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lenny6753 12-22-2012 03:03 PM

Expanded tanks
Can someone give me some ideas on how to reinstall expanded gas tanks?

I took both tanks off to do maintenance on the 990 about a month ago. I drained both tanks and left the tanks open so they could breathe and hopefully not expand. Well now that it is time to put the tanks back on it is a no go. The tanks have apparently expanded and I have like 1.0" to 1.5" between where the bottom tank bolt goes through to screw into the cross brace for the skid plate.

I have tried keeping the top two bolts really lose(like only one or two threads started) to gain some wiggle room but still cannot make them fit. If I force the bottom one into place then the top one will not line up and starts stripping the threads when I try to screw it in. I have had this issue before but never to this degree.

I was hoping that leaving the tank lids partially open and the cooler weather(about 50 degress here in Houston) they would not expand very much. I was wrong. Has anyone found a way to make the tanks shrink or to reliably reinstall them.

I'm sure you have all experienced this but I am becoming fed up with it. I want to do my own maintenance but this is ridiculous. It is seriously making me want to find something else to ride. I don't want to throw all the pieces in the truck along with the bike and drive 75 miles(one way) to have a dealer do it.

Sadlsor 12-22-2012 03:11 PM

That stinks!
Sorry, Lenny, I have no answer - I'll be equally interested in the "solution", as I'll be needing to do a valve check really soon. I've had misalignment issues, to a mild degree, after only a few hours of the tanks off.
And, sad to say, after reading similar posts through the years of 950 ownership, I had thought that emptying the tanks WAS the solution...that's what I was prepared to do. I even bought bigger gas cans to empty them into.
Ummm... :ear

BillyD 12-22-2012 03:41 PM

Cinch it
FWIW, when I take my tanks off (and mine have been on and off more than most), I connect a tie-down between the upper and lower front mounting holes and pull it tight.

Not real tight, but tight enough to keep the front of this wishbone shape tank from spreading while off the bike.

Seems to work reasonably well whether tanks are empty or full. Still need some elbow grease to remount.

Maybe put some gas in the tanks (on the assumption that they are more pliable with gas), hook up some tie-downs and let them sit overnight, tighten again in the morning and, maybe, the tanks will go on more easily that evening.

SierraJeep 12-22-2012 03:58 PM

When I do this, I start with the top mount (and hang the tank on the small post up near to fuse block). Then push the side in and make sure it fits with the bike. When you get to the bottom mount, 16 times out of 4 it will not line up.

Here is the trick. Make sure you fully loosen this part...

By loosen, I mean take the two top two bolts out. I see too often on this forum that folks, in my opinion, mistakenly replace with studs. This top place has to be able to float around. The two clips noted as #2 in this picture have the threaded backing for the bottom two tank bolts. After the tanks are both hanging, move this top plate around until the two top holes align with the threads, but don't start them yet. Now adjust the #2 parts (you can reach up from below or use a screwdriver through the bottom tank mount hole) so that the long tank bolt will match up. Get them started but not tight. Once both lower tank bolts are started, then go back and start the two top plate bolts. Once all four are started then you can go around and tightem them accordingly.

This top plate is designed to float around to help start those threads. If you firmly attach the top plate with the studs, the #2 clips will likely slide around during the tank removal process and they will be trickly to get back into place. They can move over an inch away from where they need to be - and this may be what the OP is seeing with his install.

PS - this is key if you have a Safari tank, too.

catalina38 12-22-2012 04:10 PM

I had mine off recently for about a week and drained the fuel while they were off and had no problems getting them back on. But another time they were off for a day with fuel in them and I had to start the top and rear bolts and use a jack to push up on the bottom corner of the tank to line up the bolt, a bit of a pain but worked out in the end. So now my rules are empty the tanks or they can only be off the bike for a short time with fuel in them. Make sure to get the top and rear bolts in a bit before pushing up on the bottom of the tanks. The threaded insert for the bottom mount has some play in it, reach behind it line it up and pull the threaded fitting towards the bolt with your fingers while pushing and turning the bolt. The smarter not harder theme works well with installing the tanks just like changing tires, if you're trying to force it you're doing it wrong. IMHO.

lenny6753 12-22-2012 07:23 PM

Thanks guys for all your replys. I had to stop for the evening or I was going to blow a fuse. Two hours trying to make it work and no success so I will see what I can do in the morning. I am just frustrated. I like to try and do some of my own maintenance to save a little money here and there and the fact that the dealership is so far away. I'm beginning to think it's not worth it. This is not the first time this has occurred but those times I left fuel in the tanks. This time I thougth this would help. Obviously it did not. This is the most "off" I have seen it. Just makes me wonder why I put up with it. It shouldn't be this difficult.

