Slow Monster rebuild

[350TSS]

I knocked this up yesterday out of 6mm aluminium plate to support the CF instrument surround and to provide a top mounting point for the fly-screen. This will be attached to the underside of the top yoke via the current instrument mounting bolt holes.
The rear view CCTV screen and the speedo/rev counter will sit in a CF surround which will be packed with foam rubber. I intend to provide a perspex or ABS lens/cover which will hold them in and provide weather protection for them. The lens will be held down by 7 x 5mm ss button head socket cap screws which will screw into tapped holes in the 6mm plate. There will be a rubber gasket between the lens and the CF surround.
I will bond in a CF diaphragm into the fly-screen (a dashboard) that will stiffen the structure and pick up on the 3 “ears” at the top. I suspect that I will need some struts between the current instrument mounting bolt holes on the top of the top yoke to the two outer “ears” to triangulate the mounting.


Today, using the last of my 6mm plate, I made the inner tank circular plate which is effectively 5 captive nuts and will be bonded into the inside of the tank top to secure the filler cap and the filler neck to the CF recess (also bonded to inside of the tank top).

[350TSS]

Productive day yesterday, I managed to cut, bend and drill some 3mm clear acrylic sheet to form the lens for the instrument surround. The material is a swine to cut, the recommended way is to score one side with a Stanley knife then place over a block and crack it, but a) this does not really work for curved surfaces unless you have an exact facsimile of the shape you want to cut and b) it does not stop it cracking in whatever direction it feels like cracking. I tried my jigsaw with the finest of blades and managed to shatter two patterns, a fine toothed hacksaw was also tried which was very laborious and also cracked. The Dremel with a 40mm diamond disc got the job done finally, finished with a fine file.
Bending the acrylic sheet was accomplished with the aid of a vice, two blocks of wood and 15 seconds with a hot air gun. Drilling required a new sharp 6mm drill and very light pressure and even then I managed one 1mm crack when the sheet rode up the drill as I broke through (fortunately small enough to be within the radius of the button head screw). In the picture the protective film that the material is supplied with is still attached.
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Next I turned my attention to the tank mould dividers, a job I have been avoiding as a) I was not sure how best to do it and b) I knew it would be difficult.
The tank pattern is heavy (maybe 15kg) but the top surface is actually quite delicate as the body filler thickness over the foam in some places is less than a millimetre. I will therefore make the dividers for the top surface first to protect that thin skin. The tank will have to be made principally as a top surface and a bottom surface and then bonded together, however, at the front near the ignition switch and at the rear near the seat bridge the shape of the pattern would mean that the pattern would not release from the mould so additional dividers are required.
As far as possible I want to limit the extent that the inevitable “flash” lines ruin the aesthetic of the finished product and over the past months I have mentally changed the proposed position of the dividers about 6 times. Yesterday, I decided that prevarication had to stop and for better or worse their position had to be fixed.
I am hoping that the tank underside can be made in one piece (not yet proven) and I want to ensure that where the tank top meets the tank bottom that I have a slightly conical junction line about 6 to 10mm deep so that a good bonding surface between top and bottom is facilitated. To best achieve this and not end up with a very messy junction line I think I need the bottom edge of the tank top to be extended downward with a slight opening taper, thus the tank bottom mould will have a similarly conical mating surface to the top mould. (I hope this makes sense).
Here are today's efforts

[350TSS]

Made these up today, which are to be bonded into the inside of the headlamp shell, basically fancy captive nuts.
Annoyingly, I discovered that the two places inside the headlamp shell where they are due to be bonded are not parallel (by about 4mm). It was then that I remembered when I was making the pattern I just filed the foam by eye fully intending to square them up later and then got distracted and forgot all about it. The mould is in final form and cannot be modified now so I will have to make a jig to hold them parallel inside the shell and fill the correctional void with resin and CF. (2 bits of 8mm studding joined by a hexagon bar internally threaded and 4 lock nuts).
I think I can massage the mistake on the outside of the shell with two appropriately filed alloy spacers.

