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DesmoHarley – Italian American V-Twin Completed

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DesmoHarley engine - Ducati/Harley Davidson by Chris Barber

Chris Barber sent in a few photos of the now completed DesmoHarley, his own unique Harley Davidson engine with Ducati heads, and it is a beauty. A few weeks ago when we introduced you to his project, the drawings were all we could see. Since that time Chris put it all together and it’s the kind of thing that gets a motorhead all twitchy just looking at it!

Here are the specs:
Displacement:
80 cubic inches/1340cc
Compression ratio:
10.3:1
Carburetors:
2X38mm flatslide Mikuni
Pistons:
Keith Black flat top (8.5:1 in a stock 80 inch Harley)

Chris says:

The heads are the early large valve 900ss type, both the heads are rear heads with the front turned around 180 degrees and running a front head cam, this gives me two heads with horizontal fins and orients the carbs and exhausts in better positions for the 45 degree layout.

I didn’t need to do any head work to get a 10.3:1 ratio because the Ducati has a fairly low ratio with domed pistons, so by going with flat top pistons with the extra displacement, the ratio worked out perfectly.

Chris had to engineer his own gear drive system for the cams and it came out great. Specially made Axtell cylinders have their own bolts to attach to the cases plus bolt holes in the correct pattern for the Ducati heads.

Since Chris had earlier put an Alfa Romeo V6 in a Harley frame for his Alfabike, I can’t wait to see where this engine ends up. Excellent work, Chris!

See larger photos below:

DesmoHarley engine - Ducati/Harley Davidson by Chris Barber

DesmoHarley engine - Ducati/Harley Davidson by Chris Barber

DesmoHarley engine gear drive closeup - Ducati/Harley Davidson by Chris Barber

Posted on Filed Under: Engines, Motorcycle Builders, Popular

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Comments

  1. Chris. If you ever have an iterest in putting one of your engines in a sport bike please let me know. This would make an awesome engine for a Big Twin Racer. Best of luck.

  4. WOW !!!!!!!!!!!!!!!!!!!

    I mean really WOW !!!!!!!!!!!!!!!!!!!!!!

    You just blew my mind.

  5. That’s farking awesome. *thumbsup*

    This duc-riding rocket scientist is drooling. Engines are neat!

  6. That is pretty sweet looking. I am ofc, wondering 2 things… what does it sound like running and what kind of HP will it get???

  7. Chris… got another project for you… Design a new case for your HD/Duc engine that uses a cartridge style transmission!

  8. here’s my thought progression when I first saw it.

    -ugly, and kinda stupid.
    -well, it gets bonus points for pointless complexity.
    -he really did pick the best looking bits to mix and match, I suppose.
    -wow, he even kept the exhaust layout reasonable.
    -it doesn’t look like a frankenstein, I could see this being a production motor.
    -Imagine what it must sound like!
    -I wonder if he can solve the monsterous clutch/primary problem?
    -that’s the coolest thing I’ve seen for a while!
    -I wonder if the rest of the bike has this kind of work put into it?

    Thumbs up!

  9. I’d like to know what the target RPM is for this set-up. Other than the more ideal flow of the intake tracts how would this be any better than Harley based heads? Wouldn’t you get even better torque and HP results if you went with a 4 valve head?

    Strictly speaking of undertaking a project like this, great job.

    -todd

  10. The main question to everyone is who would not want to try it in their cycle? You look around on the Kneeslider, and do not lust to try a couple of the wild inventions, or desire to own a few? It is just a Curt points out–Go For It!

  11. Nice work, I think it needs an acronym though; how about:
    Mostly American, Fantastic Italian Addition

    I wonder if you could build a version ‘legal’ for AMA production racing? You know, the formula which allows 1200cc pushrod engines in against 600 IL4’s. How about putting the Desmodronic cam/follower setup in the bottom of the engine then run push(and pull) rods to the heads, and then reverse it all…
    Short stroke, should be good for 10,000 RPM?

  12. ” yo, Adrian !”

    no, this is much better than that Italian-American…but “Balboa” has a good ring to it for the name of a motor instead of all the alpha-numeric stale names.

    Aaron – your experience is the sign of any good design….you’re made to face it & dig it.

  13. I’m stunned at how awesome this is. I mean, who takes two such dissimilar engine components and puts them together? I’m thoroughly impressed.

  14. As for picking the name for this beautiful frankenmotor I’d like to throw “Harcati” into the hat. This is the kind of stuff that keeps me coming back to see what’s here. Thanks again to Paul Crowe for putting this site together and a big thanks to the guys like Chris Barber for putting stuff like this together. Bravo!

  15. Thanks everybody, you all are a very nice bunch

    I know the engine will still have limitations, inherent with the long stroke 45 degree but doing this stuff keeps me out of trouble.

    Thanks to Paul for posting it up here.

  16. for the next project – a motor that would really blow my mind would be an old mv agusta to converted to desmo! throw in a magni chain drive conversion and get it around 400 lbs…….(insert homer drooling noise)

  18. I think the perfect place for that engine would be on a Morgan trike replica. American v-twin,Italian heads in a British car, with everything hanging right out in the open on the front of the car.

    rr

  24. Chris, Brilliant !!!!!!!!!!!!!!!!!!!! Now can you fit a commando head to a bonnie ? Anyone ever tried ? HaHaHa. This was what Lennon’s song ” Imagine” was really about ! True, he told me.

