10 August 2007

Impressions, observations, and wild-ass guesses...

Clicking will make it HUGE!

So how come I didn't notice that my yard needed weeding until I saw it in that picture? Where's that Meskin...but I digress.

That's Mrs. G's new '06 Buell Blast (backstory here and here). By now I've had a chance to think about it, look it over, poke it and and prod it some, and even ride it a little. Here we go...

I think it's a very pretty bike. It's got modern styling, which doesn't always work for me on some bikes, but on this one it does. It's a small bike, but everything's in proportion. A lot of new bikes are pretty angular, but this one's round. In my view, motorcycles should be round in styling, more pleasant to my eye than a buncha harsh angles. Score one for the styling department. I like the color, too.

The heart of any bike is the engine. This one is conventional and unconventioal at the same time. It's coventional in the sense that it's an air-cooled pushrod-operated overhead valve 500cc single-cylinder layout with two valves. It's unconventional in the sense that this is a traditional layout since the dawn of time which fell out of favor over thirty years ago in favor of overhead-camshaft engines, which make more power because they can rev higher and have less moving parts in the valve train to have to throw around.

It also departs from OHV tradition in that the bore/stroke relationship is undersquare, meaning the stroke is shorter than the bore diameter, which lets it rev higher than the old long-stroke singles, which had bags of torque but only produced a power stroke about every other phone pole. Redline comes at 6500RPM, fairly high revs. There's no tach, but revs are limited electronically by a spark randomizer, which is a pretty common way these days to avoid over-revving and the resultant attempts of the engine internals to exit stage any whichaway, or as us pros say in techspeak, "go blooey".

The Buell company is owned by Harley-Davidson. The engine was derived from the Sportster V-twin and pushrod engines are the only type of four-strokes that H-D has built for about the last hundred years until the recent OHC V-Rod. That's not new. Vincent made a line of singles such as the Comet model out of their V-twin Rapide sixty years ago.

We can leave H-D's old ('40s-'60s) 2-smokes out of this for now, but just as a point of historical interest, they were copied from the German DKW as spoils of WWII, along with the BSA Bantam and early Yamaha 125s. Hey, why design an engine when you can liberate one?

The Blast engine is 'dry sump' which means it has an external oil reservoir and a separate gearbox/primary oil supply. That, too, is old-fashioned and it works. It has an added benefit of helping to cool the oil as well.

On to the Frame. The Blast barely has one. It has a rectangular steel tubing backbone, which doubles as the oil tank, from which the engine is hung. There's a short stub extending downward from the steering head which connects to the engine via a Heim joint rod, which, along with one to the rear, serves as a top motor mount.

Since there's no frame tubes under the engine, a no doubt truly expensive set of crankcases are left vulnerable to damage from running over curbs, pedestrians, etc., Buell has protected the mill in a very clever way, I think. The exhaust pipe segués neatly into the muffler directly under the engine. The line of the pipe follows the curvature of the front wheel for eye appeal, and resembles a 'chin' fairing used on some bikes as an an air intake for various purposes. A little dab of 'fool the eye' put to good use. The muffler is triangular in shape, which makes it look aerodynamic and won't high center on anyone you run over.

Speaking of engine protection, take a look at the footpeg support, the Y-shaped pressed steel bracket extending downward from just under the front of the seat. Since this a supposed to be a 'beginner' or 'starter' bike, this is a real good idea. It won't do much good at anything over walking speed, but that's when beginners tend to tip over. Bikes self-stabilize once they get going. Don't ask me how I know this, but they actually work. The slight drawback is that they need to be removed for some service work, like adjusting the clutch or changing the gearbox oil, but it's only two bolts per side.

I've got more to say about this neat little sled, but the pups are clamoring to get emptied and then it'll be lunchtime. Later.

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