• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

  • Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.

    The Election forum is here: Election Forum

tank dent

L

lsouth3

GEEZER
Regarding manybikes posting about the tank dent.

http://forums.bmwmoa.org/showthread.php?t=48419

It would be interesting to find if pressurizing the tank would push the dent back out.
The tank would need to be empty, dry and off the bike of course with all the openings closed except the one you use to inject the air pressure.
Just a thought. Don't blow anything up! OR you could use water pressure maybe?
 
I have also thought about that method.
However...from what I have read on the net this is a dangerous method with a low success rate.
Apparently you stand a good chance of ballooning your tank out in all the wrong places. The compressed air exerts pressure evenly and has no idea where the dent it, it is more likely to blow out a seam.
This is what I have read anyway.
People who have claimed success say very low pressure, 4-5 psi, is all that is required.
 
Last edited:
Danger Will Robinson Danger - maybe talk to the guys who do paintless dent repair?
 
I have used an over the counter dent repair system that has a plastic handle and hot melt glue. once the glue sets, just pull on the handle where the glue meets the dent and it pulls out. may take a few times, but the repair is invisible. best ten bucks for body work I spent. This worked on a tank and a vehicle. I have not seen them for sale lately though.
 
Hey Infoman

Yes, the kits are still available on ebay etc.
Was it a motorcycle tank you fixed? One of the PDR shops I went to said that motorcycle tanks have metal that is too thick to pull with the glue method, others said it will.

I am taking mine to a shop that feels confident that they will be able to pull the dents, no one will guarantee a perfect fix.
I don't mind getting my GSA dirty but dents really drive me crazy, most people claim they can't readily see mine but I see the damn things everytime I ride it.
 
My r1100r's tank was dented by the PO who dropped it against his r100s in the garage. After weighing the cost of repair and repaint, I found a "bagster" tank cover on ebay, and I'm very pleased with the look.
best regards,
Mark
 
Yes- It was a spare tank that I got on the cheap because of the dent. I figured for the price, it was worth the try. I too, was skeptical. I had no Problem at all. Of course, I am told it depends on how fresh the dent is. I did not even need to have it repainted. Also worked good for a body side panel, I don't even rember where it was excatly after i pulled it out some time ago!

Bob
 
Paintless Repair

Some years ago, I had a crease taken out of a single-wall (important factor) tank for a Honda CB400F. IF the paint "capsule" is not broken, and IF you live in an area that gets a lot of hail (Colorado, etc.) the guys who do this can be VERY skilled. In any light, you could not see any evidence of the crease.

I also personally watched this repair done to a seriously hail-damaged Acura hood, and you could see NO evidence of the damage when the maestro was finished, and I mean, NONE. [Again, this was in Colorado, where they get a lot of practice.]

There is a lot more "art" to doing this well versus "science" -- which I guess is true of any wrenching activity, eh? -- so know with whom you are dealing before going this route - experience counts.

Walking Eagle
'94 R1100RS
'80 Naked Wing w/ Watsonian
 
Having not seen the dent in question this is purely a guess based on logic:

The dent which was caused by negative pressure (vacuum) in the tank probably didn't significantly stretch or kink the metal. And since negative pressure pulled it in I think positive pressure will push it back out. Or the body shop suction cup method?

This is not in the same category as when impact (falling down) dents a tank where usually the metal is significantly distorted and much harder to straighten.

I don't think it would take a lot of pressure. Seal the openings: close the lid, clamp off the vent lines and pump pressure line. Attach a cut-off tire stem to the fuel return line by inserting it into the line and using a hose clamp.

Then take an ordinary bicycle pump and pump a little pressure in there. Not a lot, a little.
 
Not so sure this would work. I tired it once years ago on a Honda fuel tank, and the air pressure actually caused the whole tank to expand and got wider at the "hump".

Before appying air pressure, I would go around the tank in at least three places with those small ratchet straps to keep the tank from expanding. Air pressure, as said earlier, is exactly equal everywhere in the tank, so it will expand all the interior surfaces of the tank.

