Improving the poor fuel range of a KTM

thommo

IBA Member
#1
Sometime (read this time last year)back I got a message pissing and moaning about the shitty fuel range of a certain KTM by 2 certain KTM owners. Drunkenly, I said I could do something about this without resorting to matches, petrol and marshmellows...
A member of the topbox brigade and sculptural artist mentioned above sent me the following photos of the grand design.







I dug the superior design system out ( stanley knife and cardboard) and after much rum and whisky came up with the real world practical design.







There's no simple 90 or 45 degree angle on this thing whatsoever, just to add complexity for no real reason you know.



A steel prototype was fabbed up and given to the sculptural artist and it was promptly discovered that no two KTM's are alike and character modifcations needed to be made





Design approved, It was time to build the real deal. In aluminium. I've migged 5mm plus ali many years ago, but never tigged it. I'd never used a tig welder in fact. No time like the present to learn, out and brought an el cheapo AC/DC tig welder ( unimig viper 185) and proceeded to create bird shit.



These tanks were basically made in 2 pieces, bottom piece bent up and top piece bent down. Well. mostly. one tank is different as it was bent up on the wrong side of the line, I'm blaming not enough lockdown alcohol which is being consumed at almost a truck load a day.



And then it gots serious. welding, machining, drilling and a tappin'















Access to under the pillion seat in a hurry was a requirement ( battery, fuses, ecu and cruise control boxes etc), so a quick release system has been setup using a base plate that hooks into the seat latch and releases the tank the same was as removing the pillion seat. Dry break connectors for fuel and vent lines to aid tank removal. To give a more secure tank in case of crashing, side rails/tie rails have been added with over centre catches and lynch pins or r clips to make sure the over centre latch can't unlatch...

Video: ( yes it's a link you'll need to click)


https://thomasingrey.smugmug.com/KTM1190-Aux-Fuel-Tank/i-H3J74Mq/A


3 bikes, 3 different paint schemes... ( good thing I'm a spray painter)

















A lot of work for an additional 16Lt...

What's left to do?
make the lanyards for the fuel filler cap and the lynch pins on the overcentre latches.
Fuel line plumbing
Send them to another country as they're allowed to ride and we're not.. ( I live in melbourne, longest lockdown city in the world..)
 

Warchild

IBA Member
IBR Finisher
IBR Staff
#4
I like this. Aside from the filler neck being on the wrong side, this is well-done. :cool: Of course, if you plan on always filling on the centerstand, then filler placement is moot. Only plumbing/venting left to go! With this additional 18L of fuel, what's the bike's range now?
 

EricV

Premier Member
IBR Finisher
#5
@Warchild - stock tank is 23L, (6.1ish), so the extra 16L, (4.2ish), gets you about 300 miles of useable range with ~40 more reserve, all dependent on speed/terrain/wind, etc. 1190s average around 32-36 from what my customers tell me. Some do much better.

@thommo - Nice work and planning. Gave me a good laugh about no two KTMs alike! Having sold aftermarket kit for KTMs, I'm all too familiar with the shite KTM frame jigs and how random any two bikes might be.

The question about fuel spillage referred to the filler neck being on the down hill side when the bike is on the side stand. Common practice is to place the filler neck on the 'up hill' side. Any particular reason you chose the clutch side of the bike for the filler neck?

Where did you located the fuel outlet? Any baffles or sump in the design?
 

Ed.

Premier Member
#8
Yeah, he's done a pretty good job, hasn't he! Not bad for a scruffy Qld bushy! The filler side was a toss up. The choice was made because we all habitually fill on the centre stand.

Plumbing for these is reasonably simple - due to the shape of the main tank there is a balance line across the front. It is a simple matter to T into that and run a (shielded) line back to the aux tank. It will happily gravity feed when the main tank level has dropped a little .

The "no two ktms being the same" is a reference to the fact that the pillion handles on Thommo's (1190S) sit differently to mine and Russ's (1190R).I'm sure a quick inspection of part #'s would have told us that. I solved the problem by clipping the ends off my handles which has the slight added benefit of providing a little more support for the tank.
 

IBA ZX-9R

Active Member
#9
Any consideration given to what might happen to that tank in the event of a collision, where the bike may scrape along the road or impact another vehicle or tumble? I was thinking some sort of plastic casing and/or armor for the edges to reduce or eliminate sparking.
 

Ed.

Premier Member
#10
Lots.
It all sits within the extents of the bike, even more so with panniers(hard or soft) on.
Being made out of alloy, there are much bigger likelihood that all sorts of other (standard/oem) parts of the bike would generate sparks than anything off the tank.
 

