Motoscrubs.com

Hi all,
I am completely new to here from the U.K. so please excuse me if I get stuff wrong until I get used to what I'm doing,
So......I have been riding, repairing, tuning, and cursing at Ducati singles for over 40 years, not sure not how many I have owned in total but at least 15 that I can recall, currently I have a 1974 350 mark3 which I bought brand new when I was 18 years old and am so happy that I still have it today!! I also have a relatively recently obtained 1975 250 desmo which I am presently rebuilding .......Which brings me to my first posting here.....the previous owner 'lost' (of all things) some parts from the desmo head....I have no valve springs, no valve spring bottom seats, no valve spring top saddles and no valve spring top saddle split collet retainers, basically he lost all the valve spring associated parts. Now I have managed to locate a source for a set of 160 monza valve springs which are the same as desmo springs, but having no luck with the other bits.(unless anyone on here knows of a source?)
Has any one on here tried a V twin desmo return spring set up on a single? I know I can use closing collars from a V twin with 8mm valve stems, but can I get some variant of the V twins 'clothes peg' valve spring to fit the singles closing rocker? I have set up and or rebuilt quite a few desmo heads but always with the standard lightweight hairpin springs.
Cheers,
Blethermaskite

Have you tried Nigel Lacey of Lacey Ducati? Or Classic Ducati? There are others, but those two spring immediately to mind.

Good luck,

Jezza

Yes,the V twin type springs can be installed in a single head. An acquaintance of mine has these installed in a 350 race head.

V twin springs will fit but you have to turn down the rocker a little so the spring doesn’t bind on the fatter single rocker shaft.
As the spring is compressed it locks on the fatter shaft and the force is then transferred to just the tail ends of the spring.
Try it and you will see what I mean.
They are soft and easy to machine in a lathe and I held mine with a bolt through the middle

Regards
Graeme

Hi all.
Thanks for all your responses, I am very tempted to do the clothes peg spring conversion, as it is not only seemingly quite easy but presumably removes a significant amount of spring loading from the opening rockers and cam surface while at the same time maintaining enough pressure on the split ring collets to stop any chatter or fretting (which is of course is the problem with not using springs at all). I take it any closer springs from a bevel V are suitable for this mod.......or should I be looking for springs from a particular model or year?? I have a feeling the previous owner has run this head without any springs and that is why these parts are missing, I am not in a mad rush with this so I will try a few more sources for std. spring retaining bits first and see how it goes.
Cheers,
Blethermaskite,
(george)

Hello George
I have several sets of original Desmo single spring sets that I done need if you can’t find any in the UK. (I’m in Australia)
Any of the early belt springs also fit.
I had some bevel springs copied at half the tension and used those. Any good spring making company can make them cheaply.
Lighter spring should be easier on the whole cam drive train, bevels and Oldham coupling than the originals

Graeme

I only used the rocker spring on the exhaust to aid starting, the inlet didn't need one, and didn't clatter.

Hi Graeme and Harvey,
Many thanks for your helpful replies and images, I have been very lucky, and with the help of Nigel Lacey have obtained most of the valve spring associated missing parts I needed, however I am still stuck for two of the top (desmo) valve spring retainers (or 'saddles' as I call them) so if anyone has a spare pair? I would be more than happy to buy, I thought there might be enough metal in the top spring retainers from a valve spring head to modify, .......but no.....it would probably be simpler to have a go at making new suitable desmo ones from scratch!
On a little productive note......just spent a very nice couple of hours in the workshop yesterday making a cylinder head assembly stand, which will stop me chasing a desmo head all round the bench while setting it up, and of course stop me holding it in the vice. Will post a photo later.
Cheers,
Blethermaskite,
(George)

Hi George

i got a pair of saddles last month from John Wittmann ( formerly Witty Ducati in Luton )

John is living in Spain but you can get a hold of him thru facebook .

Regards Eldert

Simple cylinder head jig for 250/350 heads valve spring or desmo, cost about the price of a cup of coffee and an hours work!