1963 Ducati Diana 250 Mark III completion

A 1963 (1964?) Ducati Diana Mark III 250 came through the shop a while back. It was partially restored, and needed to have the last bit of the job done. The bike was owned at one point by Jason Small, who also painted it. During the research and restoration, some of the information suggested it was a Mark III model, a US version imported by Berliner with a competition set-up. With that in mind, it was modeled as closely to the specs of the original, with the exception of the muffler.

Classic Ducati styling from a great era of motorcycle styling and building. Touted as a ready to race factory model, The Mark III was stripped down, and fitted with performance parts. A larger competition type Dell Orto carb and velocity stack, twin tank petcock feeds, free flowing exhaust,  and other mods produced a reported 30 horsepower from the 250cc engine! The competition tachometer, clip-on handlebars, passenger peg delete, and battery-less ignition rounded out the package. Items found on other Diana models like side covers, air, tool, and battery boxes were also stripped off to save weight.

Even the tail light was kept small to minimize weight, but still satisfy racing categories that require stock unmodified bikes.

The front number plate/windscreen showed up in the Berliner advertisements, but it is unclear if this was a factory part. This one was made from aluminum and Lexan, and modeled from the Berliner brochure images.

The bike as I found it. Paint had been done, but a bunch of parts were missing, and the everything needed cleaning and detailing.

The engine was loosely bolted in, and in need of some work, but was said to be in running condition prior to tear-down.

After replacing and re-plating hardware, some cleaning and polishing and a bunch of new parts, the beauty of this Ducati design shines through.

A badly worn seat came with the bike, but did not fit properly, and did not resemble the original seat. 

While similar to the Mark III seat, the front mounting bracket needed modification to fit with the tank and frame. The seat had been re-covered at some point, and a number of extra holes drilled into the side bars of the seat frame, to mount rivets.

The design of the original seat is unusual in that it has a thin layer of foam sewed into the seat cover, and laid over a spring frame. The original foam was falling to pieces, so a duplicate was made from high density close cell foam. In this picture, the seat assembly was getting ready to go to the upholstery shop ( Xtreme Upholstery in Denton, TX,) where the seat cover was made and sewed through the foam. The other detail that had to be worked out was the pointed tail of the seat. Since there was no original seat to model from, it was based on pictures from brochures and other bikes. A close-cell foam form was made and placed at the rear, but the fact that the rear panel on the seat is not supported by any frame at the bottom, it floats somewhat, and was difficult to support. I was very happy with the final result.

After the seat frame was modified, the holes were welded up on the side rails, and it was painted. Andy at Xtreme Upholstery did a phenomenal job on the cover, even adding the canvas underside. I added the special front mounting tabs, seat strap and badge, and the mounting side rivets to finish it off.

On display at its final destination.

A failed tank liner was stripped from the tank, and it was re-lined with POR-15

A photo prior to the front number plate and correct hand grips being placed on the bike.

The beautiful Dell Orto SS1 27mm carb and velocity stack. Everything was polite, re-plated, and missing parts replaced.

The original Berliner spec sheet. The five-speed gearbox on this bike suggests it could be a 1964 model, as the four speed was a four-speed. The serial number, however, suggest a late 1963.

The speedo is from another model, and only goes to 80MPH. The original one is hard to find, and goes up to 110MPH. Once again, the Ducati styling of this era was just classically beautiful.

Finishing the 1974 Honda CT70 Dax "Dino" custom.

She’s a runner! The first few miles have been logged to test the brakes, steering and suspension, and everything feels right. The bike starts easy, idles well, and runs strong. There was a great deal of difficulty getting the engine to start initially, but once figured, it has run like a champ. The bike color looks black in the overcast sky we had for the pictures.

All systems are go…and stop. The front disc brake grabs nicely, and the left hand brake for the rear works well with the pedal. The brake light is hooked to all three actuators. The amber headlight and tail light are turned on with the key switch in the third position, and engine is running. The bike idled patiently while the picture were taken.

The LED tail light was made to echo the rectangular headlight. The green neutral light can be seen glowing on the speedometer.

Even though the exhaust looks similar to the original, the heat shield was arched to make it thinner, and the canister was formed to match. The shield was also turned around and given a hidden hook bracket to secure the rear portion tight to the canister.

With the long swingarm, the lowered shock mounts and shortened front fork tubes were necessary to keep the stance right.