EricV

Premier Member
IBR Finisher
#11
The overcentre latches are a wise idea. The OEM seat latch is not intended to secure ~15 kg being tossed up during a collision and they routinely fail to keep even the stock pillion seat in place during a crash. Not sure I like the cast alloy grab bar to secure the latch either, but it's never going to see the IBR, so it only needs to please you gents. Carry on.
 

IBA ZX-9R

Active Member
#12
*thumbsup*

Another way to tackle the range issue would be to analyze the bike's AFR Lambda at steady throttle, basically double check the fuel mapping with a wide-band UEGO sensor. Your bike probably already has two Bosche O2 sensors that the ECU monitors in closed-loop.

I have one of these on each of my street bikes. I use them for tuning, because they cannot be sent to a dyno for that; they're carbureted RAM air bikes. Dyno's cannot duplcate positive airbox pressures, so O2 readings from the bikes at speed is the only way to tune their Lambda readings accurately.

It's hella fun too.
 

Ed.

Premier Member
#13
Exactly our thinking, Eric. The seat latch really only locates it and stops the lateral movement. The over centre latches look after the vertical movement and forces. There is a very small chance we may need an extra attachment, but we have enough space and options that we can do just that at a latter point if needed.

Depending on your perspective, the fact that the pillion handles are not alloy but a solid formed plastic of some sort might increase or decrease your concerns about using them as mounts. From my perspective, I think they are fine. They are very solid, in material, construction and in the direction we are loading them. The material itself is more than hard enough to take a thread tap and a very well tightened screw to hold the catch for the latch, if this proves otherwise later, we can always just bolt straight through. The way they are mounted to the sub frame means they have a small amount of flex when pushing downwards, but they are mounted beneath the rear rack and have zero flex when pulling up like we are doing with the latch. In short, I expect that the latch itself would break before the grab handle did...and if that happened I reckon I will have bigger things to worry about!
 

thommo

IBA Member
#14
I like this. Aside from the filler neck being on the wrong side, this is well-done. :cool: Of course, if you plan on always filling on the centerstand, then filler placement is moot. Only plumbing/venting left to go! With this additional 18L of fuel, what's the bike's range now?
The range will depend on headwinds, how much wheelspin/how hard it is to push through the dirt roads, but we'll get a solid 600 odd km ( 350 odd miles) fully loaded with gear.

Nice work and planning. Gave me a good laugh about no two KTMs alike! Having sold aftermarket kit for KTMs, I'm all too familiar with the shite KTM frame jigs and how random any two bikes might be.

The question about fuel spillage referred to the filler neck being on the down hill side when the bike is on the side stand. Common practice is to place the filler neck on the 'up hill' side. Any particular reason you chose the clutch side of the bike for the filler neck?

Where did you located the fuel outlet? Any baffles or sump in the design?
We found the grab handles are higher and a tad more inwards on the R than my S. Oversight on our part checking part numbers...

I'd normally put the filler on the otherside too, however, Ed and Russ also run camel tanks so wanted to the option to plumb them in, so it was just easier to run the filler on the left side to keep all the fill points on one side of the bike. It's 2 movements to fuel up, fuel the main tank up, move to the rear and fill the other 2 tanks up from the one position. I normally fuel on the sidestand, Russ and Ed fill from the centrestand, so I'll just change my fuelling method slightly to suit.
Once the filler cap is on, the only leakage that could happen when on the sidestand is the one way breather valve failing, it's a non vented main cap with o ring seals etc.
The fuel outlet is on the filler side at the front, no sump as such ( well about 2mm chamfer on the inside of the hole). the base of the tank isn't parallel with the ground, it slopes down to the front and the outlet bung is hard up against the front as I could make it.






There's a vertical baffle centreline of the tank, I did think about adding a horizontal one half way up, but that didn't happen because - i have no idea hahaha

If at half fuel load we think there is a bit to much movement, we'll chuck some foam in there.

I am exceedingly jealous and in awe of the skills employed here. Nice work, really nice work.
Thanks mate, My skills arn't that great, enough to get by I reckon. I wouldn't want to charge by the hour, the tanks would cost more than the bikes!

Great work Thommo.
Thanks TJ, now if only borders and stuff would open, got a couple of years unfinished riding to do!

Any consideration given to what might happen to that tank in the event of a collision, where the bike may scrape along the road or impact another vehicle or tumble? I was thinking some sort of plastic casing and/or armor for the edges to reduce or eliminate sparking.
As Ed has mentioned, there was a lot of thought and discussion about the tank extents. The tank sits inside of the pillion peg pivot point vertically. The crash bars around the tank sits far wider than the pillon pegs and on the right hand side, the exhaust sits outside of the pillon peg pivot line, so aside from a major vehicular impact or impact with a tree that that gets that far in, well, The rider is going to have other major issues to worry about... most other slides down the road etc, the tank won't be impacted at all. I based the outer extents of the tank on my bike, which is narrower than the others, the pannier frames hug the rear bodywork, the exhaust is smaller and narrower than the stock and ackro cans by a consideral amount. We spent a lot of time looking at photos of wrecked 1190's just to see which bit bent and broke the most along with speculating what type of collision caused it.

