Heads stay same position. Crank cheeks are shaved, a new pin is made, stock rods are shaved on lower end, and a second sproket is used for the cam chain. Stock cams are used and a second set of points are added to the points plate. Also internal oil passages are lost so external lines have to be used. The problem with this configuration is the placement of the intake/exhaust. Its been done before but would not look good on this bike.
About 15 years ago I built this same engine with a fake rear cylinder. That allows for opposed intakes, more like a Harley instead of both intakes being on the rear. I am working on a new cam and rocker box for the rear to allow the intakes to face each other.  

Hi James.
My 1965 Senior Sportsman was an eBay special. I think I paid a record price for one of these ( $800.00 ) but it was close enough to go pick up. It had been sitting in a barn in Yucaipa for the last 40 years. It came as a roller which is nice and straight. I paid what I did for it as these are pretty rare only being made for three years ('63-'65) and the unmolested condition. Plus '65 was the year Simplex went out of business, so that model year had very few built. I was going to use a Honda OHV 8hp with a TAV torque converter but that combo is just too wide. These senior sportsman`s are very narrow. My new XL V-Twin only sticks out beyond the frame about a 1/2'' so it fits perfect.  

illMATTic:
To build a V-Twin is a lot of work. Engineering, Machining, Welding, and a ton of hours. A V-Twin is nothing though compair to turning a straight 6 into a V-12 !
Take a look at this build:   http://thekneeslider.com/honda-cbx-v12-by-andreas-georgeades/

After considering how difficult it would be to find a Continental red seal engine, I scraped that idea and focused on the “cool” factor.... Wouldn’t  it be cool to have a ½ scale Harley or Indian looking bike ? So I bought 2 Honda XL75 engines for parts to build a V-Twin. The XR75 is perhaps a better engine with a 5 speed transmission, but it would never pass the Dept. of Motor Vehicles as the XR was an off road only model so I went with the 4 speed XL model which will pass inspection without any issues as it was a street bike from the factory.
I have already bought about 90% of the parts I need for this build, and will be using N.O.S. Honda controls, levers, throttle, and wiring harness to keep things simple and sanitary looking. The engine cases will get welded over where it says “Honda” and the Simplex logo will be engraved with a CNC mill.

At this stage the engine is just sitting loose in the cradle of the frame. Next step is to build a frame jig which I have already started, so everything will line up correctly. Once its mechanically built and all the bugs worked out I`ll break it down and do a full restore. I will post more photos in the future as this project progresses.

WATER SLIDE DECALS
These are just like the old decals we used in the 40`s through the 70`s before everything changed to vinyl stickers. Soak in water for a few minutes and slide on to your tank. Then top coat the whole tank with clear urethane. These are about .004 inch thick so they look like they are painted on after the clear coat is done. These were just made a few weeks ago so they are fresh with no issues. Old stock decals are usually hit & miss if they will work or not as they can get brittle after 40+ years.
All I have is what you see... Made for the Senior Sportsman. The strips where it says "Simplex" and where it says "Sportsman" are clear material, so whatever color your tank is, the strips will also be that color. Same applys to the pin stripe around the "V" it will show the tank color. The gold color is a fine metallic, close to the original decal and made the exact size. The sample photo you see is a quick rattle can paint job on one side only just for display with 1 clear coat after applying the decal to show how the color comes through the background.

I have 40 sets available at a cost of $30.00 per set including postage to the USA
International sales are $25.00 per set PLUS the exact postage to your location
If interested please send me a message through this site and I`ll give you payment information.

Any rare bike is only worth what someone is willing to pay for it.

For What ever its worth... That bike is a late 1964 model. The Senior Sportsman was only made 1963 to '65. Some where produced in 1966 but they were badged as a Valient. 1963 had a long plate on the steering stem, and a narrow flat plate on the top of the tripple tree. Early '64 was exactly the same, however... Late 1964 had the same long plate steering stem, but used a wider top plate on the tripple tree that had a dip in the center that looked like a "V".  The 1965 model used the "new" tripple tree plate, but they shortened the length of the plate between the frame tubes and the steering stem. The '66 model had the same gas tank graphics but the name Simplex was removed in front of the "V". Also... '65 had a rear grab handle as part of the frame that year and a down tube was also removed in the rear of the cradle.

ENGINES:
Two continental engines were used on these bikes. The AU10 Red Seal 175cc (7hp) and the a smaller 4.9hp. Also.. A Tecumseh 3.5 hp was available on request. The Tecumseh used the open cradle frame. All the above used forward foot pegs. There was also a Villiers 200cc 4 speed (11hp) model that had its footpegs directly under the rider instead of the forward position, and had a different shaped rack in the rear. Also... Though not in the catalog a Tecumseh AH-58 2-Stroke could be ordered. This and the Villiers are the rarest to find today.

That bike in the photos seems to have the Red Seal engine in it which are very hard to find today in any condition. The vintage Go-Kart guys use these and are willing to pay for them but if you were able to hook up with some of those guys you maybe able to get that one in order. I would see if the seller has the kick start for it. Not all Sportmans had a kick start as it was an option, but if it did come with one it would be a great bonus. You didnt state the selling price, but I can tell you in So. Cal. that bike in that condition would sell for between $500.00 and $1,000.00  Like I said before... Its worth what someone is willing to pay for it. 

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