Slow Monster rebuild

[350TSS]

I will obviously drill a hole (circa 20mm) at the lowest point so I do not have a "tank of two halves" with the tap feeding air and 1.5 gallons on the "other side"

[Mr Gazza]

Why have you fitted a fore and aft baffle?
I don't think fuel sloshes from side to side. Or does it? What forces move it sideways?
I sit on my bike and feel no sideways force. Any cornering force is countered by leaning.

I think there are large and more undesirable fore and aft forces when braking and accelerating.

[350TSS]

I am not sure I agree with you - if you consider taking a chicane for example, I think that the input force to make the bike change direction occurs before the bike is subject to the centrifugal (or is it centripetal force) when the bike is in that part of the chicane. I think it unlikely that the fuel level within the tank stays parallel with the bottom of the tank throughout the manoeuvre.
I may be wrong and I may have wasted a day of my life.
In any event 3 x cross ways baffles are planned for the tank top to stop the sloshing forward under braking

[Darren69]

I wouldn't have thought it necessary on a street bike but if it being considered an issue why not use a race style fuel cell and make a dummy tank cover? Would have made the tank fabrication easier too I would think.

[350TSS]

The tank capacity is probably between 4 and 5 gallons and is quite narrow (no wider than +5mm on the frame rails) and about 30mm taller than a standard Monster tank so some sort of baffling is desirable, particularly fore and aft.
I researched fuel cells but they are expensive (>£300), also the foam blocks you can insert through the filler cap (at least £120) with no guarantee that I would be able to get the foam blocks to locate to the back of the tank satisfactorily.
My tank baffles whether strictly necessary or not will cost virtually nothing other than time as I have made the CF sheet already. So I might as well make them

As to a tank cover I am way too far down the line to contemplate that and in any case it would just be additional weight.

I have come to the conclusion that attempting to put the transverse baffles in the tank top and introducing over the fore and aft baffle bonded to the tank bottom will not fly so today I started cutting up the remains of the CF sheet I made to make 3 baffles. Dropping the Dremel and bending the arbor for the cutting disc stopped play prematurely.

[350TSS]

Today I cut my cross ways baffles and after positioning them with duct tape on one side I CF’d them into place. Tomorrow when the first side has cured the other side will also be CF’d.
Next I moved onto the tank top. After almost a success with the seat base I was hoping that I had cracked this CF malarkey.
The first dent to my over confidence came after I had mixed up the epoxy (260ml) and applied it to the gel coat already in the mould. In about 3 or 4 places it crinkled the gel coat, which means that these places will end up having to be filled from the outside.
I cut my cotton pattern some while ago and went to cut the CF which I intended to use as the first lamination, which I was hoping I could lay down in one sheet with just a few minor cuts to accommodate the shape of the mould. The remnant on my roll was not quite big enough so I broke out my second roll and the CF, whilst the same grade, weight and weave as the original roll, was considerably stiffer than the first roll material. It was as though it had been starched. Within about 20 minutes it became clear that there was no way this second batch was not going to be laid down in one lamination with minor adjusting cuts. In the end I had to put it down in seven overlapping sections.
Because of the overlapping I needed more resin than I mixed so the last panel went in with the last dregs of resin on the brush rather than being saturated then rolled and squeezed with a scraper with the surplus being recovered for use elsewhere. I read somewhere it is not a good idea to mix two batches of resin mix in one lamination, so there was a lot of begging Peter to pay Paul.
The next problem was that the tank top mould when inverted is about 400mm deep with near vertical sides and the epoxy resin, which is very thin has not the adhesive strength to hold the CF at the top of the mould, gravity overcomes the adhesion and the CF separates from the top of the mould and starts to migrate towards the centre bottom of the mould.
After a good hour of buggering about I had all the CF wet, all the sides right up to the top attached and everything hunky dory so I retired for a well-earned cuppa. I deliberately used slow cure hardener when I discovered that the second batch of CF was nowhere near as pliable as the first. It will take at least 24 hours to go off fully as mixed.
I came back about an hour later and the sides had separated from the mould and worse there were bubbles on both sides at the transition between the very top of the tank and the sides. It is very clear that in wet laying CF the CF mat moves as the resin cures, it tends to move to its woven flat state pulling it away from the desired/required mould shape. The proper way to make CF is with resin pre-impregnated mat with a vacuum bag drawing the catalyst through the resin whilst the mat is held tight against the mould by the vacuum bag. The resin with the CF anchored in the right place cures in the bag either with assistance of an oven or over an appropriate time.
I spent another hour or so with the roller trying to stretch the CF mat within the setting resin and re- securing the sides to the mould. I have a feeling this will not end well, I have no intention of staying up all night prodding the increasingly resistant resin into places the CF mat does not want it to sit.
My real concern is that I decided on a CF tank for lightness, at each step in the manufacture the weight has gone up. Were 3 laminations sufficient for the base? The easy decision to take was to add another 2. The base is now extraordinarily stiff, as stiff as if it was pressed out of 2mm steel.
Fixing my faux pas with filler is kind of essential cosmetically but does nothing for the overall objective. A lot of filler has been included, a lot has been rubbed off. I guess it will be next week before I find out if I have saved the planned 3kg, what do I do if it is only 1kg - start again?