The tank mould dividers are now all made up. The skirts I made in 1mm polypropylene. At first, I tried to make the skirts in one piece but the number of angles and curves made filing them to shape a nightmare and I resorted to cutting it into sections, each section containing only one curve or one change of angle. The main dividers are in 3mm polypropylene.
I have decided to not bother with the fuel level warning light sensor in the tank because:
a) space to fit the boss under the tank is constrained and the only available place is very close to the rear cylinder head/cam-box;
b) the standard sensor will need a large diameter boss and that would mean buying large hexagon alloy bar and about £50 for a large tap and die;
c) I have a right angle fuel tap with a reserve position anyway.
I am now pondering ways to include a transparent vertical line into the moulding of the tank top surface that will give me a visual indication of the level of fuel in the tank (as per the 1972 Paul Smart Imola 750SS). This solution really appeals, it is simple and elegant, reduced weight, no maintenance and no failure modes.
Current thinking is to lay down the first gel coat and then put an 8mm bore clear plastic tube (open at both ends) vertically in before the second gel coat is applied and then encapsulate it with the carbon fibre cloth.
Problems I foresee are a) retaining the tube in a vertical position whilst the second gel coat is applied, b) getting the carbon fibre to have a straight edge either side of the tube - a blurry line would look awful although if the tank is painted a straight line could be masked into the exterior paint, c) preventing any excess epoxy contaminating the inside of the tube during the laying up of c 6 layers of CF and d) I will need to treat the tank with ethanol resistant resin after the top and bottom surfaces are bonded together and how can I stop the resin getting into or worse clogging up either the top or bottom of the tube? As I write this I think I have a partial solution to the above – bond in a big loop of tube that is accessible from the filler hole and when tank is finished, top and bottom halves bonded together and ethanol resistant resin has been sloshed around simply cut the tube through the filler neck and tuck the now open top end of the tube around the filler neck and push the open bottom end to the bottom of the tank.

[350TSS]

Too bloody cold to stop long in the garage today, I did manage to drill and tap the rear suspension rocker to take a grease nipple. I am not sure what to do with this whether to polish it up or paint it, polishing would look nice but when fitted it is fairly inaccessible so is likely to be looking a bit crusty fairly quickly.

I also continued with filling and rubbing down the elongated seat pattern which with a couple more fillings and rubbing downs should then be complete and ready for the production of the mould divider.

[utopia]

On the fuel level indicator ....
How useful is a clear sight line on the tank actually going to be ?
You can only really look at it when the bike is stationary.
On anything other than a short run, this will leave you guessing.
You'll probably end up resetting the trip mileometer and going on mileage since filling up.
I tend to do that anyway, even with a fuel gauge.
In my opinion, the sight tube is more trouble than its worth.
Tbh, I would be more inclined to fit a tap with a reserve on it (space permitting .. which it probably doesn't ?).
Or simply not bother and go by the trip.

[mickj]

The other thing I thought is that you have to make sure you cut the bottom of the tube as close to the bottom of the tank as possible, if it curled up at all it would give you a false indication when the fuel dropped below the level of the top of the pipe. Can you reach that far into the tank?

[350TSS]

Good points both Utopia and Mick, I think I will save myself the trouble and use the trip. Thanks

Started today with a bit of rubbing down and filling of the seat pattern and I decided that I would take the opportunity to modify the design a little by raising the leading edge about 25 to 30mm as it interfaces with the tank. This should a) reduce the possibility of gonad/tank contact under heavy braking and b) stop it looking too much like a plank, downsides are it will be more complicated to cut the seat foam and the seat cover will be more difficult to get right.
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Also I had previously tapped out the threads on the instrument panel lugs on the top yoke with the intention of threading in 2 x 65mm studs to retain the instrument panel below and the support bracket for the fly-screen above. I decided that titanium would be best for this threaded stud (130mm threaded). An hour and a half later I had managed a measly 25mm so I gave it up as a bad job and will buy 4 x 30mm titanium socket cap screws and screw them in from top and bottom.
Finally when I was looking for the grease nipple yesterday I came across my 3mm aluminium headlamp support plates which I made ages ago. I was never really satisfied with them as they were heavier than I thought necessary and when I came to lighten them the drill skidded and one of the holes was misaligned. Being on the inside of the bracket, it could barely be seen but I knew it was there and it niggled me. So I knocked up this pattern to make the brackets in CF.

