MotoScrubs.com

  Technical Information  
 

The following compilation of technical material is provided as a supplement to the resources still available to the Ducati single cylinder motorcycle owner.

 

The material presented here is specific to Ducati single-cylinder motorcycles. The information covers both narrow-case and wide case Ducati engines, and hopes to cover many single-cylinder Ducati models.

 

Motoscrubs.com and its contributors make efforts to ensure the accuracy of the information published on this website. However, the documents and web pages on this site may contain technical inaccuracies or typographical errors. All such documents and web pages are provided "as is.”  Motoscrubs.com and its contributors do not warrant the accuracy or reliability of the information presented within, and will not be liable for any errors, omissions, or any losses, injuries, or damages arising from its display or use.

Any information about products, services or merchants is provided for informational purposes only.
 

Ducati ® is a registered trademark and is owned by Ducati Motor Holding S.p.A.  Motoscrubs.com is not affiliated with Ducati S.p.A.

Parts Books and Manuals...
Thanks to a valued Forum member who digitized all the following books for this website.



The parts books and manuals are presented using the Cooliris© media browser. 

In order to achieve the full benefit of the Cooliris© Wall, right-click your mouse and choose "Full Screen" to facilitate parts book navigation.
 A large screen helps...

Ducati 250cc 5-speed Spare Parts Catalogue   ...available NOW.

Ducati D250-250M Spare Parts Catalogue   ...available NOW.

Ducati 160 Monza Jr Parts Catalogue   ...available NOW.

Ducati 250 Scrambler Spare Parts Catalogue   ...available NOW.

Ducati Wide Case Parts Catalogue   ...available NOW.

Ducati OHC Workshop Manual   ...available NOW.
 Ducati OHC Workshop Manual ...in PDF Format

Ducati 450 Group and Lists Parts Supplement   ...available NOW.

450 Owner's Manual ...in PDF format
 350 Scrambler Owner's manual ...in PDF Format
 Scrambler 250 Monza 250 Owner's manual ...in PDF Format
 

         Diana Brochure

 Ducati Singles Engines...

 

Blueprint for Power Herb Hitch and Jim Hayes Junior's performance modifications for the 250 narrowcase engine.

Narrowcase 250 Engine housing bearings chart

Instructions for Use and Maintenance of the [Ducati] 250cc OHC Racing Motorcycles
Presumably written for the 250SC (narrowcase) racing engine, but of unknown origin.
How to Build a Vintage Ducati Racing Single
Engine, carbs, frame + more. Outstanding reference site - build-you-own rear sets, brake stays, etc.
How to Repair a Slipping Narrowcase Kick Start Lever
Been there, done it...

Crank End float comments from Bevel Head DSM:

I've been working on the Mach 1 engine. I managed to find FAG German made 'old stock' bearings (except for one) by shopping around. The old bearings came out at about 250 deg F in the convection oven save one which needed some persuasion.  After cooling, I cleaned the bearing bores carefully & reheated. The frozen bearings dropped in easily, but I found the difficult one to come out did not spin easily when cool. It appears the greater 'interference fit' on this one was also compressing the bearing and pushing the outer and inner races closer. When the case was hot it spun freely, but when cold it was binding. I had another bearing which worked. It is possible the bore was not as clean as it should of been.

I made a case mounted bracket for my dial gauge for the end float measurement, then put some rubber fuel line on my big screwdriver and was able to gently lever the crank via the cylinder hole (the rubber bearing on the aluminum case). The calculation did not work the first time, and I had to increase shim thickness a few times. The gasket measures about .010" I've got some worries that when I torque all the screws down to spec, it will compress a bit. So far, I have just snugged down the screws. The crank turns freely but zero float.

It did occur to me that since Ducati specs the end float at .001" to .002" (the standard main bearings are not made for axial loads). the end float will be taken out when the lower bevel gears are shimmed and meshed...which may not be too good for them! Any backlash at all in the gears (there has to be a little) will allow crank axial movement. I'm wondering if an improvement could be made by using 15 degree angular bearings like the twin motors. Then end float will never exist if the proper preload is applied...or at least not until a lot of bearing wear.

Frank Scurria added this:

--- On Thu, 1/7/10, dsm wrote:
 The calculation did not work the first time, and I had to increase shim thickness a few times.  The gasket measures about .010" I've got some worries that when I torque all the screws down to spec, it will compress a bit.  So far, I have just snugged down the screws. The crank turns freely but zero float.
*************
That's what I prefer---zero end float, but with the gasket compressed (which it will do).  Put a light smear of oil on the cases so the gasket won't stick and tighten the fasteners the way they will be when the engine is running.  Please don't use any silicone sealer.  In my opinion, it has no place on a Ducati.  If a "hatchet mechanic" has previously levered the cases apart with a screwdriver, and marked the cases and some type of sealer is needed, I recommend Hylomar, or Wurth (Hylomar made in Germany).
*************************************
It did occur to me that since Ducati specs the end float at .001" to .002" (the standard main bearings are not made for axial loads). the end float will be taken out when the lower bevel gears are shimmed and meshed...which may not be too good for them!
**************
Definitely do not use bevel gear shimming to take out crankshaft end float.  Set crank end float first.  That must be done separately.  Then the bevels.
****************************************
Any backlash at all in the gears (there has to be a little) will allow crank axial movement. I'm wondering if an improvement could be made by using 15 degree angular bearings like the twin motors.  Then end float will never exist if the proper preload is applied...or at least not until a lot of bearing wear.
 **************
I never tried that.  I don't see the advantage.

