Subject: RE: Longitutal engines and shaft drive
Author: John Engelhard
Date: Jan 27, 2002, 6:49 PM
Post ID: 1709499575
The longitutal layout is more direct for shaft drive applications by
eliminating a set of crown gears at the transmission output shaft but it
does allow the engine torque to rock the motorcycle a trait that can be
especally alarming during full throttle shifts between first and second,
the heavy flywheel only intensifies this effect. That engine torque is
working on the frame in a direction that it is least able to cope with.
Of coarse to overcome this Guzzi had to build an especially robust frame
using the engine/transmission as a stressed part and since under most
conditions the engine is not trying to twist the bike around you end up
with a very stable platform that makes the bike handle very presicely.
If you compare the construction of the forks, headstock and especally
the swing arm pivots of a Loop Frame Guzzi to any of its contemporaries
you can see why this bike could carve corners as well as or better than
any of the sport bikes of its time. Another disadvantage of the
longitutal layout is way it spreads out the drivetrain. Back in the 60's
a 58" wheelbase was hudge, of coarse now nobody makes a bike that
length. Either they're sport bikes with "stacked shaft" transmissions to
get the wheelbase down to 54" or they're cruisers where even the 650s
have 65" or more between the axles. Honda addressed this on the CX by
placing the primary drive in front of the engine and the transmission
along side. If you park a CX500 next to a Guzzi you'll see the Honda is
much more compact but the bike ends up a lot taller for some reason.
The problem with squishing the drive train like this is that the rider
need space for his legs and the cylinders start crowding in on that
piece of realistate. This last fact has forced Guzzi to NOT follow the
trend of placing the foot controls way out front and I'm mighty glad of
that! That position might be great for the ego when cruising around town
but it's a bear on the butt when your riding all day.
OH MY GOD, I'M RAMBLING ON AGIAN! If you read this far you probably
don't mind and if it bothers you just hit Next Message!
John Boettcher wrote:
| Doesn't that configuration play nicely for shaft drive regardless if air or water-cooled? JB snip Remember the Honda 500, a longitutal
|
John Engelhard
St. Clair Shores, Michigan
1969 Ambasador V750A