What's a Benly 90?
When I bought the 1966 Honda S90 I didn't even notice that the little emblems on the tank had "Benly 90" written below the Honda wings. I posted a note the Yahoo S90 group about my new acquisition, and then found out that the S90 I had bought was a Japanese domestic model -- this means it was a home market bike, probably brought to the USA by a returning serviceman.
Benly 90 vs S90
By and large, the Benly 90 and USA market S90 are the same bike, but with a few differences. (Much thanks to the folks on the Yahoo S90 group for the information.)
- Small rectangular turn signals
- Smaller rectangular (tall rather than wide) rear brake light
- Different horn
- Benly 90 tank badges
- Enclosed drive chain
- One piece muffler
- Pressed sheet metal swing arm
- Non folding passenger footpegs
- Different sized footpeg rubbers
- Rotary shift transmission
As far as I can tell, my Benly 90 has all of these features.
Rotary Shift transmission
My little Benly 90 has the rotary shift transmission. This is apparently common on small bore bikes, though I had never heard of it before. The best way to describe it is to compare it to a standard USA market pattern.
USA standard pattern
1 - N - 2 - 3 - 4
With this pattern, you click all the way down for first gear, then shift up to get higher gears. Neutral is between first and second gear. Once you get to fourth gear, the bike will not shift any higher, nor will it shift lower than first.
Rotary shift pattern
N - 1 - 2 - 3 - 4 - N - 1 - 2 - 3 - 4 - [...]
With the rotary pattern, there is no top or bottom. The shift drum can rotate through a full 360 degrees, so when you get up to fourth gear you can keep going back around to neutral then on to first gear. The advantage is that when you come to a stop you can shift quickly back to first without having to go back through all the intermediate gears.
The rotary pattern is down (toe shifter) to go up gears -- so from neutral it's one click down for first on the toe shifter, then down again for second. This is the reverse of the modern pattern of shifting up to get higher gears.
The big disadvantage is that if you forget the bike is only a 4 speed, you might inadvertently shift up from fourth into first! This could be fatal for the transmission and engine. In my limited rides on the bike so far, it seems that you hit a clear neutral first, so you just have to keep an eye out for the little neutral light. A bit of care is all that seems to be needed.