Slow Monster rebuild

[Mr Gazza]

I'm a bit surprised at your thoughts about a higher rate of return.
The volume of fuel can only go down once the cap is closed.(assuming a constant temperature.) There's nowhere for any extra fuel to come from.

The tank, along with the pump and fuel rail are full of fuel.
The pump pressurises the fuel rail (a very low positive pressure), and pumps fuel round it, back into the tank. Fuel exits via the injectors at a variable rate, but there is always an over supply and fuel constantly returns to the tank whether needed or not.

In order to return more than it has taken from the tank in the first place, it would have to draw from some other supply.... It's a loop. It just sucks in one end and squirts out the other with a bit lost in the middle on demand.

I have Capo's article on fuel caps, with pictures. But I have tried without success to post it before.. Sorry.

[Darkness]

Originally Posted by Mr Gazza

I'm a bit surprised at your thoughts about a higher rate of return.
The volume of fuel can only go down once the cap is closed.(assuming a constant temperature.) There's nowhere for any extra fuel to come from.

The tank, along with the pump and fuel rail are full of fuel.
The pump pressurises the fuel rail (a very low positive pressure), and pumps fuel round it, back into the tank. Fuel exits via the injectors at a variable rate, but there is always an over supply and fuel constantly returns to the tank whether needed or not.

In order to return more than it has taken from the tank in the first place, it would have to draw from some other supply.... It's a loop. It just sucks in one end and squirts out the other with a bit lost in the middle on demand.

I have Capo's article on fuel caps, with pictures. But I have tried without success to post it before.. Sorry.

Yes, that’s my take on it too.

The only reason for petrol to come try to get out of the tank through the breather are if it’s got seriously hot since the tank cap was filled, or you are standing the bike on its front wheel braking, so all of the fuel rushes to the front of the tank.

[utopia]

Yes, it was a bit of a half-hearted pondering, tbh.
My feeble excuse is that I was concentrating on valve clearance adjustment at the time.

I'll get my coat.

[350TSS]

I thought I would start the day by quickly removing the seat mould from the pattern and then tidy up the edges of the mould, removing all those sharp errant resin coated strands that have an amazing ability to penetrate skin. Two hours later I was still at it. It was not for lack of trying or wood chisels.

I think my worst fear has been recognised, I always knew there was a risk of mould locking if I divided the mould laterally rather than longitudinally and it seems that risk has crystallised – BUGGER!!!!!!
Frustrated and not making any progress I set the seat base aside to come at it afresh tomorrow. Nothing will change overnight except perhaps my demeanour. I therefore decided to concentrate on:
Cunning plan 1 – this is to provide a gasket face on the inside of the tank top mould that will locate the tank bottom mould and give something to bond (and seal) the two halves of the tank.
The plan is to mould from 25mm wide CF tape a “ring” that follows precisely the lowest edge of the tank top that will drop about 3 to 5mm into the tank top CF mould and be bonded into position. It will, before the bottom half CF mould is introduced, be overlaid with 2 possibly 3 layers of CF from the inside to provide a rigid reinforcement for the lowest edge of the tank.
I don’t know that it will work but it is the best plan I can come up with.
The first step of the process is to apply 5 coats of release agent to the bottom of the mould then mask off the tank bottom mould where the gasket ring is to be formed. No gel coat will be used, just epoxy resin and probably 2 layers of 25mm CF tape. Below is a picture of the tank edge masked – this delineates where the epoxy resin and the CF tape will be placed, I have ordered some special masking tape to be put either side of this ordinary paper masking tape which will be removed when the special tape is laid down either side of it.
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and
Cunning plan 2 – this is to facilitate the provision of a clear strip that will act as an external visual fuel gauge.
It involved splitting a 20mm plastic electrical conduit tube longitudinally and at either end cutting a 20mm deep slot in the ½ tube wall. The tank top mould will be coated with clear epoxy compatible gel coat and when the final location of the gauge is determined (positioned vertically from the lowest edge of the tank top mould) a 25mm wide section will be masked off. Ethanol resistant resin will be applied to this 25 mm wide strip and when it is ¾ cured the tube will be bonded to the tank flank with more ethanol resistant resin. The whole of the inside of the tank mould will then have x number of laminations of CF and epoxy resin overlaid, taking care not to seal the at either end of the tube. The whole of the tank top and the, still separate, tank bottom mould will then have a coat of ethanol resistant resin. When this has cured the two halves of the tank will be bonded together and more ethanol resistant resin will be poured inside and run around the seams to thoroughly coat them. Here is a picture of the sight tube, split in half with cut-outs top and bottom, I may put some painted graduation lines on the inside of the tube (or drill holes at regular intervals) but that might be an embellishment too far.