[350TSS]

Productive day today, I finished the baffles on the tank bottom, they may need a bit of trimming when I introduce the tank top over them.
The tank top got a second lamination of CF, I think I will give it just one more and then hope it is strong enough.



The seat had its glove box aperture cut out and then had 3 filling and rub down cycles, I think maybe 2 more before it is ready for primer.
I also re-made the mould for the glove box lid which will also be the bum stop on the seat. I included two tabs on the mould which will locate in two slots on the seat base with the lid/bum stop being retained by a single Dzus fastener at the apex of the hump.
I think I also know how to get the wiring loom through the RH infill panel and round the headstock. The inside needs to be smooth to permit the loom to move as the steering is turned and therefore carbon fibre will not work here. I first tried making a 40mm OD tube about 50mm long out of some 1mm polypropylene bonded together with Q Bond. But even at the most extreme angle I could manage it was pointing in the wrong direction. I will tomorrow try to panel beat some 1mm aluminium into a tube with a curved entry through the infill panel. Play got stopped by not being able to find my panel beating set, which I have obviously put somewhere safe

[350TSS]

Not a good day today, I managed a very passable attempt at forming a 40mm OD tube from 1mm aluminium sheet which took about an hour but failed to successfully panel beat the tube to have a 60 degree bend in it which took about 2 hours before I gave it best.
Next I spent about an hour trying to get the tank top out of the mould, one half came out and my 13 year old son would describe it as an “epic fail”. I was almost expecting it but it was nevertheless disappointing. It is beyond repairing and in any case it is one thing to have a little bit of de-lamination and filler in a hugger but with a petrol tank de-lamination will lead to leaks so it has to be near perfect .
Worse on the half of the mould exposed it is clear that before I can re-make the tank top I will have to do quite a lot of removal of epoxy resin that has not released properly and has stuck to the mould. I struggled for another hour to get the second half out of the mould but my heart was not really in it and in the end I retired hurt and dejected. I think I will have added about another 10 hours to the ETTC to make good the mould and re-make the tank top not to mention about £40 worth of resin and CF.

[350TSS]

I spent about an hour yesterday finally managing to get the LH side of the tank top out of the mould. Oddly this LH side whilst not perfect was easily repairable, nevertheless with the RH side so poor a second attempt will have to be made.

I have a few theories why this one went so wrong, but in all probability it was a combination of factors: a) not getting 100% coverage of the mould with the gel coat, brush striations allowing the epoxy resin to be laid down directly on the mould, b) leaving too long between putting down the gel coat and the epoxy resin, it is supposed to be still very slightly tacky when the epoxy is applied so that you get really good adhesion, c) using the stiffer CF mat which would not conform exactly to the mould shape allowing air pockets between the gel coat and the mat.
Today shall be spent cleaning up the mould ready for another go. First job is to scrape off with a blunt screwdriver where the epoxy has gone through the gel coat and adhered directly to the mould. It took about an hour yesterday to not quite complete the less afflicted LH mould. Second I will have to fill and rub down the half dozen or so chisel marks inflicted on the mould when trying to separate the mould from the component. This will be followed by a polish with 2000 and 4000 grade pads and finally 5 coats of release agent.

[350TSS]

Epic tank fail

[350TSS]

Repairing the tank top mould and getting it ready for the gel coat took nearly 2 days, I managed to get the seat base into primer which, after a light rub down with 600 wet and dry, clearly needs another round of filling to get rid of all the pin holes.
To encourage myself I decided to trim the failed tank top so that I could start to think about seat positioning. Here it is mocked up with the seat front first pass trimmed.
gypsy baby girl names


With the seat in this position I am sure there is enough room for my legs, and enough room to stretch fore and aft. After the addition of foam the seat base will be about 20mm higher than a standard M900 seat. Because of where the rear seat latch will fit inside the hump the cubby hole in the seat hump will probably only be big enough for a couple of spark plugs and maybe 2 bungees, definitely not winter gloves. C’est la vie.

