White stripes

Some progress again at the weekend, although whether this is enough is anyone’s guess.

First up, as I promised, are some turnbuckles to adjust the tension in the chain. Here’s one of them, although admittedly it’s hiding behind a bit of chassis. Essentially it’s a right hand threaded rod end, a left hand one, and a length of hex bar with a right hand threaded hole in one end and a left hand threaded hole in the other. You can just twiddle this around to change the distance between the two rod ends, thereby moving the diff carrier and tensioning the chain. There’s another one of these, exactly like this, on the other side of the diff.The idea is that I can easily make some bits of bar of different lengths, should I need to adjust the diff beyond the adjustment range of the turnbuckle. What’s more, I can swap it around to that it articulates onto the mounting at the other end, when the diff is positioned right to the rear of the slot in the mounting plate.

Something else that’s arrived is a quantity of expensive wheels from Compomotive. Here’s one of them bolted up to the rear hub.

The main reason for doing this is to check whether the handbrake levers fit properly and they do indeed seem to do so. I’ll need to make sure that the cables don’t go too slack as in that case the levers can move over and touch the inside of the rim. However, I’d probably hear the horrible noise so that would be OK.

So, with that checked out I could go ahead and finish off the handbrake. As planned a while ago I ran a cable to each of the rear calipers, attaching the cable to the lever by just looping it around the lever, and to the compensator I made a while ago. The lever then pulls on the compensator by a pulley arrangement to get a bit of mechanical advantage.

Hauling on the lever at least showed that the rear wheels were stopping to some extent. I’m not at all sure that it’d pass a proper MOT, but it’s fine for a race car where the handbrake is really only used for stopping the car moving on the grid and holding it on the trailer while putting the wheel straps on.

While banging on about cables, I thought I’d try and fit the throttle cable. I’ve always been a bit worried that it was rather a long way to the throttle bodies and so it seemed. In the past I’ve used ATB brake cable for throttle cables as it’s rather high quality stuff. However, it seems as though I’m going to have to find something else for the throttle cable as the longest ATB brake cable I can find is 2.5 metres long which isn’t quite long enough. At least that’s correct if I’m trying to avoid sharp corners. Now, if only they made larger tandem ATBs I’d be OK.

It’s getting close to the time when I’m going to have to fit the bodywork properly so that I can know where everything else, such as the wiring, has to go. So, it’s time to consolidate the body panels that I cut up a while ago to stretch them. It seemed sensible that I could use the aluminium that I used to stretch the panels as a mould, of sorts, for laying up some GRP in the gap between the two bits. So, I spent a while putting some mould release wax on the aluminium, then putting some gel on the inside of the ally and laying up some CSM on top of that. I used some pre-coloured white gel as that’s not that far from the body’s colour and it’s easily available as it’s used for boat building. I even topped it all off with a bit of tissue so that the nasty sharp bits on the inside were not there. Mind you, it’s a while since I did any GRPing and I think I got a bit too much resin on it. I’ll work harder at consolidating the next bit.

As always in these things you wonder whether the mould is actually going to release, although resin doesn’t still particularly well to aluminium in any case, but it was quite nice that when I drilled out the retaining rivets the aluminium just popped off leaving me with this rather odd white stripe. However, it should be pretty easy to fill the holes, either with filler or a bit more gel, and rub it down smoothish. Oh joy, rubbing down bodywork, my favourite pastime. 🙁 There’s been at least one occasion in the past where I wondered why the thing I was rubbing down was going red, only to realise that my fingertips were bleeding…

2 thoughts on “White stripes”

  1. Hi Tim,

    These people do folding tandem bikes so they may have longer cables for your throttle as I imagine the cable needs a bit more slack to go round the hinges.

    1. Thanks Dave. However, “these people” is perhaps not as descriptive as you intended! 🙂

      Mind you, it’s occurred to me that using two cables, joined in the middle, is actually a good idea as it’d allow me to adjust it from the middle and use the permanently fixed nipples at both ends.

      T

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