Rebuilding 1977 Laverda 1000

R

Rob3CL

New member
Location
Phillip Island
Hi All,
New to this, so hopefully I'm posting in the right place? If not, my apologies in advance. (Also still working out how to post images!!)

I started in March of 2025, the process of rebuilding my 1977 Laverda 1000.

Since then I’ve had the engine top end rebuilt and the frame straightened, wheels trued, new brake discs and brakes refurbished, and a zillion other little bits and pieces!!

So, now it is getting time to consider the body work. First photo below is what the bike looks like now (May 2026).

Laverda 1977 1.jpg
Recently I started work on cleaning the inside of the fuel tank. It wasn’t particularly bad, just needed a bit of a clean out.

Initially I used white vinegar, left in for about 48 hours. Didn’t seem to do much.

Then I tried citric acid, worked a treat! (1 kg of citric acid dissolved in 20 litres of warm water, left for 48 hrs) The inside of the tank, that I could see, was nice and clean. Only problem was that this process revealed a small leak. Of course the leak was in a difficult position. (see photo 'Tank 8')

Tank 8.jpg


Yes, right beneath the top mounting screw for the lovely LAVERDA name badge!!

So, I’ve had to consider options and ‘bite the bullet’ and in the photo above you can see where I’ve partially drilled out the spot welds on this vertical mounting plate.

Once I’d prised this little bracket off, the tank looked like this…(photo 'Tank 7')
Tank 7.jpg
Yeah, not pretty but necessary, and clearly the top ‘little’ hole was a bit more substantial. Isn't it always!!


Now the task is to remake this area of the tank so the rusty bit can be removed. To do this I need to make a couple of metal shapes for a ‘press’ that replicates the badge area of the fuel tank.

Essentially there are 3 presses, with 2 pieces of metal to make each ‘press’. (I hope this makes sense, it did to me!)

Firstly, cut a circle (73mm dia) of 3mm thick aluminium…(refer photo Tank 6)
Tank 6.jpg


So this aluminium circle matches the Laverda badge, as shown in photo Tank 9.
Tank 9.jpg


Tank 5.jpg
Here you can see the 2 pieces of aluminium that make up, what I will call ‘press #1’

Next I need to make the other side of the press. This means I need a 78mm hole on a 3mm thick piece of aluminium. In this photo (Tank 5) I’ve already pressed the 2 pieces of aluminium together in my vice with a piece of 1.25mm piece of steel between.


Next step, gets me to this point. I have the circular indent into a piece of steel, where the LAVERDA badge sits rather nicely, just like on the original tank.
Tank 2.jpg


Now I need to make the vertical indent for the mounting bracket that I took from the tank. To do that I’ve made another pressing tool, shown on the right in the photo below. The darker coloured piece, on the far right, is made out of steel, as I wanted something a bit thicker than the surrounding 3mm aluminium. The steel bit is 5mm thick. This is ‘press #2’, both parts of it are shown below.
Tank 14.jpg


And below you can see all 3 pressing tools together with the nearly finished product in the bottom right of the photo.

Tank 17.jpg

All that remains is for this shaped piece of metal to be bent into the curvature that replicates the area of the tank where this repair needs to be welded into place. I’ll get onto that sometime soon, I need to source a MIG welder for this coming task!
 

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  • Tank 8.jpg
    Tank 8.jpg
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Wow, dedication and clever work. Was it absolutely unavoidable to cut and shut the entire badge section? Would you be able to weld the oblong metal shape over the damaged area and seal it around the perimeter? No chance to braze in and around the holes? And agree with Chris, if the right side is rusted, maybe the left is as well?

BTW, could be camera angle but i think your front guard is on back-to-front? Sometimes it';s the guard and sometimes the whole bracket is in arse-about.
 
Howdy,
Thanks for your thoughts.
I'll have a good look at the other side (inside) once I cut this squarish repair section out. Hopefully I wont need to repair it, however I did make a 2nd repair piece, just in case!!
I did consider brazing, just this requires oxy and oxy puts way too much heat into a pinholed and potentially rusted metal, well the metal tends to evaporate. That is why I (reluctantly) decided I needed to remove and replace the whole section, hence this post.

Interesting about the front guard, I did wonder which way it went. I just marked it when I dismantled everything, and when it came to time to reassemble, I do remember trying it several times in both directions. (Despite my marking as to which way it was when I first dismantled the bike.) Is the back part of the guard, (near the engine) supposed to be a bit longer than the front?
 