[350TSS]

Finally I tackled a job I have been putting off, drilling the two mounting holes for the case saver that locate onto the alternator cover. I had to jury rig the cover and then use my best guess as to where the holes would locate as the case saver has to be pushed into position so as to get sufficient clearance on the drive chain. Made from 2mm stainless steel it is quite springy and alone I do not have enough hands to force it into position, align the lugs and mark them out. An added complication is that the case saver fits outside the alternator cover so the lugs mask the holes. It simply was not possible to fit the case saver inside the case and mark the lugs through the case as these holes are blind (used to attach the sprocket cover) I made my best guess and I drilled at 6mm and it would not fit. I took it out to 6.5mm and it fitted nicely – result and another job off the list.

[mickj]

Engine looks fantastic.

[Mr Gazza]

Regarding your release problems; you could try getting some water between the mould and moulding.. Get a hose in there if you can.
It will help soften the release agent and the weight of it will help push them apart.

They used to crack off a bit of the top of a boat hull moulding (up to 80' boats!) and push a hosepipe in there, running for an hour or so. If you were lucky, after a while the buoyancy of the moulding would overcome the stiction with a crackle and the moulding would be floating an inch or two out of the mould.

The ye har method was to lift the moulding via temporary bonded in eyes, with a giant crane. it would be hung a foot or so from the ground and jerked a few times. (Very scary as the crane wobbled on it's jacks!)
Release was heralded by a mighty crack and often a brilliant flash, even visible in daylight, as the static charge dissipated, then a thump as the mould hit the ground.
Killjoys could avert the static flash by laying a chain over the mould's metal framework to contact the ground, but a sort of sensible approach really, if the releasing is done inside with all that styrene and acetone about.

You could also try beating your moulding about a bit with a rubber mallet. An excellent way to decorate your moulding with ornate star crazing...

[350TSS]

Thanks Mr Gazza – alas I saw your post too late as I have achieved this:


Bad news
a) It took 5 hours
b) I haven’t finished yet as I need to spend at least an hour repairing the mould where there was a chisel /mould interaction
c) The garage is absolutely covered in a million tiny pieces of the pattern which had to be completely destroyed to get the mould off it and this will take a further hour at least to clean up.
Good news
a) I am almost certain that mechanical locking was not the reason that the mould was so difficult to remove, which means that I can use it for the carbon fibre seat without modification. I will however remove the CF seat from the mould after a gel coat and one layer of CF whilst there is the possibility that it is flexible enough to spring out.
I am pretty sure that the reason it was such a bugger was that I applied the release agent and the gel coat directly to rubbed down filler. Normally I would have coated these with pattern primer and high gloss resin and then polished them but since the filler bit was to be under the seat foam and the upholstery I was not that bothered about the finish. I think that the filler whilst smooth is porous and the release agent escaped into the pores with the result that the gel coat bonded perfectly to the filler. A lesson hard learned.

[350TSS]

I spent a couple of hours today progressing with the tank “gasket”. I got about an hour in and I think I realised that this was unlikely to work. The epoxy resin is quite thin, say 40W oil viscosity and not that sticky. The CF tape is very malleable/flexible until you put the resin into it when it becomes much less so.
In any event I laid down one layer of CF tape and left it to cure ( I used slow curing hardener to give me the most time to manipulate it). I came back 3 hours later and the CF tape had sprung away from the tank bottom and the a good percentage of the epoxy was lying in ¾ hardened puddles in the low point in the tank base.
Nothing to do now but wait for it to harden fully then try and remove it, I just hope the release agent has worked this time.

[350TSS]

Yesterday I separated the “gasket” from the tank bottom pattern, unfortunately a) it came away in 3 pieces and b) it mostly separated between the resin and the carbon fibre tape and not between the release agent and the resin; this resulted in a corrugated surface mirroring the weave of the CF tape which was extremely well adhered to the pattern. It took a determined couple of hours with a screwdriver to remove this.
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The gasket being in 3 bits is a problem because if it is ever to replicate the tank bottom profile then I will have to put them back in situ on the pattern and re-epoxy with a second coat layer of CF tape. Rather than relying on release agent, I will, this time, put a layer of the special release tape down on the pattern. I have little confidence that even with an integral and one piece “gasket” that this approach will actually work. Like others at the moment I do not have a plan B so I must just press on and hope for the best. I have a number of concerns, the first is holding the gasket inside the CF tank top at about 4 to 5mm below the lowest edge of the tank while it is bonding and second, when it is bonded in, how to apply sufficient resin to take up the gaps and keep it in situ while it cures when the bottom of the tank is introduced to be bonded and hopefully sealed into place. The standard CF epoxy resin has a viscosity of about 40W oil and I need something with the viscosity of silicone bath sealer for both applications, even araldite would be too runny.
The seat mould is now trimmed down using a Dremel and cutting disc, the seat base surface is repaired and rubbed down and ready for release agent.

