Saturday, 22 January 2011

Spaced Out and Going Nuts.

In a slightly unusual turn of events, rather than not spending any time on the BMW, this week I've probably spent too much time on it. The net result of that rash expenditure of my life isn't wildly apparent to the casual observer though. For instance the fact that the ignition coil is now mounted will escape most people as it lives under the tank, and the tank spends most of it's time on the motorcycle. Though to be fair, most people would just assume that the coil had somewhere to mount and not give it a huge amount of thought.

The bracket I came up with was rather uninspired looking considering I spent most of a day thinking about how to make it.  In the end I abandoned all manner of over complicated thoughts and settled for making the mount from a piece of 1/2" strap with a couple of sets in it. Though looking at it now, I of course have what seems like a brilliant idea for something different. Luckily, as you can see, I only tacked the bracket on. I made a mount for the horn too which was a simple "L" bracket that welded to one of the small diameter brace tubes. I obviously felt happier about that one as I fully welded it.

It's fairly obvious that those two brackets didn't alter the appearance of the motorcycle, but it wasn't going anywhere without an ignition coil, and it wasn't going anywhere legally without a horn that at least worked for as long as it takes to get an MOT. Aside from the coil and the horn, I need to find a home for a regulator, a rectifier, a fuse box, and probably a few relays. Before I find homes for them however, I need to find them.

While those components are still noticeable mainly by their absence, other parts of the motorcycle were definitely noticeable by their presence, the tail end of the two Allen bolts, and their nuts that provide the location for the front of the seat base were protruding in a fashion that implied the possibility of a truly cringe worthy injury, so I cut, drilled and threaded some 1/4" plate which I then welded to the base (the mounting hooks are adjustable, so the pins don't need to be) to provide a permanent fixing that would work under the upholstery, and remove the risk of deeply personal injury. 

I also got around to removing the factory fitted front fuel tank mount and replacing it with one that positioned the front of the R80 tank where I felt it belonged. The presence of an R80 to compare notes with notwithstanding, then where I felt it had to go was all I had to go on.

With the tank provided with an almost complete set of mounting hardware (I'm undecided whether to attach the rear with hex or wing nuts) it seemed like an idea to turn my attention to the drop out frame rail. The counter bored recesses in the Suzuki Bandit splices fit the head of a 10mm Allen bolt admirably. Sadly the Euro standard 17mm AF 10mm x 1.5mm nut, doesn't want to fit into it. As a solution, I bought some stainless steel 10mm couplers or tube nuts. Popping them in the lathe and turning the hex off of one end so that it would drop into the recess in the splices and then shortening them and facing the end off didn't take stupidly long, and the nuts themselves were less than a fiver from the guys down the road at Avon Stainless Fasteners (0117 972 8560) .

Having sorted the nuts out, I discovered that I didn't seem to have any suitable Allen bolts, all the ones I found having either no shank, or too much shank. Rather than get back in the warm car, with its heater AND electrically heated seats, that was still warm from driving the thing, warmly and comfortably, up to the workshop, I elected to remain in the cold workshop and use a die to elongate the threaded portion of some M10 Allen bolts to achieve the desired shank length, and the saw off the excess threaded portion to make four suitable stainless fasteners.

Stainless of course is a poor conductor of heat, and while I don't know for sure, I'd imagine that titanium was an even worse conductor of heat. Certainly my right thigh and its accompanying titanium orthopaedic nail, gave the impression of being a bloody sight colder than the stainless Allen bolts.

Despite the COLD, it didn't take an awfully long time to modify the four bolts I required and fit them so that the drop out rail was properly secured. I may be preaching to the choir here, but the point of that particular piece of rigmarole was to ensure that the shear forces on the frame splices were bearing on the shank of the bolts and not on a threaded portion, spreading the load over a much larger area that the peak of a single thread. Aside from deforming a lot less easily the shank still has all the material you need to cut off to form the thread, and so it is blessed with a much higher shear strength than the threaded section of the same bolt.

At that point, I was reasonably satisfied with what I'd done because although the motorcycle didn't look any more finished I knew that the list of horrible little jobs that still need doing was quite a bit shorter. Were it an actual list rather than a hypothetical one, I could tell you exactly how much shorter... 

It being a hypothetical list, I was doing a mental run through of it, and got to the rear sets. These were working in a businesslike fashion, and doing the things they were supposed to do, though a little sloppily in all honesty. The first thing I did to remedy that was to machine some new, and somewhat more accurate, pivot sleeves for the levers. When I was making them originally I'd managed to make one of the sleeves too long, meaning the lever was sloppy from side to side as the design relies on the thrust face between the lever and the footrest and mounting washer to reduce wobble from side to side rather than the somewhat narrow bore of the lever acting as a bearing. Too long a pivot sleeve, and the lever is floppy and unpleasant to use, too short a pivot sleeve and the lever is pinched between the footrest and the mounting washer and can't move freely. The problem arose because I manged to lose my digital vernier and was having trouble measuring things accurately with a 50 year old set of Mark 1 eyeballs.

Apparently, you can buy a new digital vernier caliper on E-Bay for less than a tenner. This is much more sensible than waiting for them to appear in Aldi or Lidl at that sort of price, and beats the hell out of paying £40 for one over the counter at a tool supply shop. Turned up the next working day too.

I also made some spacers to move the gear change linkage outboard a little so that the Rose joints didn't foul on the levers at either end. While this was a success in principle, it looked like crap, and I'm going to have to do something a bit more discrete. I'm thinking about some 6mm spring washers between the lever and the Rose joint, as that should provide enough clearance.

Sadly, Avon Stainless aren't open at 6:30pm on a Friday, or as far as I know on a Saturday, so that's going to have to wait.

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