51738238740_536d7dc827_c.jpg


Front guard should be as shown above

Interesting challenge with your tank - I'm also interested how this will proceed!
 
Mudguard bracket is arse about... 'guard mounting tabs should face to the rear. Although the OE mudguard blade itself is symmetrical, the "INOX" stamp belongs to the front.

Nice work on the tank repair! Welding without having the entire side of the tank distorting is going to be a proper challenge. There are loads of stresses in the tank pressing that will want to go all over the place once they're hit with a bit of heat!

piet
 
I seem to recall that someone on here successfully inserted a pair of "round badge" panels into a "non-badge" tank.
Possibly in the "Latest Media" photos at the top of the page.
 
I have a round badge tank which someone had converted to the later type (sort of) I inspected the inside with a camera and could see no damage and inspected the round badge shape etc so I assumed it was just full of filler on the outside and the quickest way to remove it was with a bit of heat.
That worked a treat until I reached a flat metal surface underneath which puzzled me ...... until all the lead melted and dripped on the floor.
I thought ok that will clean up and then I saw that it was full of braze as well. What a bloody mess it is now, it had new red paint on it as well ha ha!
I'm not sure if the braze can be removed, maybe someone can tell me.
 
Thanks everyone, front guard now sorted. Tabs rear facing and longer guard section at the back. :)

About the post with the tank badge area inserted into a tank, interesting that the person chose to insert them as circles. Also not sure, but it looks like they perhaps soldered these in place?? Would be a way to not have the surrounding metal warp with too much heat from an oxy torch?
 
When I cleaned my '74's fuel tank, I first used citric acid, and it didn't get the crud out. I love that stuff, but I soon realized it wasn't rust, it was fuel residue. I put in some gasoline and Berryman's B12 Chemtool, and it ate all the crud away, leaving the tank nice and clean. I mix citric acid with sodium bicarbonate to reduce the pH to about 4.0 pH. After the Berryman's I looked inside the tank through the filler hole and with a borescope, and it seems to be coated with something, almost like galvanized or possibly anodized (?) No pattern like galvanized, so I'm stumped what they did, I'm 99.9% sure it's factory original. One of the very few tanks I've treated that surprised me with how easy it was and how clean it came out.
 
gpzkat said:
When I cleaned my '74's fuel tank, I first used citric acid, and it didn't get the crud out. I love that stuff, but I soon realized it wasn't rust, it was fuel residue. I put in some gasoline and Berryman's B12 Chemtool, and it ate all the crud away, leaving the tank nice and clean. I mix citric acid with sodium bicarbonate to reduce the pH to about 4.0 pH. After the Berryman's I looked inside the tank through the filler hole and with a borescope, and it seems to be coated with something, almost like galvanized or possibly anodized (?) No pattern like galvanized, so I'm stumped what they did, I'm 99.9% sure it's factory original. One of the very few tanks I've treated that surprised me with how easy it was and how clean it came out.
Click to expand...

Nope, not factory…. inside a factory tank you can see the welded seam.

If you look with your scope, the seam runs down the centre, the length of the tank. I’ve got one back home that has been opened up from the bottom. I was surprised how tidy the weld is…. almost laser like.

I’m pretty sure you’re looking at a tank liner, Caswell or similar.
 
Rob3CL said:
About the post with the tank badge area inserted into a tank, interesting that the person chose to insert them as circles. Also not sure, but it looks like they perhaps soldered these in place?? Would be a way to not have the surrounding metal warp with too much heat from an oxy torch?
Click to expand...
Laser welding might be another option.
 
The best way to weld thin exhausts is to backfill with Argon Gas and TIG weld. That takes lots of skill.
 
Vince said:
The best way to weld thin exhausts is to backfill with Argon Gas and TIG weld. That takes lots of skill.
Click to expand...

When I was on the tools, I TIG welded stainless pipe hermetically, backfilled with Aron, by the mile, for water, juice, sauce, wine and alcohol.

To reduce the gas used we used a stress balls with a pull through up its arse. Another ball about 300mm from the joint, it was low a density foam ball near the end of the next new joint, low density so the dress gas could pass through, allowing for fresh argon at the joints.

The LD ball had a 6mm airline through it, that supplied the argon. In effect instead of wasting 30mt of argon in a 38mm pipe, we only had to fill about 600mm. Wait for the joint to cool and pull out the ball, and fish out the foam ball. No stress.

Frankly, it wasn’t more difficult than normal TIG welding, but it’s what you get used to.



We had to ear test before welding to ensure there was a gas flow,
 
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