O-ring position, Mototrans 125, 175 & 200e

[Geordie]

Item 82, page 27 of the parts catalogue.
When I stripped down the motor there was no o-ring present in that area - outside the crankcase right half.
Does anyone know its intended position please?

[Jon Pegler]

The only O ring in the RH case seals the selector drum shaft.
It is fitted into a groove in the RH case, between the inside and outside faces of the case itself.
What Mototrans parts book are you using? It's not on page 27 of any of my parts books.
No. 82 on the RH parts book drawing is drawn a little out of place, looking like it should be nearer the timing gear area, rather than further back at the selector drum.

Jon

[Geordie]

Jon, thank you for that. The parts book I am using is

PARTS DUC.png

It is the only readable Spanish copy I could find online but don't recall where - the Lamaneta.com photocopy is v poor.

The second of the parts illustrations - Cambio Velocidades - shows no o-rings (retens).

The RH case illustration (page 27 my copy) has the o-ring which I now assume is as you describe - for the selector drum shaft.

RH CASE DUC.png

An o-ring is shown in position as you describe in the Italian workshop manual.

SELECTOR DUC.png

Searching my memory, I cannot convince myself that I replaced it (75:25)! I will have to split the crankcases again to check - a good thing that it is a hobby so I can justify the hours as amusement

If you would like a copy of the parts book I have, PM me and I'll zap you one.

Ian

[Geordie]

Well, it was in position! Anyhoo, I'll take the opportunity to make a new centre gasket as the pre-cut one bought was inaccurate at the sump section. O-ring replaced anyway, while it's open.