words. See MacGyver's cutaway photos here.

Tom
 

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Discussion Starter #11
Thanks for the clarification Tom. Short of making a pump mod, having a spare pump, or at least a rebuild kit on board is a wise move.
 

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The kits are inexpensive and take up the room that three paying cards would use. Removing and overhauling the pump might be a pain, but should only take a half an hour.

Oh, and the 'reserve' with a stock petcock is something like half the damn tank. Not really useful as an indicator you gotta get gas.

Tom
 

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Did IMS consider the cheap and highly effective crossover tube similar to the HD fatbob tanks?

Good thread. We already have one of the largest factory tanks in production and we make 'em even
bigger. My hero, Tim Allen would be proud. LOL My SuperGlide had that setup with the
tubes and it never failed in the 30,000 miles I owned it. I'd do it to the KLR but am way too
afraid to mess it up and end up with drippage.
 

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ExtremelyCheapAndKISSishBassTurd,

The wings are so low that a crossover would run the risk of getting snagged on stuff.

The tank is currently set up such that it would be an easy thing to do and it has been considered, but everyone comes to the conclusion that it is too risky.

Tom
 

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Point taken.

A lil' gas leak on the spark plug probably isn't the best way to ride around. LOL
The fatbobs are above and in front of the engine, not like our shape of tank.
 

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Discussion Starter #16
Not quite sure why so many people (usually ones that don't own the thing) think the thing is going to fail. In reading and researching my conclusion is that failures are quite rare. A simple rebuild kit seems like pretty reasonable insurance.
 

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Not quite sure why so many people (usually ones that don't own the thing) think the thing is going to fail. In reading and researching my conclusion is that failures are quite rare. A simple rebuild kit seems like pretty reasonable insurance.
Hey, and what if the pump fails? Only means, you've got some fuel in there requiring some creativity to use!

Why not . . . collect some clean, smooth stones from a nearby creek, and drop them into the fuel tank? The rocks will displace the gasoline, raising the fuel level to usable heights.

When you get back to a fuel source, invert the tank and shake out all the rocks. Save them in a travel bag, in case the lift pump again becomes disabled.

==================

Peter had no problem with his 10-gallon fuel tank on his 45,000-mile ride through the Americas, except the one time he ran out of gas (on one side) en route to Florida.
 

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Discussion Starter #18
I think I'd just do a huge sustained wheelie and if that didn't work simply launch the bike into an end over end jump. That should take care of the problem.
 

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I think I'd just do a huge sustained wheelie and if that didn't work simply launch the bike into an end over end jump. That should take care of the problem.
Lol, or just do like I did with my WR last weekend, dump it in a high banked sand corner with the wheels at the top. All the gas runs down but it's a bugger to pick up! :)
 

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..........By the way, I'm looking for fellow adventure seekers interested in the trip. (date isn't cast in stone yet, but probably July 2016) Info on the route can be found at graveltravel.ca
I might be interested in the eastern portion form St. John NFL to Baie-Comeau, QC.

I rode up from Houston in 2013 to start the TCAT at its eastern end, but one of the two ferrys from North Sidney, NS had rammed the dock and was out of commission and there was a 10 day wait for passage. I didn't have 10 days to wast, so I rode west about 600 miles to cross the St. Lawerence to Baie-Comeau, QC. and picked up the trail there.

There was a section of the trail from Dolbeau, QC up to Chibougamau where I used 6.35 gallons. Fortunately after filling up in Dolbeau I stopped and topped off at the last place 29 miles outside of Dolbeau or I would have been walking. That was before I got the IMS 10.7 gallon tank.

Another example of a situation where a large tank can save your bacon is this. On the same leg to Chibougamau I was about 4 gallons in distance up an empty deserted dirt forest road when I came to two 20 feet deep washouts in the road within half a mile of each other. In both cases a work around was almost impossible due to the dense woods on both sides of the road and the 20 feet steep sandy drop/climb from the built up road to the stream bed below. On the second one the KLR bogged down about five feet from the top of the soft sandy bank the road was built up on. It took me two hours to drag it that last five feet up the bank. I was lucky. If the situation had been just a little worse, I would have needed four more gallons of gas to back track to civilization.
 
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