The overcentre latches are a wise idea. The OEM seat latch is not intended to secure ~15 kg being tossed up during a collision and they routinely fail to keep even the stock pillion seat in place during a crash. Not sure I like the cast alloy grab bar to secure the latch either, but it's never going to see the IBR, so it only needs to please you gents. Carry on.
Oh yeah, we knew the seat latch alone wouldn't be enough, but working out what would work and how to do it was lots of head scratching. In the end, I settled on the rail and over centre catch and hooked to the grab rail, which flexes a little bit, but that flex will be helpful to aovid cracking and other stresses on the tank. I was pleasantly surprised at how solid and hard it was to drill and tap that plastic grab rail.

Perhaps Warchild could weigh in with his expertise on if he would pass it for IBR tech inspection?

the welded on plate to the tank sides is 50x10mm Ali 50mm long drilled and tapped M6, the bolt on rail is 25x6mm Ali 280mm long with 4 M6 bolts, the over centre catch is bolted on with M6 bolts. The tank is bolted onto to the base plate with 4 M8 bolts, there is 50x10mm Ali bar full width of the tank welded on and tapped M8. The tank itself is 3mm Ali.







The base plate is 4mm thick and hooks into the same 3 points as the pillion seat, the latch point is steel round bar, and the rear 2 points are 12mm Ali bar stock, with a round hook end to hook into the rear points. 3mm rubber strips sit between the tank and base plate as a vibration damper.[/USER][/QUOTE]
 

EricV

Premier Member
IBR Finisher
#15
I did not realize the KTM grab rails were plastic. I would perhaps consider a steel bracket mounted at the pannier mount to the rear subframe that came up to a spot where you could attache the overcentre latch hook, instead of using the grab handles. It would likely require a bend or two and a gusset to limit flex.

It will be interesting to see where you locate the valve for the aux tank. And the dance of trying to use the Camel tank, which vents the main tank through it, and the alloy aux tank, which has it's own vent/roll over valve, thus negating the use of the Camel tank when the alloy aux tank is in use.
 

Ed.

Premier Member
#16
Our camel tanks no longer vent the maIn tank, that system doesn't work with the tank wrapped over an angry, angry engine and summer air temps.
Will be a simple matter of managing taps.
 
#17
Ed and many others have had all sorts of dramas trying to make that camel tank vent setup work. Any day over 20 degrees and they simply don't work so well. It's far easier and more effective to run the fuel line down to the front of the tank where the fuel taps and balance pipe is and simply Tee into that. Inline on/off tap where you can reach it.

I've had many chats and agreed to disagree with Robin of Safari tanks who make 2 5Lt plastic rear tanks for the 1190 for close to a grand and they use the same vent setup as the camel tank. You damn near pull the entire bike apart to fit the Safari tanks. Robin and I have had many errrrr spirited discussions over many beers about this and I suspect we will have many more over beers when our paths cross.

On the steel brace from the pannier frame mounts idea, It has crossed my mind and I have an idea that should work if we think the grab handle setup isn't going to cut it. See what happens after a couple of longer rides and tweak things from there I reckon.
 

EricV

Premier Member
IBR Finisher
#18
@thommo - You and I share the same strong opinions on vent line draw setup for aux fuel. And I too have had many a spirited conversation with those that expound on their 'benefits'. I didn't want to mix it up in your thread, so let that dog lie.

I would love to see a picture or two of the valve and cross over line connections when you have the set up finished. I'm sure others would enjoy that as well. I've run gravity feed aux tanks for a long time on different bikes and always prefer the traditional bulkhead fitting to the main tank, but have not owned a KTM. Good on you for sorting another ~160 kms in range.
 

thommo

IBA Member
#20
So with Melbourne lockdowns ended and now able to to travel around the state, Ed and I decided a nice meet in the middle from our joints would be the go, originally going to be a meet at the pub and roll the swag out somewhere and fit his tank up became a day trip for various reasons, so a nice 700km jaunt was the go. Rolled into town only to find the 2 pubs still shut due to covid rules I reckon so no beer or counter lunch.
I knew of a nice little brewery in town which supplied us with some takeaways and down to the local park like bums to setup the field workshop.

Crazy eyed Ed going weak at the knees with orange goodness



Mobile workshop



Two legal Beers later






One more tank to fit up in the next few weeks.