SS90 (copy) bodywork preparation etc

Anything related to paint & bodywork issues on scooters....
Knowledge
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24 Nov 2011
Now the floor.

Working from underneath, I used a 7mm drill to drill out as many spot welds as possible. The rusty floor gave way rather too easily in a few places, leaving excess holes on the tunnel flange. Never mind, these will weld-up.

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A lot of rust fell out of the tunnel, but when the floor was finally off, most of the rust had come from the inside of the floor, which is not an issue at all.

Next, I need to cut the tunnel to allow the frame to be shortened.
Knowledge
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27 Nov 2011

Now I have removed the floor, I have screwed a 600 x 600 sheet of MDF to be bottom of the scooter. I can draw datum lines on the MDF to ensure that I don't go off line.
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I have marked the cut with 40mm wide strip of masking tape. I hope that this will allow me to cut the tunnel. After I finish typing this, I'll be reaching for the hacksaw.

(Actually, I over-sprayed the masking tape with a tin of spray paint, then removed the tape to leave a clear line for the cut)
Knowledge
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28 Nov 2011
I have made the cut. 40mm seems like a lot, but you can see the difference in these before and after photos.

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In the second photo, you can see how the spare wheel fits tight between the seat horn and the bottom of the inside of the steering column (thanks for that measurement Pedro). Compare this with the photo below where the gap at location A is very evident.

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The next task is to re-shape the tunnel and tack it prior to welding by a grown-up.
Knowledge
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28 Nov 2011
Tonight I have altered the cuts to allow the gap at the join to be “eased and adjusted”.

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A series of cuts is required to allow the tunnel aperture to be closed up. Note the small cut on the flange “A”. Note the two brackets screwed to the MDF. These allowed me to ensure that the two side of the cut-tunnel are squeezed-in evenly.

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I tacked the joins together, slid the front end back into place using the box section steel as a guide, and then welded it up.

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I know I am not the best gas welder in the world (in fact, gas isn’t ideal for this type of sheet metalwork), but I have got good penetration and I am sure it will be strong when the floor is welded on.

This might be a good time for you to buy some shares in the P38 body filler company.
Knowledge
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4 Dec 2011
So, back in the shed for an hour this afternoon, and it is time to tackle the rear panel work. Thanks for SteveM, I have a V50 back end, though even Steve will admit that it has seen better days. There are a few problems. One is that some bits of both frames are missing. This means here are no identical reference points to use a datum point. This is a problem, as is the difference between the Spanish frame and the Italian frame. Have a look at the template I cut to compare one of the angles.

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I’m not sure how I am going to address this yet, but I am going to have to push on.

I decided that welding diagonally across the panel would cause too much distortion, and so I chose to cut and join along the top of the panel, as there is a strong curve in the side panel either side of the intended join.

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I made a template for the back of the scooter, using the rear seat mount as a reference point and then reached for the 1mm cutting disc in the angle grinder. Gulp.

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Next, to adjust the joins and tack it together.
Knowledge
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6 Dec 2011
I still have several make-or-break tasks to execute before I discover whether I am wasting my time or not.
Knowledge
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7 Dec 2011
I'm off to the workshop now to light up the welding torch.

If things do not go well, this could be my last post on this thread.....
Knowledge
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8 Dec 2011
Thanks for the kind words of encouragement, but it was not such a good night in the workshop. I could just keep quiet about it, but I’m making mistakes here so you don’t have to. Therefore, I’ve decided to post up a failure.

Thanks started alright. I had a hole in the bottom of the back of the tank area, where rust had got-in around the bracket for the spare wheel (remember, the donor scooter is Spanish). I wanted to repair this before I fitted the new back-end, as access was much better in its present state.

I removed what was left of the bracket and cut a square hole and a corresponding square from some mild steel sheet. I was able to hold this in place quite easily, tack it and complete the weld. Not pretty, but good penetration. I also welded along the entire seam, as this added strength and would keep water out of this seam in future.

So far so good.

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I was aware that I had not cut the join-line correctly, so before I tried to weld the back-end onto the frame, I had to add a small triangle of steel. Before long, I realised that even holding a small triangle of steel on such a complex shape was a real problem. It took about half an hour to cut and shape the triangle, then a further half hour just to work out how to hold it in place prior to welding. Ridiculous.

Once attached, the triangle was trimmed (it is best to make small items of sheet metal too big, so it is left effected by heat during welding) ready for the back end.

The good news is that the centre seam is a common size and location to both Italian and Spanish scooters, so finally I have found a reference point.

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Again, the issue of fitting the two parts together is holding them prior to welding. At first all went well. I made three or four tacks but.....

When I checked the front of the bubble, it was about 4mm out (note yellow paint showing through from under the bubble). Damn.

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It will all have to come off again, but when I try next time, I’ll try to monitor more locations before I start welding.

Nobody said it was going to be easy.
Knowledge
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11 Dec 2011
As you will see, I made my own clamps as I wanted to get on with this project over the weekend and didn't have time to order the pukka items.

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Knowledge
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11 Dec 2011
I released the previous tacks so I could start again. I used the sheet metal clamps to better-align the left panel and got a few tacks in place.

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In the end I was able to get enough tacks in to make me feel this was going to work. Phew. OK, there was still a huge rust hole near the front, but I have a plan (of sorts) for this area too.

I knew all was not well on the right hand side, but I was happy with the left, so I thought this would have to do. However, closer inspection of the right panel showed that some of the curves were not the same with Spanish and Italian frames.

I still don't know if I over-reacted, but I decided to cut the whole right hand side off, and replace it with a remade part I got from Germany. My reasoning was that the RHS panel was badly corroded above the rear light, and I need no compromises around the area of the engine door, which has got to fit well.

I chose to cut the panel much higher (underneath the rear of the seat) as this would help to disguise the weld and stagger the joins on the LHS and the RHS.

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The panel was cut, but the support at the front of the panel was left intact as a reference point. I then cut the new panel to match and trim-up the rear centre seam. I also had to "move" the frame number.

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I ran out of time, but I'm still making progress (and loving doing it)
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