DesmoHarley – A Real Ducati Harley Davidson Merger

Harley Davidson V-twin with Ducati Desmodromic heads

Chris Barber, builder of the Alfabike, left a comment on our story about a potential Ducati - Harley merger with a link to his latest project and I think you'll like this. I guess he couldn't wait for the corporations to merge and, being one of those "can do" guys, decided to take matters into his own hands. Chris has created an engine, based on a Harley Davidson crankcase and cylinders but topped with a pair of Ducati heads, desmo valves and all. Of course, there's a slight difference in technology, pushrod valve actuation versus belt driven cams and desmodromic valves, but that's the whole point of projects like this, ... "what would happen if?"

He had a couple of cylinders made up to his specifications by Axtell with a different attachment setup. Instead of through studs as used on a standard Harley V-twin, these cylinders bolt directly to the cases with their own bolts, the heads will bolt to the cylinders separately since the Ducati heads have a different bolt pattern.

Chris also had to design and engineer the biggest piece of this whole endeavor, the gear drive for the belts to drive the cams. Once you get all of that together, you have a real shot at having an engine again.

Think of the possibilities. Purists on both sides of this are going to have fits. I love it!

Chris says he's almost done. Stay tuned!!

UPDATE: The DesmoHarley is complete!

More drawings and link below:

Harley Davidson V-twin with Ducati Desmodromic heads

Harley Davidson V-twin with Ducati Desmodromic heads

Link: Chris Barber's Desmo project

Comments

  1. Sean says

    The bastard child of the Italian mistress and the motorcycling Elvis. Cool. Wonder how it sounds?

  2. OTTOMAN says

    I, DON”T KNOW WHAT I LOVE MORE. THE TWO MOTORS COMBINED, OR THE FITS THAT BOTH SIDES WILL HAVE. CRISS BARBER HAS IT RIGHT GOOD LUCK…

  3. Clive M Sanders says

    Wow. And i was proud of myself for modifying my stock exhaust cans. Im trying to get my head around the technical advantages… neither pushrod nor desmo are especially reliable. I suppose with all the sportbikes with harley engines in them could benefit from a valve system that didnt skip at high rpms. And gobs of torque is always good.

  4. Keith says

    I knew if Harley Davidson and Ducati joined forces there soon would be a Ducati influence on the Harley v-twin . I love the look and sound of the push rod engine but with Ducati influence Harley/Ducati could have one freakin’ powerful cruser , after all isn’t Ducati building thr fastest v-twin out there ?

  5. sweetlemonaid says

    Customize a motorcycle–“common.” Modify a frame–harder. Transplant a nontypical engine–car (Alfas, Mazdas, BMWs, etc.) or airplane (radial or “jet”)–talented. Start modifying engines–a true craftsman–DesmoHarley (Desley)–Goldammer’s Trouble, and the most recent example–Stellan 8-Valve Hulster: http://www.bikernet.com/bikebarn/PageViewer.asp?PageID=1583.

  6. says

    Did you guys ever see the over head cam set ups that Arlen Ness put together. He used the stock HD heads but made a cam carrier out of the valve cover and ran a belt to each head from the original cam shaft. It was a cool looking set up. I don’t know how it compared to a stock motor but at the very least it was a true over head cam motor.

  7. jp says

    Adam: No lifters in this setup…checkout the modified HD cam gears driving the bottom desmo belt sprockets.

    This has got to sound interesting… 45deg. v-twins have a unique beat of their own and so do 90deg desmo twins. I can’t even imagine what that’ll sound like. As far as power, I’m sure it’ll be more than an equivalent pushrod setup as you don’t have to think about things like pushrod flex, valve float, and the like.

  8. RY says

    Those heads look like the 1000ds head. Are there plans for the dual spark and modern Ducati engine management systems for this ?

  9. Adam says

    I understand the absence of the lifters, but a nice feature of the Harley mills is the (hopefully) low maintenance – no valve adjustments. Suddenly the service intervals are a bit more often…

    Still it’s a heck of a hybrid, it’d be great to see it run in person.

  10. says

    RY – isn’t the DS head a ‘d’ual ‘s’park head ?

    It is hilarious to make purists “scoff”. This will put them over the edge (laughing as I write this)….now all we need is HD to make a unit-construction engine so it will be easier to stuff the big twin into a trellis frame like this:

    http://picasaweb.google.com/bigtwinsportbike/BigTwinWithTrellisFrame/photo#5077425125219414866

    I am serious about this type of chassis with a big “block” twin. I love the function & look of the trellis. Victory already makes a unit-construction engine with oh cams.

  11. RY says

    Hoyt,
    What I meant was I don’t see the 2nd spark plug hole in his drawing. I was wondering if it was like that on purpose or if the drawing is lacking that particular detail.

    I am a big fan of both the complexities of the Desmo L twin and the Briggs and Stratton simplicities of the Harley V twin. Most of all I have respect for the craftsmen that are not afraid to invent something that does not have an answer when you ask why.
    Chris , Excellent work.

  12. todd says

    I’m not sure what the rev ceiling is on the bottom end. I wonder if the pistons, rods, crank, or main bearings can handle the higher RPMs that the heads now allow. The DS motor revs to about 8000RPM. In the short stroke Ducati that comes out to a piston speed around 6000 feet per second, liveable if the components are of high quality. But the 4 1/4″ stroke of the HD bottom end and 7.44″ rods puts the pistons well into explosion territory around 9300 f/s. I doubt the engine will ever be used for high RPM work – mostly for show probably – so it should work great for that purpose.

    -todd

  13. Bob Horn says

    Todd,

    Your numbers don’t match the math I’ve been using to do piston speeds over the last 25~ years. Mine happen to closely match the ones generated by this site:
    http://www.wallaceracing.com/piston-speed.php

    Yes, it leaves off the rod length variable, but it is close enough.

    Not too long ago, piston speed redlines of around 3500 fpm were good for tens of thousands of reliable miles. 4500 fpm was considered by a lot of people to be the practical limit. Both those numbers would explain why my old FXRS had a stock redline set at 5200. The revised rpm using a new ignition box, cams, and valve springs was 6400 rpm. Above that, the big ends of the rods supposedly go oval.

    A handy constant for getting the magic “4500 fpm” number is to divide 27108 by the stroke in inches. I derived that number from the formula in A. Graham Bell’s excellent Two Stroke Tuning book.

    Oh yes – the 1000 Ducati engine with a 2.81″ stroke at 8000 rpm has a piston speed around 3700 fpm, nowhere close to 6000.

  14. P.T. Anderson says

    I think it’s cool cause the purists on both sides will have kittens. BUT what I really want to know is what it will be called? My vote is in for Harcati….. dohhhh

  15. marco samir says

    boas,sou um puro harlista,e nao gosto de ver outra partes de outra marcas relacionadas com a marca harley,seria um fracaso,e uma desilusao, para todos os quantos gostam da marca harley.

  16. beastinblack says

    If you want a short stroke twin get the thing in a triumph thruxton! That thing is screaming to be revved higher!