[Darren69]

It would be a neat trick if you could pull it off but as others have said probably of no real use if you have a 2 stage fuel tap. You could always look into the tank and see the actual fuel level.

Didn't Ducati try this on a few of the early 750 Sport or SS bikes using clear fibre glass stripe in the tank and on one of the review bikes there was a dead fly in the clear coat?

[350TSS]

Spent yesterday with more filling and shaping of the seat pattern, the filler is now over 25mm thick at the leading edge. I spent some time pondering how to cover the seat and concluded that I should use, if at all possible, the inside of the seat hump as a tool box/glove box. This obviously involves more complexity and is only feasible if I can get the top of the seat latch mechanism to be no more than 25mm above the rear frame rails. It also requires that the seat hump foam pad is removable. I love planning jobs like this, working out possibilities, analysing constraints and options and whether or not I have the skill to manufacture what I decide is the best option. I now have a plan but I will not know whether is feasible or worth doing until the seat is made and its precise vertical and fore and aft positioning is determined.
When I got bored with this I looked around for a job that would take an hour or so as the garage is too cold to stay in for any length of time. Some while ago I made up a stay to hold the lower end of the headlight bracket. This was made in steel with brazed in threaded plugs, it is quite heavy and not that well made. I found some lighter gauge steel tube and decided that the attachment could be made from CF so I knocked up a mould to manufacture one in CF.

[350TSS]

I started the day by fixing the central and front dividers to the tank pattern having first given it 5 coats of release agent, Oasis foam was glued to the right hand side and the dividers bonded to the foam. It went quite well so I thought I had better quit that job before my luck changed.

I then spent some time modifying the seat pattern, removing the nib between the base and the seat hump. I had to use the Dremel on the wood screws holding it on and I needed some filler to repair the inevitable damage This nib was initially necessary to join the two halves of the pattern together but now gets in the way of providing a useful size opening for the tool/glove box to be located in the seat hump. I think I have worked out how to do it now. When the seat is formed it will have an open bottom and I will then continue the base from underneath to the rear end of the hump by bonding in a shaped sheet of CF (formed on a glass plate), this “diaphragm” will form the floor of the glove box.
The near vertical leading edge of the seat hump will have an ambla covered foam pad glued to a CF backing plate. This backing plate will have 2 x tabs that will fit into slots at the junction between the seat base and the hump (forming a crude hinge) and will be secured by a Dzuz fastener at the apex of the hump. The CF backing to this seat pad will effectively be the lid to the glove box.
To provide some form of positive closure to the glove box I cut some 3mm polypropylene to enable a) the hole for the opening to be recessed by 3mm (this will be sealed with a rubber moulding) and b) an indentation to permit the wire captive part of the Dzuz fastener to be flush with the surface of the seat hump. I also started on a mould for the backing plate for the seat hump pad with a 3mm projection that fits into the recess to be moulded into the seat hump itself.
I also started the laborious process of putting 5 coats of release agent on each of the completed moulds.
I am running out of things to make from CF, 2 remaining possibilities are for the rear number plate hanger and the rear LED stop, tail light/indicator holder currently made in aluminium but quite heavy and a little untidy to look at.

[350TSS]

Today’s efforts,
1. At the top of the picture a pattern for the CF plate which will hold the connectors behind the headlamp (the mark 1 aluminium version is to the right). I have made the pattern with square edges which can be trimmed after the part is moulded, I was never really happy with the cut-away in the aluminium one in any case (the arc was prescribed freehand and then had to be adjusted (made a lot bigger) with a file; and
2. Two of the components which will enable a tool box/glove box in the seat hump, one for glue-ing to the existing seat pattern to de-lineate the tool box opening and the space for the Dzuz fastener and the second to be the pattern for the CF plate that will perform two functions, a backing plate for seat hump foam pad and second a lid for the tool box. I better stop calling it a glove box as I do not think any of my gloves would fit inside. There is a strong possibility that the seat latch mechanism attached to the seat will inhibit further the space inside.

