Jeff,
I just roughly measured my BMW R100 transmission. It is roughly:
10" wide
8" high
7" deep
The input/output shafts will stick out the front and rear past that a
bit, and it is a bit of an odd shaped thing, so those are rough
dimensions only. I think it weighs about 30 lbs. - it is a heavy little
chunk, but it is easy enough to pick up.
From memory, a long time back, the Norton gearbox is maybe 8" wide, 6"
deep, and 6" high. It is maybe 20 lbs.? I carried one from San Diego to
the middle of nowhere in the Baja desert in 1976, and it didn't seem
that heavy. The clutch (splined input shaft) is on the left, with the
output sprocket (splined shaft) on the right I think. Shifter on the
older ones ('73 and older) was on the right, later ones had a mechanism
to move it to the left.
Hope that helps a bit.
Kevin
Courtenay, BC, Canada
Jeff wrote:
Kevin,
Thanks for the info on sources of self-contained transmissions. I would
think that would be the ideal for my situation, but it doesn't totally
preclude the others. Compact size is my primary concern, followed
closely by the ability to have a wide-range-reduction gear set. I'd
personally prefer to design for splines than keyways. Keyways always
seem to acquire slop and ruin the driveshaft and anything it's connected
to (at least on a wheelchair).
Self-contained would certainly make for easier maintenance.
I had some questions (everyone here will either roll their eyes, or
groan) about the general size and weight of transmissions. I know from
your links and from other stuff I've found on the net that this is all
hugely variable, but are we talking (on weight):
10-30 pounds?
20-50?
40-80?
It would be great if I could find out what sort of ballpark we're
talking about.
Can you ballpark on the sizes, too?
It really is a major production for me to get to any sort of bike shop
-- or anywhere for that matter. If I could find a place on the net that
had some of this info, it'd be great.
Jeff
Ok, I just found an interesting site:
Dan's Motorcycle Repair & Engine Repair Information Guide
<http://www.dansmc.com/index.htm>
DAN'S ONLINE MOTORCYCLE REPAIR COURSE
http://www.dansmc.com/MC_repaircourse.htm
Dan's Motorcycle "Shop Manuals"
http://www.dansmc.com/shopmanual1.htm
Kevin Caldwell wrote on 12/01/06 21:17:
There are a few other sources of separate, self-contained motorcycle
transmissions than Harleys. All the '60s and '70s Nortons, Triumphs,
and BSA's had separate 4 speed transmissions. The clutches sat on the
transmission main shaft, and were driven by a 3 row chain off the
engine around the outside of the clutch. They are reasonably small.
They might be getting to be parts for collector's bikes at this point
though. Still might be worth a look at a wrecker or eBay
BMW airheads had separate transmissions into the late '80s at least,
and they are 5 speeds, but they are set up for shaft out, and a
spline drive in.
There are a few on eBay right now:
Or you might find one at:
http://www.ibmwr.org/market/adlist.php?cat=aps
The self-contained ones would be simpler to use. All the Japanese
"unit" bike transmissions are so built-in to the engine, and are
usually gear driven, it would be a bit messy to seal them off to use
separately. Not impossible though. They usually just run with the
engine oil, whereas the separate ones all use 50W - 90 (or something)
gear oil which is quite a bit thicker, especially at cold temps. With
your loads, they'd be fine with 10W - 30 engine oil though.
Kevin Caldwell Courtenay, BC, Canada
