manual/auto bikes?

[Z_Fanatic]

Ya it does make sense. I just shift it and match the revs intuitively, and it works. But I close the throttle all the way (except when clutchless upshifts), because to me, the motor still keeping high rpms as I pull in clutch to shift sounded abnormal. Referring to above 9k btw. But now looking back, it takes away reaction time. Same goes for downshift to pass a vehicle, it's a lot faster to simply up the rpms while the clutch pulled in than just close the throttle and reopen again.

[jeffcoslacker]

Originally Posted by gsf1200m

Good point never though of that. But another thought that the bike could have a sensor incorporated to know the lean angle and whether the bike should be shifter or not.

Yeah that flashed through my head too right after I posted that...

You could concieveably do it with a combination of bank angle sensing, throttle position, lateral g-force sensor and wheel speed info from an ABS sensor, but mapping the control program for that could prove tricky, as it would send the engine management system into a tizzy because the motor would then be out of optimal RPM range and wanting a shift, but being denied because of the situation, so it'd have to either lug, or cut the throttle back, which would also be unexpected and unwanted in a curve...and if it delayed a shift until the bike was not pulling any hard lateral g, you'd have to match the engine speed to the appropriate gear, since now you might be out of optimal range for the next gear, which involves a couple of gear changes to skip over one or two....Just gets more and more complicated.

See what I mean? More complex than a simple go/no go decision from the tranny control, and the benefit vs. the potential liability just doesn't warrant even trying....

[gsf1200m]

This is an interesting topic so I searched automatic bikes. The first one that came up was "Honda Previews 680cc Automatic-Transmission Motorcycle at Tokyo Motor Show."
This is how the article addressed the shifting during cornering. "Honda says the automatic shifts smoothly enough to avoid possible traction problems while cornering." Not nearly enough infor but theres another easy way to fix the traction problem. Not really high perormance shifting for a fast sport bike im guessing.

[jeffcoslacker]

Originally Posted by gsf1200m

This is an interesting topic so I searched automatic bikes. The first one that came up was "Honda Previews 680cc Automatic-Transmission Motorcycle at Tokyo Motor Show."
This is how the article addressed the shifting during cornering. "Honda says the automatic shifts smoothly enough to avoid possible traction problems while cornering." Not nearly enough infor but theres another easy way to fix the traction problem. Not really high perormance shifting for a fast sport bike im guessing.

Interesting...my guess would be that the Honda uses some kind of torque convertor more like a car's tranny, that doesn't require a drop in throttle and torque on the driveline to shift, where that FJR is just the same as a normal bike, just uses an actuator to work the clutch for you.

I remember reading something about Honda's early auto shifts, I don't remember the model it was offered on, but they had some quarter mile and 40 mph throttle roll-on data, and the auto was just dismal...something like 13 seconds for the standard and 17.5 for the auto, if I remember right.

But I bet that FJR is as fast or faster than the standard.

[MagicRat]

Originally Posted by jeffcoslacker

I remember reading something about Honda's early auto shifts, I don't remember the model it was offered on, but they had some quarter mile and 40 mph throttle roll-on data, and the auto was just dismal...something like 13 seconds for the standard and 17.5 for the auto, if I remember right.
.

I posted some links for the auto transmission CB450A and CB750A on page 1 of this thread.

They were really slow, and were tuned to be very smooth and pretty mushy.
They had an automotive-style torque converter and no clutch.
They actually did not even shift gears on their own. The rider would shift between a 'low' and 'high' range manually, so they actually only had 2 gears.
If you did not like to shift, you could just leave it in high all the time and let the converter slip to give you low speed opeation, but this would just make it slower.

(BTW it's not the first time this was done. General Motors used the same set up in their 1958 - only 'Turboglide' automatic transmission. It was a dog and was dropped after that year.)

I suspect they made it this way for simplicity and to provide easy surprise-free operation for beginner and novice riders, including no unepected shifts on the corners. I'm sure an experienced rider would never choose a transmission like this unless they had a physical disability.