--- Mark Roberts <[EMAIL PROTECTED]> wrote: > >Ewww... I saw the tell-tale underseat triangulation but just > >couldn't believe that someone would cut up a beautiful Ducati > >frame for that huge and heavy lump of a four cyl engine... > > Actually, that air-cooled four is surprisingly lightweight.
LOL ... An "aircooled, four-cyl vs 90 deg VTwin" debate on the Pentax mailing list? Wonders will never cease. ;-) I dunno, Mark. Light as a 4-cyl 1200cc engine might be, it has got to be twice the weight of the Ducati 750 bevel drive engine unit. An air-cooled engine is generally speaking heavier too, due to all the finning and the increased spacing between bore centers required to ensure sufficient cooling. > ...requirements for a streetbike were, first and foremost, low > maintenance (and simple maintenance - no desmo valves!) ... More propagation of myth about Ducati valve gear. I've owned several four cylinder motorcycles as well as several Ducatis with desmo valve gear. In all cases, without a doubt, the four cylinder engines take more time to service and maintain, particularly when setting the valves. > .. reliability. Along with massive horsepower and a wide powerband. A big four has smaller, less-stressed cylinders and can produce more horsepower as a result at the same amount of stress on the engine parts. Thus overall longevity can be greater, assuming you run the engines at the same specific power level. However, in on-the-road practice, well-maintained examples of both turn up similar reliability records, and both have a wide powerband. The increased displacement of the four simply wins on total power output, and makes up for its heavier bulk and the effect on handling. > No one built a bike that met his criteria so he made his own. And that's the bottom line. I have built up several bikes to meet my particular desires as no one made exactly what I wanted, too. Specials like this can be delightful and work very well, if something of a bit of heresy and horror to the purists. ;-) I enjoy fours, v-fours, flat-twins, v-twins, triples, etc. All the configurations have their individual charm, positive and negative aspects. Most of my bikes have been modified to meet my desires in one way or another, I usually just don't get so radical as to require a wholesale frame conversion for a street bike. I build my bikes for the road, after all, and the different needs of road usage vs racing needs apply. When I was building road-racing bikes for money (in the dark ages before 1978...), I thought in terms of how many hours between rebuilds and how quickly a rebuild could be effected. Changing and modifying frames to achieve new goals was considered de rigeur... Bringing this back to photography, the differences between motorcycle engines/chassis and the character of the motorcycles they bring into being is much like selecting one of 7 or 8 50mm lenses for a particular rendering quality or flatness of field characteristic, eh? ;-) Godfrey __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
