Bonneville America Forums Forums General Motorcycle Forums Other Bikes Automatic?

Yesterday I met a guy on one of those supersized scooters, I think it was a Suzuki Burgerman or similar. He bragged a lot about it, how he could ride it in any weather etc. He also mentioned it had an automatic gearbox, which got me thinking. Imagine riding in the rain, going into a curve a little too fast, leaning a bit more than you anticipated, trying to slow down a little and the thing decides to downshift! Wouldn't that be a bit of a nuisance? Or am I just being backwards here? Are we going to see real bikes with automatic transmission in the near future? Maybe something for the Harley crowd? Then they can attach that left lever to a bottle of Harley fragrance, so they can be sure to always maintain that new bike smell.

Go to www.ridleymotorcycles.com I saw their website some time ago. This company produces bikes with automatic transmissions, but the tranny is not what you think; instead of shifting gears, their bikes use CVT (continuously variable transmission). Essentially, this is a system in which 2 pullies (front/rear orientation) are used and these pullies vary their diameter continuously, thus maintaining RPM's in a peak performance range. One pulley represents engine output, the other transmission input. With the engine pulley small and the tranny pulley large, engine power is applied at low speed, while cruising speed is achieved through the evolution to a large diameter engine pulley and small tranny pulley. I've seen this in action but don't really know how the pullies change diameter. Magic I think!

all well and good but half the fun is shifting

Frank

Oh, I know what you're talking about. I think that kind of transmission was first invented by a Dutch car manufacturer named DAF, later bought by Volvo. It's also used in snowmobiles and mopeds. I've seen it in industrial transmissions, but then in a manual version. I think the automatic ones use gravity, as the rpm's increase, a couple of spring-loaded weights pushes the sides of the pulley closer together, thus changing the ratio. Not very energy-efficient. I've driven one of those old DAF's, the Swedish Postal Services used to use them, and it's not a very smoothe ride.

Hey Lars
You're also assuming that you'd ride one of these things like you would a real bike ...

Honda used to make a bike with a automatic transmission. Worked with a man who had it and loved it. I think it was about 500 cc. It was a neat bike , about 25 years ago.they haven't made it in years. You probaly can find one in cycle trader or E-bay

Cushman had a varidrive for a while along with their 2 speed manual shifter. Rear belt pulley was springloaded and the front was squeezed together by a centrifugal setup.
Some Eurobike, Husky I think, made a self shifting 4 speed that used a complicated set of centrifugal and over-running clutches for the local military.
Honda made an automatic 750 for a little while, but it didn't seem to be very popular.
I remember hearing that NSU was either making or working on a bike with a scaled down version of the Saxomatic transmission used by VW and Renault. This was a manual shifter with an electric automatic clutch.

Yamaha is comeing out with one this year, the FJR 1300...

Lexus uses a continuously variable transmission in it's new Hybrid RX400h. Has an infinite combination of gear ratios. I think there has been a very common application of the same around for some time - used in the modern helicopter.

The Suziki Bergman's variable speed trans is computer controlled. It does not upshift nor downshift on corners in the way a standard trans would. My barber has a 650 Bergman and rides with a local Yamaha bike club (his son is in it). He tells me he has no problem keeping up with the gang on their touring.

The old Hondamatic was a regular 2 speed trans, without a standard clutch, but instead, a centrifical clutch. You were not supposed to shift it from low to high while moving. For around town, you used the low gear. For highway riding, you started out (rather slowly) in high gear.

The Vespa GT200 Motor Scooter also has the same tranny.

Dan