How to Restore a 1966 250 Ducati
 

Living with a 1966 250 Ducati

Gears and ratios

Cruising at 60 km/h, the tach shows around 4000 rpm, sounds nice but a little fast.  I have noticed that when I get aggressive with the throttle at a light, the front end gets light!  The bike was set up with a 16 front and 46 rear.  This gave me a ratio of 2.88.  I made a spreadsheet in excel and put in the different combinations of easily available front and rear sprockets.  I set up the spreadsheet to show the delta rpm from 60 km/h.  For example 16/46 multiplied by 1392 gives me roughly the rpm at 60 km/h.  If I changed the ratio to 17/46, the rpm drops 235 rpm.  This sounded reasonable for the first reduction.  It was difficult finding a new front 17 tooth sprocket.  I got one from Phil at Road and Race and I got another from Steve at Bevelheaven.  The rear 43 sprocket came from Syd's.

 

Front

Rear

Ratio

N

RPM 60 km/h

RPM delta

17

43

2.53

1392

3521

-481

16

43

2.69

1392

3741

-261

17

46

2.71

1392

3767

-235

16

46

2.88

1392

4002

 

 

Clutch cable

I was coming back from a ride when my clutch cable let go, again!  This was the third time and fortunately I was just turning down my street so I didn't have far to push.  I knew what had happened and as I took off the shifter box, the cable had pulled through the cable stop. Again!  I bought new cable stops from Flanders and torqued the heck out of the bolts but the cable still slipped.  It also made a mess of the cable.  I took 2 cable stops and silver soldered them together.  I installed the new stop and haven't had any problems since.

Clip-ons

Driving with clip-ons has been literally torture!.  The way the bike is set up means most of the weight is on the wrists.  Driving with clip-ons means that your body is bent low and you have to look up to see ahead.  The spine pad on my Joe Rocket pushes the back of my helmet up which in turn pushes my glasses down.  Constantly adjusting my glasses and the pain in the wrists from the driving position means very short, frustrating driving times.  I notice that when going fast, the air takes the weight off of my wrists like it is supposed to but I drive mainly in the city and I can't really cruise through the city at 100 km/h.....

The clip-ons had to go.  I got a normal top triple tree and installed flat bars.  Fitting the top triple clamp was another headache.  As I have tapered head bearings, the races are larger in diameter than the stock bearing races.  That means that the aft nuts for the U-bolts that attach the handle bars to the top triple clamp are in the same place as the upper bearing race!  I ended up cutting off the aft part of the U-bolts and tightening the heck out of the fwd nuts of the U-bolts.  Believe it or not this worked and I tried lifting the bike a number of times by the bars and they don't move.  I still added a titanium bolt that goes from the bottom of the triple tree into the handle bar to be safe.  After a season of riding, I have not had to adjust or tighten this set up.  I can drive the bike for as long as my butt lasts, the seat foam is too hard.

Rocker shift lever

The rocker shifter lever lasted about 1 hour, it was just too weird for me.  I removed the shifter box and redid that mysterious adjustment and shifting has been a lot better.  I think there are only 3 or 4 extra neutrals now!  I still find that when in traffic and with the clutch getting hot, spontaneous neutrals pop up all over the place.  When down shifting to a stop, I can find neutral most of the time but finding 1st from neutral usually requires 2 jabs at the lever.  I really need to adjust the lever to get a better shift angle.  The serration's on the shaft are too coarse.  I am going to try my rocker set up only with a normal shift lever.  That should allow a much finer adjustment of the shift lever.

Gas cap

The gas cap that came with the bike was basically a fiberglass cap molded around a metal cap.  It was too low and was really tough to undo as you could only use the tips of the fingers.  I cross threaded it a number of times.  I found a someone who actually molds all kinds of really hard to get rubber and bakelite parts for the Ducati.  The best thing is the stuff is new, not old cross linked old rubber.  I found the cap at Bevel Rubber.com

I bust up the old fiberglass cap and bonded the metal cap into the new bakelite cap.  It is about a 1/4" higher and is easy to grip and looks fabulous and is hard to photograph as it is black......







Storage

Rather than dragging the bike down into the basement, I decided to cocoon the bike in one of those big plastic bags.  I have access to large amounts of desiccant as the prepreg that is used where I work comes with a big bag of desiccant to keep the prepreg dry when it is removed from the freezers.  I had to fight the old ladies for a bunch as they use it for drying flowers.  I got about 10 lbs and loaded the bike and the desiccant into the big bag.  A vacuum sucked the air out and I tied the end shut.  Springtime will reveal just how well the bag worked.  I don't think I will do it again as I like to work on the bike during the winter.



High clutch lever pull 

I overhauled the clutch, making sure that the plates are flat.  I replaced the heavy duty springs with normal springs.  BTW, I don’t get any clutch slippage with the normal springs.  Cleaned and greased the clutch rod operating rods (see below) and tried both ways.  Cleaned out and regreased the clutch operating rod passage.  Rerouted the clutch cable in all kinds of different ways.  Oiled the lever pivot and cable and greased the arm pivot.  Replace the pivot pin and arm with NOS parts.  And it is still one of the heaviest clutch pulls I have ever experienced and I have ridden Laverdas.  The only thing that seems to reliably help is the Gripmaster.....






Clutch operating rods

Which is the right way?  Top is from a Ducati parts manual and the bottom one is from Clymer.



Problems with the selector box or 5 speeds and 7 neutrals

A very common problem is getting the transmission to shift properly.  The severity of this problem varies from annoying to absolutely infuriating! 
There is this thing called a selector box which can be finicky to set up and if not perfect can result in a traffic pile up as the owner desperately and
frantically is trying to stomp the gear lever into 1st gear from neutral.  Even better is winding the bike out only to see 10,500 rpm on the tach because
for some reason there is now a neutral between 3rd and 4th. 

I made a summary of all the comments from various single owners from Bevelheads.  I didn't cite anyone but you know who you are.....

http://www.mts.net/~jkrocker/Duke3.90/Box of neutrals.doc


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