Head2Wind 12-22-2012 07:39 PM

in situations like this, this is what I have done:

Grind a dull point on the lower/front tank mount bolts, this is KEY to the process of getting things back together....then:

1. install upper front bolt, just 2 threads or so
2. install aft both, again, just a few threads.
3. leave the lower tank mount cross member mount bolts loose
4. put or leave the bike on the center stand
5. clamp the front tire to the deck/floor
6. place a jack under the tank at the bolt/mount point and then jack the tank up into position to get the mount bolt started.

this of course gets even more interesting when wrestling crash bars at the same time.....

advNZer? 12-22-2012 07:46 PM

has anyone tried partially filling the tanks with warm or hot water before installing?

DSM8 12-22-2012 07:51 PM

you can also do things with spacers and elongating the holes in a couple spots on the bike to make the mounting easier.

hard to explain, where are you located, if in LA PM me and I can provide more details and you can see what I did to mine to take care of the issue.

BillyD 12-22-2012 08:10 PM


Originally Posted by lenny6753 (Post 20310948)
...Just makes me wonder why I put up with it. It shouldn't be this difficult.

Working on the 990 requires much patience and one must certainly be in the right frame of mind. It gets much easier when one stops asking why they did it that way?

ciedema 12-22-2012 08:12 PM

I have used studs on the top plate - certainly makes putting crash bars back on much easier. I leave top bolts out and just put the side ones in most of the way, but still loose. I usually find it easy to get my head down underneath the bike and look back up the plate and bolt locating hole. The good thing is that the clips the bolts screw into slide around quite easily so just move them about until they line up.

If you are doing crash bars and don't have the studs fitted leave them loose until you have the bolts that go through the top of the plate in. I actually found the stud mod the best thing I ever did - something I still need to do for my new 990.

All that said I assume the tanks have deformed outwards? If so can you use a longer bolt to pull them in, strap it and then install the correct bolts.

Head2Wind 12-22-2012 08:25 PM


Originally Posted by advNZer? (Post 20311099)
has anyone tried partially filling the tanks with warm or hot water before installing?

it would be really hard to get the water out of the tanks after mounting them to the bike.

Stephen 12-22-2012 09:22 PM

I have a long answer and a short answer.

Short answer:
The tanks have swollen because they have absorbed moisture from the air or ethanol from fuel.
Exposing them to warm dry air will reverse the process and they will return to manufactured size.
It could take a few days; it could take a few weeks.
The OP is in Houston and left the tanks open. They likely absorbed moisture from the air–it is very humid in Houston. He'll need a drying environment, say, the output of a shop-vac. Or a warm attic.
And just so you know, I've been there and done it. You'll need some patience, but all will be well.

Long answer:
KTM LC8 tanks are made of Polyamide 6 (or maybe 6-6, not that it matters much), which is a dense, strong and chemically inert nylon. It is some good stuff, damn fine stuff, except... It absorbs water. It absorbs ethanol. When it does, it gets bigger. A lot bigger. And, interestingly, stronger. A lot stronger. Who knew?

Our tanks are very susceptible to absorption of ethanol from fuel, especially if the fuel is old. Old fuel is found at low-end, brand-X, and low-volume stations. It's also whatj's in your tank if you haven't ridden the bike in a few weeks.

Water gets into the tanks mostly from the air. A partly empty tank is partly full of air. If you live where the relative humidity is routinely high, you're susceptible.

To reduce the risk of a swollen tank:
• Keep it full of gas. Only the bare inside of the tank can absorb water from the air. The paint on the outside is a moisture barrier.
• Use a fuel stabilizer to keep the ethanol in the gas. I use Startron, but there are plenty of others that will work. They're all expensive and they all smell funny.
• Tanks off the bike should be ventilated with drying air and then sealed.

How do I know all this?

Good luck, mis amigos.

gozirra 12-22-2012 09:33 PM

I have been facing this issue with my ducati multistrada, without getting too much anger on this post, a solution I found for shrinking the tank back to size is the water absorbing pouches you can find at a home store. I pulled a medium size pack and roped around it in both directions, hung it in the tank, closed the tank cap to hold the bag, and placed it in a warmer setting for a week. Pulled the bag out of the tank and it had some water in it, and the tank had shrunk back to a smaller size.

Not a guarantee but worth a try if you are at wits end. I may have to try this on the ktm tanks soon.

ciedema 12-22-2012 10:24 PM


Originally Posted by Stephen (Post 20311544)
Long answer:
KTM LC8 tanks are made of Polyamide 6 (or maybe 6-6, not that it matters much), which is a dense, strong and chemically inert nylon. It is some good stuff, damn fine stuff, except... It absorbs water. It absorbs ethanol. When it does, it gets bigger. A lot bigger. And, interestingly, stronger. A lot stronger. Who knew?

That an awesome bit of information! Great post.

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