[350TSS]

I only had a few of hours in the garage yesterday and it was hard work. First I filed the two 3mm polypropylene seat hump bits in the picture above so that they were uniform to each other, which involved clamping them together and filing between the clamps, moving the clamps and repeating. It took about an hour.
I think I would rather file 2mm mild steel than polypropylene, you cannot hold it easily in a vice because it marks easily and is too flexible, the material is self-lubricating and the file slides rather than cuts except when you apply too much pressure and “catch an edge” in which case it cuts easily and you end up with an unsightly groove.
No sooner than I had finished getting them to be uniform to each other than I realised that the removable one needed to be smaller in each dimension by the thickness of the ambla covering material otherwise the seat pad would sit proud of the seat hump, that took about another hour.
Then it occurred to me that the lid for the glove box would have to be smaller than the hole it fits in by 2 x the thickness of the CF it would be made of so more filing. The only consolation is that it is a whole lot better to find these things out before I make the CF bits than to discover it after they are formed.
Indoors, I revisited my Estimated Time to Completion (ETTC) and despite adding new jobs over the past week (CF headlamp side plates, headlamp support tube, connector support plate and removable seat hump pad) the ETTC has come down to 244 hours.

[350TSS]

Other life stuff has completely halted progress over the past 4 weeks but now hopefully that is resolved and I can begin a big push to get this bloody project finished.
Today I put the sealing wax around the edges of the tank pattern divider, applied 5 coats of release agent and then laid down the first gel coat on the top surface of the tank.


I also nearly finished filling and rubbing down my re-profiled seat pattern.



I think I have also worked out a way to a) minimise wastage of the carbon fibre cloth when laying it and b) provide the best prospect of an aesthetically pleasing weave pattern in the finished article.
Some of my moulds are quite deep and intricate and my concern was that cutting out a rough shape in the CF cloth and then simply laying it in the mould would lead to creases or worse having to cut the CF after it had been wetted in the epoxy resin.
I am going to cut up some old cotton sheets and use the material to make patterns for the exact shape of the CF that will then hopefully fit into the moulds with least number of creases or strategically placed alleviating cuts. This will take quite a bit of extra time (and probably multiple attempts) as I have never been very good at envisaging the best flat shape that will conform to a multi-faceted concave surface nor have I ever been any good at appreciating how and exactly where to remove material to compensate for corners, etc.

[350TSS]

Good couple of days at the “office” so far this week. The tank mould is now about 30% complete, I started with the top surface and the LH side half came out beautifully, this is the result of about 4 hours work.

The lower part of the divider for the RH side “sprung” a bit and had to be re-positioned to align with the top, this was done with the aid of 2 PK screws, one screwed into the solid side and the other into the “sprung” side. Some string was pressed into use with a lolly stick as the lever for a tourniquet – worked a treat. The RH side is now first coated with gel coat, tomorrow it will get its second gel coat then 24 hours to cure followed by a coupling coat with 100g glass mat and then 4 layers of 300g mat and polyester resin.

The seat pad mould is now finished, subject only to adding some small tabs to the bottom edge that will locate in some slots to be cut in the seat base; it will all be secured with a single Dzuz fastener at the apex of the hump. The other part of the opening for the glove compartment has been glued to the front face of the seat hump; this will have a 3mm recess 3mm bigger in every dimension than the raised part on the seat pad mould. I intend to cut the hole for the opening about 6 mm smaller than the raised part on the pad and edge the CF with U shaped rubber moulding, to act as a water seal and to prevent the CF edge tearing your hands.

Finally I have been looking at the rear suspension rocker sitting on the bench for about a month now trying to decide whether to polish it or paint it and once I had decided to paint it I could not decide whether it should be satin black, silver, red or some other colour. Got off the pot today and rattle can painted it the same colour as the engine, anthracite. It came out well, the can was placed in front of the fan heater for about 5 minutes after shaking and before spraying.
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Finally I have done a preliminary sketch of the colour scheme, red of course with carbon masked off to provide panel edgings.

[Darren69]

Reminds me of the Red/Silver Cropedy Liberator crossed with a bit of Pantah maybe? Which is a good thing imho.