Prototypes and packaging

09 Feb 2018

Alongside components that “can’t be repaired” one of my pet peeves is parts you can’t reach without disassembling half the vehicle.

Modern design and production requirements dictate that things are stacked in tight and packaged for fast factory assembly. So you can (maybe) understand why you have to drop the exhaust and remove engine mounts to access the alternator on some front-wheel drive cars (looking at you Alfa), but it’s a bit rich when you have to start pulling off wheels and removing panels to replace a headlight globes (looking at you…oh, forget it, the list is longer than you want to think about).

Which is partly why there’s been more than the usual ‘couple of beers’ pondering the proposed XR600R tracker seat/tank.

Knowing what you want it to look like is one thing, figuring out how to make it structurally sound is another…but bringing it all together so that it clears various bits and bobs and everything can be removed and refitted easily is a whole other ball game.

Stuff-ups like inaccessible headlight globes notwithstanding, it’s given me a whole new level of respect for car and bike manufacturers. It explains a lot of the ‘now why did they do it like that’ stuff you come across, and why concept bikes and cars seldom make it into production looking just like they did at their big show debut.

In the XR’s case, maintaining the integrity of the self-supporting monocoque seat/tank’s backbone (it’ll be a load bearing part) meant raising it up to clear the side tubes and abandoning the idea of using a single central mounting bolt at the rear. It also meant the moving the AC rectifier off it’s little perch on the top shock mount…which sent me down the packaging path.

The Aussie-spec XR600R is blessed with remarkably little in the way of electrical components – aside from the lights, horn and coil you’ve really only got the CDI unit, the AC rectifier and the regulator/rectifier/condenser unit to deal with. The first two sit under the seat, while the reg/rec hides behind the headlight cowl. Ideally the finished tracker will have almost bare forks wearing only a number plate with the lights hiding behind it so, together with the CDI and AC rec, the reg/rec and its condenser need to find a new home.

The most viable spot is under the seat ‘ducktail’. The seat/tank unit is intended to lift off as a complete unit, which always presented a few issues in handling the rear light, rego plate and indicator business – whether to use an electrical connector or make the whole mechanical structure separate – but now there’s all these electrical parts to consider…to say nothing of any possible need for a metal earthing point.

In the last post I rambled on about how bikes seem to like to build themselves, but the XR is definitely providing its own solutions.

Juggling the tank tunnel up and down to give the right clearance and strength led to a reference hole being drilled to line up with the top shock mount. Slipping through a 10mm steel rod suggested some mounting options, and when the now-unused AC rectifier bolt turned out to line up perfectly flush with the shock mount it was a no-brainer to drill out a bit of flat steel to give a nice level guide for setting the seat height.

And that was the eureka moment. A simple steel sectioned cantilevered off the top shock mount would provide a good rear mount for the monocoque and could be extended back to carry the electrical bits.

Problem solved then…or maybe not. There’s a couple of more rounds of prototyping to go, parts to be made, offered up to fit, and no doubt modified or consigned to the bin before starting again. It’s time consuming, can be frustrating, but it’s all very satisfying when it comes together…you just need to keep going until you get it right.

All of which put me in mind of something I saw working as a motoring journalist back in the late ‘80s. Fiat, having yet another abortive tilt at selling cars in Australia, shipped a bunch of us overseas for the press launch of the Uno and, as a bonus, a visit to the Ferrari factory.

Dutifully trooping through the not-terribly-prepossessing (back in the day anyway) Ferrari facility we stumbled across a group of concerned-looking blokes in shop coats clustered around an immaculately suited ingegnere. He was standing in the engine bay of what I’m tempted to say was a Testarosa (but could well have been a 348) gesticulating wildly and demonstrating that the part he was holding clearly wasn’t going to fit where it was supposed to.

We all had a good chuckle over that, but Ferraris generally turn out pretty good don’t they.