Harley Davidson 4 Valve Big Twin Sportbike
April 7th, 2008 by Paul Crowe - "The Kneeslider"
Digging around in some old images I came across this bike and I have zero information about it but as you can see, there’s something very interesting here. Housed in a custom sportbike frame is a Harley Davidson big twin, with 4 valve heads no less! There is some type of induction system with velocity stacks sticking up through the tank and beyond that, you know as much as I do, … or do you?
How about some help from the most knowledgeable group of motorcycle enthusiasts anywhere, … that would be you, … and let’s see if we can identify who built this, when, where and any other information you can find. (Updated: mystery solved - see below) For all I know, this is some famous custom I just never saw before or maybe it’s a one off that never got much attention.
I enlarged the engine area to give you a better look but that’s about as good as it gets.
Since we’ve talked about big twin sportbikes on a number of occasions and Curt Winter has been building his Big Twin Racers, this seems to fit right in.
OK guys, dig in your archives and let’s get some answers.
UPDATE: Wow! That didn’t take long. First comment from VMX1000 has the link. Here’s all the info on this really sweet build.
1232cc, short stroke, 4-valve, (was an Evo Big Twin), Fueling heads, Cosworth 90mm Formula One pistons, 2 x Weber IDF 40mm twin-throat racing carbs and on and on. 310 pounds!! OK, I am truly impressed! My list of all time favorite builds just grew by one.
Posted in Motorcycle Builders, Motorcycle Design
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15 Responses to “Harley Davidson 4 Valve Big Twin Sportbike”
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April 7th, 2008 at 9:24 am
Nasty machine, love it!
http://www.people.ex.ac.uk/pbhook/harley.htm
April 7th, 2008 at 9:34 am
Thanks!!
April 7th, 2008 at 10:33 am
great find, and a great story to go with it!
April 7th, 2008 at 10:43 am
That was in “Hot Bike” in ‘95 I think, under the title “Spirit of Semtex” or some such thing.
Quite the brutal piece of hardware!
April 7th, 2008 at 12:26 pm
Great piece of bike … Interesting individual too.
April 7th, 2008 at 1:15 pm
Yea,Hot Bike Mag July 1995. The owner is Patrick Hook an Englishman. 4valve short stroke Evo motor and the bike only weighs 310 lbs.One of the pictures with the article shows the skinny owner holding the bike both wheels about 4 in. off the ground.Said he had trouble keeping the front wheel down.
April 7th, 2008 at 3:24 pm
Looks like Buell wasn’t the only one aware of the potential.
April 7th, 2008 at 4:09 pm
I am sure I have seen this bike in the british “streetfighters” mag: http://www.streetfightersmag.com/
From what i remember it was used for hillclimb racing. If I could only find the mag!
April 7th, 2008 at 8:37 pm
Finally, a Harley that wasn’t made for couch potatoes! I like it!
April 8th, 2008 at 12:14 am
Holy smokes! Yeah, that’s a Harley I’d ride…
April 8th, 2008 at 3:47 pm
It is now Dr.Hook and a man of letters, a very accommodating, modest, and all around nice person who saved me a lot of hours with his personal trials of R+D. If anyone wants to build something similar to this beast, I will be very happy to help where I can.jurneyman
April 15th, 2008 at 6:10 pm
I’m pretty sure I took a ride with this guy back in 2002 from the Harley Davidson dealer in Farifield, CA, up to Lake Berryessa and ending at the fairgrounds in Napa Valley. The Hell’s Angels and plenty of other bike clubs were represented, but this truly impressive bike really stood apart from anything else there that day.
June 1st, 2008 at 2:24 am
This bike also has a writeup and great pictures in the coffee table book: Extreme Streetfighter Motorcycles >The Ultimate Collection. by Frank Allmann, Simon Everett. ISBN 1-84193-035-0
It shouldn’t be too hard to find….
June 1st, 2008 at 2:57 pm
As mentioned there is a pretty in-depth write-up of this bike in a StreetFighters magazine issue from years back. I still have the mag. Very interesting build. Starting with an Evo motor, primary drive, and transmission vs. an XL motor was really making a challenge of it.
My favorite part of the story is how the other racers initially laughed at him until he was so successful that he was forced into a higher class.
September 3rd, 2008 at 6:49 am
i would love to no or find out the wherabouts of the 4valve heads..i have a harly twin cam trike and id love the oppertunity to be..erm..UNIQUE..!!,oh and while im on i have a supercharger for a harly twin cam for sale if anyone is interested ok my e/mail is carl.leese@sky.com