[350TSS]

Well the “gasket“eventually came out in one piece, I really think I am flogging a dead horse with this (how will I hold it in place to bond it to the tank top? how well will the very corrugated finish on the gasket provide a seal to the tank bottom? how will I hope to retain sufficient resin on the mating surface to seal the top of the tank to the bottom? etc., etc.,) but I simply cannot think of any other solution.
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With the “gasket” removed and the extraneous resin chipped off with a screwdriver, I re- waxed all the edges and re-release agented the tank bottom. Then first gel coat is now on, although I am slightly nervous that my scraping with a screwdriver to remove the extraneous resin will cause the release of the mould from the pattern to be compromised. I am definitely getting to the stage now where the finish on the bottom of the tank is not worth the extra hours required to fill and rub down slight blemishes that will not show.



I thought I had better knock up a threaded boss to fit the petrol tap to, but on closer examination the gland nut on the tap I have is left hand thread 16mm and nowhere on the internet can I find a die to make the boss. A fruitless couple of hours were spent trying to find an on/off /reserve tap with 90 degree large outlet pipe with a low profile and without vacuum opening.


I was about to put release agent on the seat and I noticed some corrugations at the base of the hump where the mould met the base board infringing the top surface for about 5mm. I rubbed these down with 240 W&D leaving a scoured patch c 10mm deep, this was rubbed down progressively with 600 then 1000 then 2000 and by this time *I found myself with virtually the whole hump rubbed down. I thought I might as well try and polish the surface with 4000 abra pads. Using these certainly shows up every single tiny imperfection, I found pinholes and corrugations in the mould surface that I did not know were there, also regrettably very faint trace evidence of the original wooden skeleton could be discerned preserved in the gel coat. All this took about an hour. The advantage I hope will be releasing the CF part from the mould will be a lot easier with a highly polished mould.

[350TSS]

The tank underside now with 2 gel coats, one coupling coat with 100g mat and two polyester resin coats with 300g mat. I hope to finish tomorrow with 2 more 300g mat coats and then split the mould 4 ways the day after when the resin has fully cured.
I have cut cotton patterns for the CF cloth for all the smaller moulds; the tank obviously, the seat, the hugger and the fly-screen still need to be done.
I have been thinking about the engine work I need to do and I definitely need to replace the fixed belt rollers as these were seized in and I had to weld nuts to the ends of the stud to get them out. Replacement fixed belt rollers are part number
45120211A @ 41.98 Euros each plus postage from Stein Dinse
so not much change out of £90.
Can anyone think of a good reason not to use 4 bearings as used on the adjusting rollers retained by a wire locked titanium bolt? This can be done with top grade bearings and Grade 5 titanium bolts for about £35 (although I may need to make a couple of spacers for the inner race to cylinder block interface as the original bearing has a projection there).
The side loading on the bearings cannot be much different as between the adjusting rollers and the fixed roller so the bearings should be up to it and I cannot think that a cam belt can exert enough force to sheer a 10mm titanium bolt. Bolt retention issues arising through differential expansion rates of aluminium and titanium and heat cycling may be problematic but with Loctite and a wire locking arrangement in place that should deal with that. Clearance between the bolt head and the CF belt cover should not be an issue and in any event the bolt head should not be spinning. The only other problem I can foresee is that the original fixed bearings may have had the outer surface ground slightly (domed profile) so that the belt self- centred but I think that unlikely as it would stress the teeth on the belt and since I have thrown the old ones away I cannot tell that.

[350TSS]

Today was about removing the 4 parts of the tank mould from the pattern.
The tank top (in 3 parts) came off in half an hour and I was delighted to see that the mould was true and will not require any work apart from polishing, even the flash line down the central split was crisp and not too intrusive and so my day started really well.
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The bottom part put an end to that. I tried for about an hour to get the pattern off without damaging it, when you have spent so long making something you are naturally reluctant to destroy it. Eventually I unintentionally damaged the pattern and at that point realised that it was not logical to preserve the pattern (what would I do with it? - the important bit is the mould) so the wood chisels were put to use. An hour later it looked like this:



And two hours later it looked like this:


The reluctance to separate is definitely not due to insufficient release agent and I am almost certain it is nothing to do with mechanical locking I can only put it down to the surface on the tank underside not being polished.
I did spray it with the high gloss resin but left the finish “as sprayed” because it was the underside of the tank and because it is really difficult to rub down and eventually polish convoluted concave surfaces. I think there was sufficient “orange peel” effect on the surface of the pattern to cause the gel coat to grip the surface. Another hard learned lesson which means I think that before laying down the CF gel coat I will have to spend a few hours polishing the now convex surface.
I also cut the cotton pattern for the seat mould and after a few attempts at a one piece pattern reluctantly concluded that the CF would have to be cut in three pieces a) the seat base, b) the riser for the hump and c) the hump itself. I will need to lay up the CF with the hump part first so that one does not see a ragged edge in the finished article where the riser meets the hump. I will obviously reinforce the junctions between the three cut pieces during the lay-up of the CF.

[350TSS]

As an aside I thought some might be interested in this creation (Australian)
A crashed Merlin engine had 2 cylinders cut off and grafted into this. Lots of long straight roads in Australia so I'm told.

[Darren69]

Its like something from Mad Max