  28. While I can respect the enginuity that went into this, it seems a rather pointless exercise to merge a top end off a 9,000 rpm short stroke motor with a long stroke 6200 rpm bottom end. Looking at the bottom line, there’s seemingly little to gain from it.

  29. Questions no one else has already asked: How were bearing/lubrication system incompatibilities handled (if any, I’ve no idea what the specs are for the Ducati heads, and I’m assuming the HD bottom end is similar to the roller bearing/16 psi Sportster designs)? And (following up on Rick A) are the cams stock in the application for the heads, or some other design? Looking forward to seeing the dyno results!

  33. Leave it to a guy like Rick A to get all Spock- like on the cool Duc-Davidson .Why do it? Because he can !

  34. Nice build.

    A lot of straight cut gears up to the mid shafts running the belts for the cams, that must be a bit noisy? I was wondering about using a similar setup on a sportster type engine, for a buell or similar, would be easier to use in a sporty chassi and the sportster bottom end is very strong.

  37. While walking thru the Dali Museum a person is found to always be saying WOW.. now we can say the same thing here.
    The only question left is…Can I have one. Pretty Please with a cherry on top.

  38. Very cool build.

    However….the heart of the desmo design is the ABSCENCE of belts or push rods!! This is just a OHC of a different color….NOT a Duke.

  39. What makes a valve train a desmodromic design is the absence of valve springs to close the valves. The Ducati desmos have a rocker that opens and closes the valve ‘positively’, not depending on the tension of a valve spring to keep the valve following a cam profile. The Ducati system also had a small torsion spring to press the valves against the seats to give the motor enough compression to start and idle, as the rocker-valve assembly was clearanced a few thousandths to allow for expansion and a lubricating oil film. It is really the combustion gases that hold the valves pressed against the seats at higher engine speeds. The elimination of valve springs was significant in the 50’s and 60’s when it was the weakest part of most valve trains in high RPM engines.

  40. Just a additional thought… Ducati themselves have made both shaft and bevel gear driven camshaft desmo designs like the 900SS, and belt driven camshaft desmo designs like the Pantah. Desmo engines come and go out of favor cyclically; the last desmo engine I can recall was in a recent Honda F1 (4 wheel) engine prototype where the desmo arraignment was replaced with a nitrogen gas pressure air-spring to close the valves because the reliability and simplicity proved superior in testing. Valve spring metallurgy, computer designed cam profiles, and the use of high-speed interferometry to observe all the pieces in motion make the problem that desmo valve trains were designed to solve a moot point.

  41. Outstanding! Remarkable and fine. I suggest going to a 4×4 bore and stroke then cart (or ride) it to the salt flats or the eastern equivalent (and only a few miles away).I would hazard a guess of 220+ hp would be available without power adders, and the hi rpm would not need be sustained for long. Can you say 230 partially streamlined mph?

  42. Fantastic engineering project ! It’s great to see someone who can actualy make something unique instead of the usual throng of talking heads and couch critic’s,who produce nothing but hot air and bullshit. Keep up the ingenious work.

  44. Double D
    Ducati-Davidson,
    Very cool, just because you can & did, put it in a feather bed frame…….

  48. I just recently stumbled across TheKneeslider and I am amazed at the all the great examples of ingenuity by creative individuals featured on this site! This is one of my faves! I wonder if Chris Barber has ever met Gregg of Greggs Customs? Or now that he’s moved back to the U.K., I’d love to see the result of installing Chris’s engine in one of those beautiful Spondon chassis kits.

  49. Gives new meaning to America being a melting pot-but I don’t think this is what they had in mind!If they start it up I hope they send an audio file so we can all listen to it. I thought Ducati’s had a lot of gears…

  51. Maybe I’m missing something here but it seems as though this engine left out the best attribute of the Ducati V-Twin: the self-balancing nature of the 90 degree cylinder angle. For a street engine I’d expect a 90 degree harley would be a bigger improvement than the 2v desmo heads.

  52. Great engineering excercise, but isn’t one of the plusses of the pushrod Harley motor, it,s low height? The higher RPM allowed by the Desmo heads would also be a bit negated by the heavy Harley crank assembly-so it’s only a Harley lower half because of it’s 45deg cylinder angle.

  53. Short life HD engine mixed with the italian quality. LOL
    At 10,000 rpm it will blow out, if he can fire the engine.

  55. Nice stuff that keeps me coming back to see what’s here. all the great examples of ingenuity by creative individuals featured on this site! Thanks

  57. Hi
    Great looking pics and specs of the engine,
    is it avaliable on commercial basis?
    waiting for your feedback
    Ayres

  59. I love it!! and I believe what mike was getting at was directed to jack, the 45 degree does produce worse engine balance but a better performance (as in ignition timing) the ideal for a two cylinder four stroke being once every 360 degrees as in a inline but being smoother at 90 degrees this man just took the best of both worlds, comfort (coming from the heavy flywheel of the H-D mill) and speed, but i wonder (always have) why is it that ducati make’s a 90 degree engine (typically worse for performance better for comfort) and harley makes a 45 degree?? (typically better for performance worse for comfort) perhaps a short stroked sportster engine w/ ducati heads should be the focus of the ducati and a ducati bottom end w/ TC88 heads should be the focus of harley? i really think your on to something here..

  61. No bueno on the exposed camshaft belts.

    I’d like to see something all-new and innovative from H-D. I hope they are learning from GM. They can only milk an image for so long before people get wise. A liquid cooled V-4 that makes 200 HP stock would be nice, something I can actually be proud of innovation wise as an American, not something half American and half Italian. Wake up H-D.