The Dino with the CT117, the inspiration for this build. Built thirteen years apart, the Dino has a lot more hand formed parts.

Just showing some of the similarities in the designing for these bikes. A forward facing scoop on the CT117 was one of the signature features…

…the Dino scoop is also forward facing. In the case of both designs, I can find no other similar examples online. This scoop attaches to the stock air box.

Another unique feature was the rear hinge on the seat, and the gas cap poking through the front.

A similar aluminum sconce fits around the Dino gas cap, and uses the same front thumb screws to secure the seat.

The source of a great deal of grief. When I went to start the engine, it would only run at high RPM, and carburetor adjustments, jet changes, and an entirely new carb had little effect on the running. After several weeks waiting on the carb parts, checking the wiring, coil, and engine valve timing and clearances, searching for intake air leaks, fuel starvation, and a load of other stuff, I finally remembered a similar engine starting problem. It reminded me of a similar problem getting the Cabracer 360 bike started. In that case, an aftermarket ignition set-up was misaligned, and scored the rotor. A quick check under the flywheel showed a score line on the flywheel. In the case of both engines, they would fire intermittently, but could only be kept running at high RPM, and were transformed to normal starting and running with new flywheels. This engine has a 12 Volt conversion with CDI ignition, which uses the magnet position to sense flywheel location., as was the one on the Cabracer 360 engine. My theory is that the score line produces a slight bit of magnetism in the aluminum portions of the flywheel, and confuses the sensing enough it cannot run right.

Detailing out the 1974 CT70 Dax Custom

A million details. Going down the checklist of each job, working out the electrical, mechanical, and cosmetic details. Most everything is done, aside from starting and tuning the bike.

Always interesting to see the color scheme playing out. Trying to find the right balance between chrome, black, wild cherry, and gold colors was challenging. There is part of me that would like to see the gold stripe on the fairing and tail section, but it might make things a little too busy.

Always close to the end, the badging has to be done. There are two locations on the sides of the bikes, where the original foil sticks went, that are perfect for some badges, This is on the right side, largely concealed behind the muffler. The logo at the top was made like the badges on the CT117, piercing the metal plate to make the letters. The rest was done with simple letter stamps. A more refined one was made for the other side.

This badge was done by Master Engaver, Wade Oliver Wilson of Mansfield, Texas. He has done engraving for quite a few of my builds, and always knocks the ball out of the park. The “Dino” script is from the Ferrari model by the same name, but meant as a nod to the owner of the bike who goes by Dino. The purple paint matching Dino the Dinosaur’s color was a coincidence, but it works!

A scoop on the side of the stock airbox was a last-minute addition. Using another component reminiscent of the CT117 build was part of the reasoning, but the truth is I have been thinking about this mod for years, just didn’t have the right bike to try it out till now. The CT70 is a challenging bike to customize, in my opinion, because of the unique frame, swingarm, and oversize tires.There are clearances with the chain, rear fender and wheel that do not allow too much variation.

Prior to going to the chrome shop. The scoop fits tightly with the screw from the center of the airbox, and the bracket that goes to the usual airbox mount.

The design of the scoop was influenced by the curves of the frame. Though the angle of the scoop opening looks a little sharp and angular, it appears to be more vertical from the front.

A brass insert with mesh filter was added to complete the design. It is a friction fit and can be removed easily. once again, a little more of the gold color to accent some of the darkness.

Another detail from the CT117, the filler neck of the tank, poking through the seat.

Just needing the front fairing to be complete up front.

Some of the more mundane parts of the build, the rubber packing in the original carb needed to be replaced. This is a common place for leakage. Glad to catch it now. The rest of the carb was cleaned with ultrasound and vapor honing.

Another detail that needed attention was the battery box. With the engine’s electrical system being changed over to 12 Volt, a larger battery was needed. The closest size was slightly too large, so the box was bent and cut to accommodate the larger size, plus some cushioning.

The corners of the box were rounded off on an anvil, making it wider, side to side, and longer on the bottom. The mounting brackets were also re-formed to make the wider box fit inside the frame. The overall effect was to lower the battery 3/4”, to clear the seat pan.

The first look at the seat cover. Still some fine tuning to get it just right, but liking the overall look. The gray color is an optical illusion from the lighting. It is actually a traditional black.

The shot from above shows the smooth transition between the body and seat lines.