But maybe with straps around the outside, and a dent puller stuck/glued to the outside of the dent, and air pressure inside, it may pull the dent out.
 
Last edited:
ANDYVH said:
Not so sure this would work. I tired it once years ago on a Honda fuel tank, and the air pressure actually caused the whole tank to expand and got wider at the "hump".

Before appying air pressure, I would go around the tank in at least three places with those small ratchet straps to keep the tan from expanding. Air pressure, as siad earlier, is exactly equal everywhere in the tank, so it will expand all the interior surfaces of the tank.

But maybe with straps around the outside, and a dent puller stuck/glued to the outside of the dent, and air pressure inside, it may pull the dent out.
Click to expand...

Yes but, so was the vacuum equal over the entire internal surface of the tank and that pulled it in at the least strong area. If vacuum pulled it in, and that is all that caused the dent, then + pressure equal to the - pressure that pulled it in ought to push it back out.

I agree it probably won't work for a dent put in by a rock or a knee.

Bicycle pump. Atmosphere + a few p.s.i.
 
Does anyone know it the 04 GSA tank is single or double walled?

I may try and post some photos showing the suction dents. It basically sucked in the tank on each side closest to the seat where the tank curves in.
 
Last edited:
I would think for a double wall tank a dent from negative pressure inside would not appear on the exterior surface.
Mark
 
I would think for a double wall tank a dent from negative pressure inside would not appear on the exterior surface.
Mark

Hmm..never thought about that:blush

Good point!
 
suction cup

I have pulled out dished dents on cars using suction cups. The Glass guys/ windshield repair guys have suction cups you can pump up the pressure of the cup on. I have used suction cups from Habor freight.:thumb

Just a different idea.
 
85K100LT said:
I have pulled out dished dents on cars using suction cups. The Glass guys/ windshield repair guys have suction cups you can pump up the pressure of the cup on. I have used suction cups from Habor freight.:thumb

Just a different idea.
Click to expand...

I did try a suction cup on one of the smaller dents, it was not the type you pump up but it did pull it a little bit. I may try the pump up type. It is very hard to get them to seal.

Just as an aside, I see you live in Cave Creek..what a great place! A couple of years ago I rented an apartment in Scottsdale beside West World (wanted to get some winter riding in), anyway, the odd Sunday I would ride up to Cave Creek to take in the sights at the Hideaway bar..yikes..at the time I think I was the only Ducati rider who ever showed up. I also took in Arizona Bike Week...a very good time.
You have great weather and lots of great roads, I had a very good time, will probably go down there for awhile this winter again.
 
Cave creek AZ

Yes we are just getting into the riding season.

Hideaway is mostly a Harley stop/spot.

Cave Creek coffee company (C4) is an all bikes hang out Duc's (I love the dry clutch)
Many different classics Sunday morning.:thumb
 
85K100LT said:
Hideaway is mostly a Harley stop/spot.
Click to expand...

Yep, I noticed. I will have to try the Coffee Company if I come down this year. Rode a Ducati Multistrada for 6 years. I sold the Duc several months ago and replaced it with an 04 GSA, I also have a 82 R100S (R100 with S fairings etc)
I still miss the outright fun factor the Multistrada had, they are much better bikes than people give them credit for.
 
You must log in or register to reply here.

Similar threads

N
2016 F800GT: acceleration flat spot 4K-5K rpms. Couple of questions...
Replies
1
Views
256
oldcamper
O
pauls1150
Adding Parallel Battery Cables
Replies
7
Views
2K
mikegalbicka
mikegalbicka
88bmwjeff
Winter Project is Done
Replies
7
Views
967
oldnslo
O
1
1964 R69S BMW locking gas cap problem
2
Replies
28
Views
5K
101r69s
1
X
How do I drain the fuel tank in my 1991 K 75 RT ?
Replies
9
Views
2K
pglaves
pglaves
Back
Top