Frank
 

Ducati Engine torque values from Master Mechanic/Author Tom Bailey:

Torque specification is described in the workshop manual as --"Tight".. (Smile) I note that in attending 4 Berliner Ducati schools, all of which were about as half ass as the one described in the book, at no point were torque specifications ever discussed. Further in observing mechanics both at our shop and at the races, I never saw anyone using a torque wrench in the assembly of a Ducati engine, nor did I ever use one...

Interesting in that torque wrenches were religiously used in the assembly of English engines...

I do not think the stretch factor ( which is the reason torque specs are usually given) is critical with regards to joining Ducati cases. The 2 M8 bolts are there to stabilize the case for the cylinder head bolts and the M6 allen heads are there to provide oil tightness. You would think the cylinder head bolts would be somewhat critical and have a torque rating but they are likewise specified as "Tight". Perhaps the aluminum construction of all the pieces (save the cylinder) provides enough expansion that it is not a problem...

Torque ratings on M8 8.0 bolts (as used on the 160 - 350 narrow cases) are in the area of 17 to 18 ft. pounds. I would think 10 percent less would be adequate... Torque ratings on M8 10.0 bolts ( Widecase engines) are in the area of 25 ft. lbs. - Again at least 10 percent less if I were doing it with a
torque wrench...

Stainless steel bolts (often used in modern restos) are weaker than high carbon steel and available in a wide variety of different alloys of different strengths. To find a torque spec for those you weed need to know the alloy...

As far as the M6 allen heads -- use a two inch long allen wrench and do not overdo it. Strip the treads on the bottom of the oil pan and oil will leak out the screw hole! We always coated the center gasket with olive oil. When beads of oil oozed out of the center seam we figured it was tight.

One thing you do NOT want to do is use the screws and bolts to bring the cases together - this will warp the cases. With a wood mallet and a soft wood rod tap the cases until they are in contact, then put the screws in... Use an X pattern for tightening the allen heads. Put the M8's in last.

In other words -- I don't know...and I continue learning that I don't know more everyday.

Ducati Service Bulletin

The following service bulletins are thanks to Ventodue:
 

 

And some more service bulletins donated:

 Ducati Singles Carburetion...
 

Dell'Orto SSI Manual

Dell'Orto SSI exploded parts list & diagram

Common Dell'Orto jetting for singles

Dell'Orto PH & VH series float settings

Ducati Singles Exhausts...

Download a PDF blueprint of the Mach1/Mark3/Diana megaphone...

Download a fully rotating 3D drawing* of the Mach1/Mark3/Diana megaphone...

* Requires Solid Works' free eDrawings viewer available at:
http://www.edrawingsviewer.com/pages/programs/download/index.html

Ducati Singles Electrics...

Electrical Systems (magneto) Booklet Electrical Equipment Operation Booklet  Ignition and Flywheel Specifications Booklet 

Narrowcase Electrical Systems (magneto) Booklet  with schematic

Narrowcase "Magneto" Schematic with diagnostic information (requires PDF reader to view)

Narrowcase "Alternator" Schematic

Narrowcase "Regulator" Schematic {a component of the Alternator system}

Narrowcase Electrical Equipment Operation Booklet  with schematic

Narrowcase Ignition and Flywheel Specifications Booklet  with static timing information

Narrowcase Regulator teardown, inspection and repair

Ducati Service Bulletin

Ducati Service Bulletin

Ducati Service Bulletin

Ducati Service Bulletin

Ducati Service Bulletin

  • Headlight Removal
    (To run without the battery or headlight on 250 & 350 SCRs with Magneto ignition)
     

Ducati Service Bulletin

 

 
Ducati Singles Forks
  • Narrowcase (31.5mm) Fork rebuild article
  • Narrowcase Forks have a manufacturing date code stamped in the brake boss.
    • A fork assembly's date code  may help to establish the year the motorcycle was built. 
      Ex: June 1965 appears as "6  65"
    • In North America most Ducatis were sold and assigned a model year at the "point of sale" such that every motorcycle a dealer had was sold as a current model year. The headstock placards were rarely stamped with the complete model year.
      Ex: Anno Di Costruz (Year Of Construction) is stamped with an open-ended year; "196 "
  • Widecase Forks

 
Ducati Singles Wheels
  • Rear Wheel bearings
    • The wheel requires two #6202 2RS bearings with shields.
    • The cush drive requires two #6004  2RS bearings with shields.

 
Misc.

 

Cu Layer Inc.  © 2004 Cu Layer Inc.