Sunday, 12 December 2010

Raiders of the Lost Parts

Despite the auguries to the contrary, I did actually manage to make some tangible progress on the BMW this week. It started badly with my trying to get some one on the phone who knew about Acewell digital speedos, as I'm a bit unclear about which would best serve my needs, and failing miserably at that.

Havng arrived at Friday slightly tired, dazed, and not entirely sure why I was in the workshop, I turned around and got back in my car, and instead of doing the sensible thing and heading for home, I went to B&Q and bought a length of 12mm threaded bar, and some suitable nuts and washers.

 The reason for buying it was that I couldn't find the original fine thread nuts that went on the two original engine mounting studs, which meant that I couldn't tighten the engine mounts, which in turm meant that I couldn't make sure that the frame splices were correctly aligned. While threaded bar isn't suitable for use as an engine mount, it can certainly substitute for one right up to the point where the engine is fired up. Certainly in the past, I've noticed that people assume that because I've used it while constructing a frame, it's going to fine as an engine mount. The truth is that I use threaded bar for these applications because its' more convenient, the coarser thread saves time winding nuts on and off, and if I damage the thread then I haven't wrecked a stud which will have require more investment of time, energy, and often money to replace. Once I'd cut a couple of lengths of threaded bar, I cleaned up the cut ends of the frame rails and bevelled them and the splices ready for welding.

Aside from the nuts for the engine mounting studs, I'd also managed to lose the steel template I'd made for the gusset to go between the existng factory headstock bracing. At one point on Friday, there were three of us searching for it in what was in increasingly unlikely places. I eventually found the thing in plain view of everyone. I'd left it on the bench with the gussets that I'd already made, and some how it had got knocked off of the bench, whereupon the force of gravity had taken over. I'd suspected this as a possibility and had assidously searched the floor area around the bench in my quest to find the thing. What I should have remembered is that gravity is a very weak force, because on it's way from the bench top to the floor, the template had passed the magnet that lives on the side of that particular bench, and magnetism being a stronger force than gravity, it had snatched the template for its own. Which goes to show, even particle physics can come in handy from time to time.Having found the template, I went on to make version 2 of the gusset, and add it to the collection.

Saturday dawned a much warmer day than had been the case for most of the week. I know that because after I woke up in the middle of the morning, I was told so by Samm, who knew it because she'd looked it up on the Internet. Rolling into the workshop at around half past one, I started plodding my way through the welding, and sorted out the detachable frame rail.

With that done I double checked the headstock gusset gusset, which I suppose ought to be called a boxing plate. as that's more or less what it's doing. With that finessed and tacked in place, I tacked the rest of the reinforcements  in position, then preheated them with my propane torch and welded them.

I mentioned last time that the top tube to down tube gussets were going to hidden by the tank, but that the determined obeserver should be able to spot them, and as you can see in the last photograph, that is the case.

Because I was getting tired and my welding seems to suffer for it, I opted to wrap it up as soon as I started fumbling things rather than press on and do the few remaining bits of welding. I'm hoping I can get that done in the week and then start reassembling the motorcycle to make and finish off any odds and ends of fabrication, before I make a start on the engine as I'm hoping to get the paint and so on done while I'm overhaulng the drive train.

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