Honda Cub / Chaly Automatic ?

[Benni]

Hello BBers, espacially those with a little Honda under them in younger years.

One lucky collector in germany has bought a very special Chaly, with the legendary 50cc OHC two valver,

but with a full automatic 3-gear transmission.


See, no shift lever at all, very strange.

The parts list shows the innards of the transmission :


Seems to me that a small centrifugal clutch for getting rolling from standstill is coupled with
a 3-speed planetary gear that can shift under full load, I have seen similar ( but bigger) versions only on Drag Bikes.

There even is a membrane valve between carb and head to avoid PRM surge in-between shifts, clever Hondas people.

Has this version ever been sold in the UK ? Did anyone here take one apart and was flabbergastered by those tricky mechanisms ?

[Alex@POD]

I had a suzuki ts50 with a 3 speed auto gearbox, I did take it apart but that was after it had broken to bits!

[Benni]

Just one slight bump, seems that is indeed a rare example of Honda over-engineering.

From the CM50 AMB official code and parts lists, it seemed to me that it was also sold in UK.

Anyone had one, rode one, opened it up ?

[Krikkit]

Correct me if I'm wrong, but isn't it a triple centrifugal clutch instead of single?

i.e. Different clutch weightings kick in at different output shaft RPM, with the smallest clutch being linked to the input shaft? Hence the planetary gear setup to combine the two.

[Benni]

This seems likely, the new owner is doing some test runs uphill to see if automatic downshifts happen under load.