DesmoHarley - Italian American V-Twin Completed
July 12th, 2007 by Paul Crowe - "The Kneeslider"
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:
Posted in Engines, Motorcycle Builders, Workshop & Tools
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47 Responses to “DesmoHarley - Italian American V-Twin Completed”
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July 12th, 2007 at 8:37 am
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.
July 12th, 2007 at 9:11 am
Chris,
Awsome !
July 12th, 2007 at 10:05 am
Thats #@*&%$! amazing.
July 12th, 2007 at 10:59 am
WOW !!!!!!!!!!!!!!!!!!!
I mean really WOW !!!!!!!!!!!!!!!!!!!!!!
You just blew my mind.
July 12th, 2007 at 12:12 pm
That’s farking awesome. *thumbsup*
This duc-riding rocket scientist is drooling. Engines are neat!
July 12th, 2007 at 1:00 pm
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???
July 12th, 2007 at 1:01 pm
Chris… got another project for you… Design a new case for your HD/Duc engine that uses a cartridge style transmission!
July 12th, 2007 at 2:30 pm
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!
July 12th, 2007 at 2:41 pm
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
July 12th, 2007 at 3:30 pm
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!
July 12th, 2007 at 5:16 pm
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?
July 12th, 2007 at 9:33 pm
” 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.
July 12th, 2007 at 10:40 pm
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.
July 13th, 2007 at 3:37 am
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!
July 13th, 2007 at 12:21 pm
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.
July 13th, 2007 at 1:16 pm
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)
July 13th, 2007 at 2:00 pm
So it was true about the Ducati/Harley merger
That’s a really neat motor .
July 13th, 2007 at 8:17 pm
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
July 14th, 2007 at 3:32 am
Just wait till you guys see my pushrod GSXR…
July 14th, 2007 at 3:49 pm
dodgy- does it have atmospheric intake valves?
July 15th, 2007 at 9:02 am
After installation in some good platform I sure would love to hear and see the end product! Give us another chance!
Reg Lawson
reglawson@gmail.com
July 17th, 2007 at 10:33 pm
H.P. specs. now , im in suspense .
July 30th, 2007 at 11:51 pm
Ahhh, freedom from the pushrod!
August 5th, 2007 at 4:03 am
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.
August 9th, 2007 at 2:06 pm
Add a double mag setup and you should be ready for the men in white…
August 22nd, 2007 at 11:36 am
This would be absolutely outstanding in one of the Liberty CycloCars that the
Kneeslider profiled some time back!
September 1st, 2007 at 1:52 pm
That is such a beautiful piece of engineering…
September 7th, 2007 at 11:06 pm
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.
September 11th, 2007 at 11:33 am
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!
September 12th, 2007 at 4:21 pm
Wow. A Harley Desmoson. i really need to see where this motor is going to live.
September 23rd, 2007 at 7:06 pm
FRIST vearyyyyyyyy cool. what wood it cost .andcan you go bigger in the cubic inches.
September 25th, 2007 at 8:06 pm
Absolutely stunning! Great job!
October 21st, 2007 at 1:12 pm
Leave it to a guy like Rick A to get all Spock- like on the cool Duc-Davidson .Why do it? Because he can !
October 23rd, 2007 at 6:59 am
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.
November 5th, 2007 at 8:27 pm
never let them say it couldn’t be done,good form old chap,you’ve out done your self!
December 4th, 2007 at 7:57 am
looks like a good motor for the bonneville salt flats
December 17th, 2007 at 2:21 pm
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.
January 3rd, 2008 at 1:40 am
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.
January 9th, 2008 at 11:21 am
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.
January 9th, 2008 at 11:35 am
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.
January 15th, 2008 at 6:13 am
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?
January 17th, 2008 at 11:08 pm
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.
January 21st, 2008 at 6:42 pm
Absolutely, Joe Barker.
And well done Dancing Bear for setting the Desmo straight!
March 31st, 2008 at 3:11 pm
Double D
Ducati-Davidson,
Very cool, just because you can & did, put it in a feather bed frame…….
April 8th, 2008 at 4:20 pm
Now lets see a pushrod ducati monster….!
May 7th, 2008 at 9:51 am
Does anyone know if Chris has a website?
May 7th, 2008 at 10:36 am
Chris has moved back to the U.K. His new website is Desmohog