Shifting Gears On A "Semi" Auto Scooter

[CanInBKK]

I ride my CBR daily and my ninja on weekends so a manual tranny is no problem, ditto with a full auto scooter. But this past weekend I was upcountry and a friend lent me their semi-auto (4 gears, no clutch, kick transmission) and I found it ridiculously jerky. I know it's me and not the bike, so the question is what is the timing sequence to shifting? If I rev and then let off to shift it kind of lurches, if I don't let off and shift it jerks. Downshifting when coming to a stop is an even greater challenge! What's the secret?

[dave_boo]

One thing I do if riding such a bike is actually modulate how much I let the shifter return to centre.  You can almost use the shift as a clutch that way....still not 100% but much better than the usual jerking.

[VocalNeal]

It is a misnomer that there is no clutch, there are two. One centrifugal that does the off-the-line work and the conventional clutch that is operated by the gear shift pedal.

I used to ride normally and change gear normally without noticing any problems or maybe it was familiarity...

It maybe that the gear shift clutch is or was not adjusted properly, a 30 sec job at any motorbike shop. That is what the screw-like device sticking out of the "crankcase/gearbox" at the rear on the right hand side is for.

[thrilled]

I've found that those aitomatic type cluthes aren't anything to brag about.I only ride bikes with full clutches manual transmissions,5 and 6 speeds.

[dave_boo]

I've found that those aitomatic type cluthes aren't anything to brag about.I only ride bikes with full clutches manual transmissions,5 and 6 speeds.

Think this wins the 'most useless reply to original topic' for the day award.

[VocalNeal]

I've found that those aitomatic type cluthes aren't anything to brag about.I only ride bikes with full clutches manual transmissions,5 and 6 speeds.

Think this wins the 'most useless reply to original topic' for the day award.

I guess a 7-speed Mito would be no good for him? Too many.

[Garry]

It is a misnomer that there is no clutch, there are two. One centrifugal that does the off-the-line work and the conventional clutch that is operated by the gear shift pedal.

I used to ride normally and change gear normally without noticing any problems or maybe it was familiarity...

It maybe that the gear shift clutch is or was not adjusted properly, a 30 sec job at any motorbike shop. That is what the screw-like device sticking out of the "crankcase/gearbox" at the rear on the right hand side is for.

Definitely agree. Just a case of the OP getting used to being smooth with the clutch engagement on the gear shift lever/pedal. Practice makes perfect. My wife is as smooth as silk on her father's older bike (Honda Dream).

[Familyonthemove]

It's years since I've ridden a step-through Honda ... but in ye-olde Honda 90 track-bike days the trick was to roll off the 'power' and put pressure on the pedal to engage the clutch then let it clunk into the next gear. The pedal was a heel and toe thing that could be shifted up or down just by angling the foot.

A bit like a clutchless change on your normal geared bike .... but with no chance of a high-side if you get back on throttle too soon!

On a related issue - I nearly high-sided my Nouvo 135 at the weekend ... Wet rear tyre on a polished concrete car park .... now that would be embarrassing .... most feeble high-side award for 2011!

[CanInBKK]

I see…so effectively, I should press down on the rear of the shift lever (normally I would flick up on the front but for some reason these shifters are bit stiffer than either CBR or ninja), and gradually release the lever up as if gradually releasing the clutch?

[Garry]

I see…so effectively, I should press down on the rear of the shift lever (normally I would flick up on the front but for some reason these shifters are bit stiffer than either CBR or ninja), and gradually release the lever up as if gradually releasing the clutch?

That's about it. Just try practicing the action slowly & smoothly at first and you will get faster with practice and miles ridden down the road

[MaiChai]

The reason the gear shifting is harder is because it disengages the clutch before the gear shift. That effort does the same as you pulling in a manual clutch.

As another poster said you have two clutches; one just mentioned and a centralfrugal which are brake like paws that fly out as the revs increase. These paws flyout and contact with a metal flywheel. The paws are made from very hard brake material which over time cuts into the metal of the flywheel, and thus the flywheel gets grooves cut in it and can mate with the paws off center giving a juddery pick up. Solution is to replace the flywheel; I replaced one on a Suzuki smash and it was about 800 baht original part no labour. Its an expensive part, hence why most Thais can live with a juddery pick up.

[jdinasia]

I have been riding a semi almost daily since I arrived in Thailand (Joker) and found that simply taking the middle path from your original post works for me with no issues, CanIn

I don't rev and let off then switch gears. I don't hold the throttle in the same position and change gears. (Revving tricks the centrifugal clutch into thinking the bike is going faster than it is ... and keeping solid pressure on the accelerator doesn't give it a chance to adjust.)

I simply let off the accelerator a little and change gears. It works fine.

I don't notice any jerking, hesitation or fuzziness at all this way. It took getting used to for me, and the first year u=in the mountains was a bit ugly on occasion