UK Ducati 250 mk3

[Scottish888]

Hi Folks,

starting to work on my recent purchase of a Ducati 250 mk3 (1974)
It was last used in 1991 and laid up since then, last few years in open shed but the frame and paint stood up well, quite impressive.
The engine kicks over...too easily, what should I suspect first? Never worked on a Ducati single before so will be cautious.
It does sound a little noisy at the top end when kicking over quickly, like tappets too much clearence?
The previous owner said it run fine before laying up.

Thanks

[Samurai]

Hi good find if the price was right!

Personally, I'd do a full engine strip and see what you've got. Of course the previous owner will say it was running fine, but if it was, you have to ask yourself why has it been sat since the early 1990s!?

Could be any one of a number of things making the noise, from worn bevel gears to tappets or starter mechanism. I'd want to check before firing it up and possibly causing more harm.

They are pretty simple engines to take apart of you have a few specialist tools and the time. Parts are freely available (but not 'free'!), so that shouldn't be a problem.

Good luck and keep us posted on your progress!

[Jordan]

Samurai's advice is good in a general sense, but to be more specific I'd add that a Ducati engine is easy to work on the top end, but gets more complicated when working within the crankcases.
Your description suggests lack of compression, the likely cause of which is within the cylinder head.
It could be simply that it was in storage with a valve in the open position, such that corrosion on the valve/seat prevents proper valve sealing.
Removing the head is a delight. Remove fuel tank, exhaust system and carburettor. Then remove the four long cylinder/head bolts, after which the head can be lifted out for inspection.
If you have never heard this engine running, consider that it may not have been timed correctly, with regard to the marks on various gears between the crank and camshafts. So, careful retiming may be needed.

[Bevel bob]

Before taking the head off ,line up the marks as per the manual and dont rotate the motor if you want to keep things really simple, The marks may be wrong of course!!.

[Scottish888]

Thanks folks,

does anyone know where I could find a manual online? or is the haynes manual ok?
I have the engine out at the moment as I had to strip the bike to get it in the car.
I don't know much about these engines but I believe there are two types? any information would be appreciated.
I am not sure if my bike is 6 or 12 volt, I guess it is a points ignition system, still got a lot to check out

[Jordan]

There may be a free manual at ducatimeccanica.com or bevelheaven.com
The Clymer manual is a reprint of factory material.

[Bevel bob]

If its a 74 Mk 3 it will be a widecase (stronger ) motor and the cycle parts will also be different to the narrowcase much earlier bikes.

[Scottish888]

Thanks,

Does anyone know when Ducati mk3 production ended?
I heard there were Spanish produced Ducati's, how can you tell if you have a Spanish or Italian bike?
My bike has been in the UK since new, not a recent import.
I am enjoying cleaning it up, I will renovate it rather than restore it, try to keep it in good survivor condition.
The fork stanchions may have to be replaced as they have some pitted corrosion in a couple of areas, I may try to save by using epoxy, also the clip on headlight brackets have corroded through, not sure I could weld new section in as it was/is a thin bracket

[ducwiz]

Hi,

the Haynes manual is a good starter for the late w/c singles. It deals also with both electronic ignition systems (Ducati and Motoplat); one of these should be present in a 1974 model (no points). The original alternator/battery system was 12V, but can easily converted to 12 V with a cheap chinese scooter R-R.
More technical info you might find here, for download: http://www.luke3d.org/bmw/manuali_ducati.htm

I agree with others here: disassemble the engine completely and check for wear, excess and play of any shaft, correct alignment of bevel gears, etc. The sludge trap in the crankshaft should be opened and cleaned out, the oilways then must be flushed intensely. Inspect and measure piston and cylinder bore, and take off the valves from their guides. Stem seals might have become hard and brittle, should be renewed; also the guides might be worn.

Epoxy on the fork stanchions is a no-go. Let a specialist inspect the rust pits. If servicable, get them de-chromed, ground to the needed surface quality and hard-chromed to measure again. Or buy new stanchions.

You need a couple of specialized tools, like alternator flywheel extractor, clutch basket holder, camshaft blocking tool, extractor for lower bevel shaft bushing, etc. These tools are shown in the spares list and user manual.
Study the manuals and the parts list, from which you will learn a lot.

cheers Hans

[Scottish888]

Thank you Hans,
I will follow your (and others) advice on the engine.
I can actually turn it over by hand with the plug in.
It still has a pink Lodge spak plug in it.
The ignition has a Ducati electronic system, delighted, not many manufacturers were fitting electronic ignition in 1974, even car manufacturers!
So happy with this bike, hopefully the engine will be better than I worry about, it was running and on the road before storage.