[350TSS]

Re the above I do not understand why R =1.414 - what is the origin of the equation? why is it the square root of 2 x weight?

Today’s efforts, two laminations on the tank top, which, fingers crossed, seem to go OK. I will find out today when I remove it from the mould.
The seat hump pad also got 3 laminations.
Next I turned my attention to making a “guide” for the wiring loom to pass through the infill panel and around the headstock. Forming a 37mm diameter tube from 1mm aluminium went surprisingly well but panel beating a 60 degree curve in it was beyond me. I decided therefore to make it by aluminium “welding”. It took nearly all day and 4 attempts to get the shape I wanted. The first two were just not the right shape and /or the exit port pointed in the wrong direction, the third I managed to burn a hole whilst trying to weld it and the fourth I was reasonably happy with.
Before bonding the tube to the CF infill panel I thought I had better offer it up to make absolutely sure the angle was right and then it dawned on me that with the two parts bonded together there would be insufficient clearance for the completed part to be inserted into place. Complete waste of half a day and back to the drawing board but with no real clue as to how to actually achieve the objective.

ETTC is now down to 216 hours. The biggest challenges going forward are:
1) Bonding the top and bottom tank halves together successfully
2) Resolving the seat mounting/height/fore and aft positioning
3) Brake pipe/clutch pipe/throttle cable routing
4) Setting up the Hall effect ignition
5) Overhauling the cylinder heads (lapping the valves, new valve guide seals, valve shim collets) and setting valve clearances

[Darkness]

You can use that same triangle of forces to consider a wall of death.
In that case the weight of the bike is vertically downward, but the cornering force is horizontal. The other force which stops the bike from dropping is friction, and that would be about 0.2 of the cornering force due to friction (Miu).

[350TSS]

I spent a long time today getting the tank top out of its mould. The LH side took about an hour but the RH side took, 6 chisels, 6 screwdrivers and 3 tyre levers and about 4 hours to separate it. The component itself is OK, certainly repairable with one side a lot better than the other which had some collateral chisel damage.


Over the previous couple of days I have put down a couple of laminations on the fly screen and also a CF sheet to be used for the dash board which will be bonded into the fly screen and bolted to the instruments. Each of the tank top, the CF sheet and the fly screen got another lamination today, running out of epoxy resin stopped further progress.

Unable to make further progress with the CF tasks I gave the seat what I thought would be its last rub down and a further coat of primer. In primer it is obvious that another rub down will be necessary.
I thought I would trial fit the hugger to the swinging arm, just a matter of drilling 5 x 6.5mm holes I thought. Oh no not at all. The original M900 hugger was made of a fairly flexible plastic and I used the old hugger to make the mould for my CF one. What I did not realise was that when removed from the swinging arm the perfectly flexible plastic relaxes. I made a pretty good copy of the hugger in its relaxed state. CF, whilst flexible, is amazingly rigid, the lugs on each side of the swinging arm were 25mm inboard of my CF hugger. That made finding the right place to drill the 4 holes a bit of a challenge. I eventually managed it although one side sits about 5mm higher than the other which I will have to rectify before it gets finally painted.

[350TSS]

Back to stuff I almost understand.
I took my CF sheet off the glass this morning which came out OK, just a couple of minor imperfections. I realised that 3 laminates will not be stiff enough to support the fly screen so another lamination was laid down.
Another lamination was also applied to the seat hump pad which when cured should be ready for cutting to shape. The pad and the seat will then have to be tailored to fit each other so a) the outside edge of the pad follows the same external contour as the seat hump, b) the raised part in the middle of the pad fits into the glove box hole and c) the slot is cut in the seat base to allow the pad to locate without compromising a) or b) above. The slot will have to be cut first.
Then I had a 3 hour struggle getting the fly screen out of its mould. The outer surface has about 3 places where repair will be necessary but worse the stiffer CF has not followed the mould very well so I shall have to grind out where it is not in contact with the outer skin and lay down a couple of fresh laminations. Once that is done I will have to fit the headlamp to the front fork yokes and then ascertain where to cut the hole in the front. This will be tricky because the headlamp bezel is due to protrude through the fly screen at the top but not at the bottom so the hole will be slightly elliptical and getting the height and the shape of the hole right could be problematic.
My ETTC is now down to 190 hours
Pictures will not upload today sorry