239 Mk3 gearing

[Dodge]

What was the standard factory fitted gearing on the 1974/5 Mark3 239cc bike (with clip-ons)? Was it the same on the French market models? I believe that it was different to the 250cc standard bar bikes.

Roger

[Duccout]

FWIW, Mick Walker lists the 239 as having the same gearing as the Mark 3: 2.812, which corresponds to sprockets of 45:16.



Colin

[Jon Pegler]

Not forgetting that the primary drive ratio was different on the 239s, with a 25 tooth crankshaft gear and a 62 tooth clutch drum, rather than the standard 24/60.

[Duccout]

I wonder why the factory went to that sort of trouble, for such a low-volume production run?

[Dodge]

The gearing on my bike is 15/42 which works out at 3.00. Seems very high to me, which is why I asked the question originally. The rear sprocket is drilled with holes to reduce weight. I don't believe that this was Ducati standard. However, I have owned the bike from new and have no recollection of the gearing being changed. The bike was purchased from Jack Lilley in Shepperton (who probably acted as agents for C&H). The only other mechanic who got anywhere near it was "Bernies", who I think was in Walthamstow or was it Dalston?

[Smoggy]

I recently joined the Forum after viewing posts as a guest and thought that I would add to this post as there aren't many 239s about. When I bought my August 1975 registered 239 (valve spring) as a non runner in 1982 it had only 3928 miles on the clock having spent most of it's life off the road so I believe that the final drive sprockets are as fitted by the Factory. It has the 25/62 primary drive as mentioned by John Pegler and 15/45 final drive sprockets, the rear sprocket is undrilled. I am fortunate to have the "Front Counter" copy of the 1974 factory engine parts catalogue from Mick Walker's shop, obtained when I visited Mick at his home in the summer of 1982 to exchange a 175 basket case plus spares for various spares for the 239. There are various handwritten additions to the catalogue detailing the differing part numbers of the 239 models but there aren't any handwritten entries in the gearbox/clutch section, just the 24/60 part numbers for the 250s and 27/57 for the 350/450s. I think that this may indicate that Mick Walker was unaware of the change to the primary drive gears on the 239s when he was writing his restoration guide as the quoted ratio of 2.5:1 is the same as that for the 250s.

Dave

[Paradiso]

I wonder why the factory went to that sort of trouble, for such a low-volume production run?

I think it was something to do with the vehicle tax regime in France.

[themoudie]

I wonder why the factory went to that sort of trouble, for such a low-volume production run?

I think it was something to do with the vehicle tax regime in France.

Aye Paradiso, it was everything to do with the French road taxation system.

Good health, Bill