SS90. If I was you, I wouldn't start from here

[allsorts]

Thanks to Soosh, I have a small-frame and log-book. My plan is to build an SS90 copy and fit an existing PK motor into the chassis.

Now have a look at the photo, as see what a task I have ahead of me.

Never mind, I weld and I know a few good people, but I will still need your help.

Has anyone got a back-end available?

Whilst I know you can obtain some new panels (the engine side rear panel is available from WSP and some German shops), I haven't seen the LHS for sale. This might need some careful fabrication.

Lots more questions to ask, but the rear-end shortfall seems a good place to start.

Thanking you in anticipation.

[allsorts]

OK, I've ordered a new engine-side repair panel from Germany (£56 inc postage, which is nice), but if anyone has a panel for the other siode, please let me know. I don't suppose there is a fibre-glass version for sale?

My next thoughts turn to the floor.

I have purchased an SS90 floor from one of the members of this forum and offered this up to the Spanish frame. As expected, the floor is an inch (or so) too short.



OK, so I can cut away the original floor, but if I do not shorten the frame to suit, the spare wheel will not sit right.



Note the gap in front of the wheel on my frame, and that on Mr Collier's original.



Someone must have modified a smallie frame into a shortie frame. Can anyone explain how it is done?

Ta

[ttscshaggy]

The floors sections not to short. The 90SS has a shorter wheelbase
I personally don think making a replica from this frame is a good idea, The spanish super is fairly hard to get hold of as it is and modifying the frame to original spec is going to be really difficult

Ive seen a project where the guy cut a section of the spine out to shorten the frame. That would make me really wary as there is a massive chance of welding the frame back together out of line

[gp200]

i used a spainish frame for a ss90 copy,i looked at taking a bit (25mm) out of the frame but ended up adding it to the tank



i would not cut a frame up ,i think a standard tank does not too bad on the longer frame i only did it as i was making it in to a petrol tank,the spare wheel is not a problem

i welded the ss90 floor on ok ,left a bit on the rear of frame/floor so the brake pedal hole is in the same place

[allsorts]

Thanks GP200. That is an interesting insight into the conversion, and thanks for the photos.

As you can see on my machine, the gap at point A is noticeable.



but point B is correct when I compare it to Mr Collier's machine.

On your machine GP200, does the wheel sit correctly at point A (it appears to) but is there a gap at point B? Looking at your machine, this looks an acceptable compromise.

[gp200]

i have gap at the back (B) but i think i have a 90/80 tyre as the bottom of my tank is flat so i used i smaller tyre ,you could use a bigger tyre to fill the cap

[amazombi]

Cutting the frame and removing an inch means dealing with the fact that the box section tapers out to the front. So when you cut 25mm out the remaining parts will not be identical in width, will they?

Either use a short wheelbase frame, or make the tank longer (which is a brilliant idea by the way) and live with the gap between the wheel and the front, or don't fit that shite at all.

[tony]

For me I would try to shorten the frame seeing as basically that frame is 'not well' anyway

this one is mine.

[amazombi]

Is that a replica? Was that a long frame?

Shortening the long frame has been done, often with less than impressive results, sometimes with a very good result. It is a bit of a pain in the ass though.

[tony]

no its my road bike.. its a real one.. I wanted to show that somehow with the wheel fitting completely into the loop it flows a little better. (sorry gp200- you bike does look ace tho)

[bikegrim]

@gp200 - what coulour is that? i think that is a great looking scoot. well done.

[amazombi]

Nov 9, 2011 22:15:41 GMT tony said:

no its my road bike.. its a real one.. I wanted to show that somehow with the wheel fitting completely into the loop it flows a little better. (sorry gp200- you bike does look ace tho)

I think the biggest Problem is the gap between the tanke and seat. With the longer tank this looks pretty much ok to me. The tire isn't that bad, I'd say. Apparently the look of the original is considered the benchmark and deviations from that are perceived as inferior. At the end of the day it may well be a question of the effort required to shorten it and get it "right".

[tony]

I have seen it done.. not sure the best way tho.. Its getting the tapered section to taper over a shorter distance of course. Unless.... mmm.. maybe at the bottom section of the loop at the front you can cut a vertical section out before the taper really kicks in?

[tony]

on second thoughts and looking at the pic I dont think this will work!

[amazombi]

It wont. You will have to cut open the top of the tunnel and insert, wedge it apart and weld a pointed triangle in, or something like that. A pain the ass. So much so that I'd rather start looking for a short wheelbase frame.

[tony]

I dont think wedging it is the way.. I reckon cutting the section completely out and then making the modification with an added piece before rewelding it all back together. A means of a basic jig is required here.

[ttscshaggy]

getting the frame alignment spot on would be my worry

[tony]

Its possible to do it. Weld up some frame work to bolt onto the tank mounts and get some threaded bar that locates withing the steering column... anybody got a bare 90ss frame to make the jig?

[allsorts]

Thanks for the replies guys.

Amerzombie, I have been searching for a short-wheelbase frame for some time, and I can't find one. I chatted with Sam at TSR in the Far East. He had a ready supply of 50N frames, but these have dried-up. When people do offer him one, they want top dollar and it is barely a viable option for Sam, let alone me.

Vespa prices in Italy and German are mad at the moment. It is close to the tipping point where we will be exporting Vespas back to Italy, whatever Belisconi might have planned.

Since I wrote the post earlier tonight, I have watched the Frozen Planet (no inspiration there, but nice photography) and come up with a plan.

First I find two square sections of box steel, where one slips nicely through the other. Now weld one end on the horn of the seat, and the other onto the inside of the steering column (like a bar for a motorcycle petrol tank), making a slip-joint. The line of this arrangement needs to be parallel to the floor.

Next, remove the old floor panel, sympathetic to the new SS floor pan. Part cut though the tunnel behind the foot-brake and tack-weld the new floor pan in position.

Now cut the tunnel through and slide the front section off the slip-joint box-section. Trim the tunnel at the front and then cut a vertical slit in it so it can be widened (stretched) to match the other section of the tunnel, and then inserting a thin triangle of steel.

Now re-engage the slip joint and use this to line-up the two detached parts of the frame and go for the final welds.

The secret here would be offsetting the two principle welds: the one across the floor, and the one across the tunnel, in order to preserve the strength of the monocoque chassis. The triangle inserted in the front of the tunnel should be hidden in the spare wheel.

I acknowledge that this process has some inherent dangers, but I intend that the frame would be put through the jig to correct any wonkiness even if I didn't do this alteration.

Is this a plan?

[tony]

yep... i think it will work.