Monday, September 18, 2006

300 Miles On

I've had a weekend to spend with my new stablemate, and here's a progress report.

The chassis is brilliant. While it's too long a stretch to the ground at a stoplight (and I've remedied this problem this morning with a lower seat), the moment you start moving any awkwardness vanishes utterly. The bike is very neutral and maneuverable, and the long-travel suspension easily sucks up anything you throw at it. In riding position and ride comfort it is a clear improvement over my last BMW.

The brakes are awesome, as expected. What I had forgotten about is now much a standard motorcycle--especially one with a long-travel front fork--dives forward with the weight shift of heavy braking. My BMW had an innovative front end that virtually eliminated brake dive, and it now feels a bit odd to have the chassis move around so much under braking. There doesn't seem to be any negative consequence of this, and indeed it's like every other motorcycle I've owned except for this last BMW.

My biggest question mark--the engine--seems to be growing on me. As I stated below, it has (a bit) more power than my last bike, and should be otherwise similar in riding characteristics--torque curve, power band, etc. But my BMW had no region in its rpm operating range where it seemed unhappy. This bike vibrates quite a bit at idle and up to about 2,500 rpms, beyond which it smoothes out comparable to my Beemer. One doesn't spend much time in this lower rpm zone, but you revisit it at each stoplight and whenever there is reason to slow the engine to idle. I suppose it's a question of whether one attributes the vibration to crudeness / lack of refinement, or to a necessary characteristic of this 45° V angle.

Maybe unexpectedly, I'm beginning to see the light. For we motorheads, an engine informs the entire machine, be it car or airplane or motorcycle. There is a huge dollop of personality invested throughout a machine like this from its powerplant, and nowhere more than with a motorcycle. And this engine simply overflows with personality. My BMW was similar, but its fuel injection was spottier. The Buell will pull strongly out of its low-rpm depths, vibration and all, and it keep on pulling as the revs climb, emitting quite the growl as it goes. In most normal riding, the RPMs sit in the 2,500-4,000 range, and this is a satisfying experience. The bike doesn't much care what gear you're in, and there is only the rising vibration as you slow to tell you to shift down--if you want; it's happy to lug. Overall, I didn't expect to like the motor, and I'm starting to think it a most worthy soul to the machine.

Lastly, the whole implementation is much better than I expected. The harmony of the suspension, front & rear, and the drivetrain refinement make for a really first-rate riding experience. I had somehow expected the bike to be no better than the sum of its parts, and I think that expectation was incorrect: several times over the weekend I was surprised at how invisible the machine was from an operational standpoint, how little adjustment I needed to make to accommodate Erik Buell's handiwork.


Jeffy said...

Glad to hear that the engine is growing on you - it sounds like quite a fun bike.

I've been thinking more about the brakes with the rotors way out at the rims. That just seems like such an obvious win-win deal it is hard to imagine that it hasn't been done before now. There appears to be no downside at all, the rearrangement improves everything.

As for the dive when braking, while it is pretty common, I think that it does impact performance. By shifting the center of gravity forward you lose weight on the rear wheel - so it is even more useless for stopping, and more inclined to slide out to the side. Also, by putting more weight on the front wheel you affect your abililty to control the bike while braking, so it can be harder to steer, especially while braking harder.

The systems like your BMW had to reduce the dive are probably not simple systems, so there may be some real trade-offs associated with them (like weight and suspension response).

That probably highlights one of the primary appeals of the Buell - it is a very well-designed 'basic' bike. It gets the bulk of the job done as well as possible with no extra frills.

wunelle said...

I think the only potential downside of the perimeter brake (which Buell calls the ZTL, or Zero Torsional Load, brake) is that rotating mass is flung out by the rim, making for greater gyroscopic effect. But the overall reduction in weight would seem, to me, to counteract this. Also, most racing motorcycles now have such large brakes--they fill the entire inner wheel--that the differences in rotating mass can't be that great.

As for BMW's anti-dive, it actually was how the bike was suspended rather than some mechanism to keep the fork from diving. The braking forces were transferred from an A-arm just above the wheel directly back to the engine (part of the chassis), rather than flexing up through the triple clamps to the steering head. So it was simple and light. (They call it their Tele-Lever.) The Buell has a standard arrangement, though with an inverted fork (and a large one), there is almost no flex. But the fork dive does change the steering head angle, and so the bike's response to steering during braking.

I guess one of the changes for 2007 is a new, triple-rate fork spring, which I imagine can be retrofitted. That and the lower seat, now standard, are the only changes. (I had hoped for ABS, and might have waited for a 2007 model, but he said there was no such option yet.)

I'm hoping to take a ride over to MN this week.