1914 Harley Davidson Similaria

The engine choice was almost a “no brainer”.  I wanted a 45 degree V twin and I did not need or want a big twin so the Sportster engine emerged as the answer.  I have owned a 2003 883cc Sportster and I have also ridden the 1200cc version and I preferred the 883 due to my perception that it transfers less vibration to the rider.  I wanted a 2003 or before because the rubber mounted feature of 2004 and later models, while more comfortable, became more complicated to construct with the rubber mounting of the engine with the attached exhaust pipes.  On this rubber mounted engine the exhaust system is connected to the engine in its isolated vibratory envelope and not rigidly tied to the frame directly and I did not want to figure how I would mount that system with the Arlen Ness frame that was not designed for it.

The Arlen Ness frame was also the obvious choice for the frame.  This was great news, not only because of my desire to use the Sportster engine, but also good news because that frame would make provision for the unique way in which the Sportster engine mounts to a frame. The rear of the engine attaches with 4 bolts to a relatively vertical plate on the frame which faces forward. To add to the good news, this frame was designed to give the correct alignment of the transmission’s drive pulley to the rear wheel’s driven pulley.  The frosting on the cake was that the Arlen Ness catalogue also showed that they made the two mirror image flat sided style gas tanks that attached to each side to the upper frame tubes.  They also made the oil tank.  

Next step was to order the frame and get some confirmation on its suitability for my vision.Now I that I had the frame I gave the Arlen Ness folks a call to get the gas tanks and oil tank.  That call revealed they no longer made any of the tanks! Oh boy!  Was I up to the challenge of making them?  I had not done that before.  With further thought I realized these tanks had mostly flat surfaces and I did not have to learn the fine art of using an English wheel and a panishing hammer to form them.  However I also realized that for the gas tanks, I needed to not only make two gas tanks, but had to make two exact mirror images that mated with each other where they connected to the frame.  The oil tank would be a more straight forward fabrication being a basic rectangle.  

I decided I was up for the challenge to fabricate these.

Oh I almost forgot, it was then time to get the engine. 

SIDE BAR: My preference for all my builds is to get a complete running donor motorcycle and ride it for at least 500 miles before starting the project.  This does three things.  First, it gives me the assurance that the entire operating system is working properly or it allows me, if necessary, to make any needed changes or repairs BEFORE the build is started which saves me from making repairs around the newly painted/plated surroundings.  Secondly, if I go to startup and ride the new creation and something does not work, I have some level of assurance that the parts I am reusing DID work when I put the 500 miles on the donor which limits the trouble shooting process to the changes and additions I have made.  Thirdly, I save time by not having to keep picking away at swap meet after swap meet or on eBay looking for parts and hoping they function properly.  The running motorcycle has all the parts needed to run.  This approach has served me well but yes, there is certainly a price to be paid in dollars for this approach because buying a complete running motorcycle is definitely more costly than buying all the needed bits.

So I bought a donor motorcycle with only 4,065 miles on it.

I did ride it 500 miles and discovered the valve guide seals were shot which was subsequently easily repaired on this stock bike.  

Work then began by removing the engine from the stock bike. All electrical attachments were disconnected along with the gas line, mechanical connections like the throttle and choke cables.  Carburetor and exhaust were removed.  The object was to get all things removed so that the bike can be rolled over on its side with only the engine bolts holding the engine in place.  Then a bunch of wood blocks were cut up to support the engine such that it would remain in place on its side when the engine bolts were removed.  Then those bolts were removed and the frame was lifted up off the engine.  Then the new frame was lowered over the engine and bolts secured it in the new frame.

Next priority was to get this assembly supported by its wheels.  The rear wheel was needed to be mounted with the drive line figured out.  If a chain was to be used the alignment of the engine and the wheel sprockets needed to be figured out.  The distance between these two sprockets is not so critical because chains are available in any length.  However, as I had mentioned, my plan was to use a belt drive but these seemed to be available in a limited number of lengths.  Fortunately Arlen Ness had this figured out with the position of the engine and the slots for the rear axle.  I did make up some custom axle spacers to get the rear wheel and its belt pulley aligned with the engine’s pulley which put the wheel centered in the frame.  

Next step was to get the front of the motorcycle supported with a wheel.  Getting this figured out with the front end was a bit tricky.  When I envisioned the style of gas tank I was going to make, I wanted its top flat surface to sit level when I got on the bike.  If it sloped up a bit toward the front of the bike when parked that would be OK.  What I did NOT want was to have it sloped down at the front in either one of those scenarios.  With the more usual rounded gas tank tops found on most motorcycles this is not as critical because this angle is less apparent to the eye.

Also, to get this orientation one could usually tinker with the front forks as well as the rear shock.  But here, being a hard tail, the rear frame height was established so I needed get the front end’s dimensions right.  I wanted to use the springer style forks and Paughco made the style I was looking for in various lengths and they had the ability to custom make them to the length I wanted.

But what length did I need?  Where is the length measured?  That might seem simple but there were numerous variables.  The fork sat at an angle.  The axle sat at the front of a leading link.  If the length measurement started at the top of the lower triple tree, how far will this surface sit below the bottom of the steering head?  If the lower end of this dimension is the center line of the pivot where the leading link attaches, then how far up did the springs allow the axle to move when the frame is weighted down when I’m sitting on the bike?  I made a full size drawing to help solve this.  

Paughco was as helpful as they could be in answering these questions but I was getting the feeling that the only way to proceed was to buy the closest fit on their stock length options and go from there. Which I did.  2 inches over.

I fitted it up when delivered with the front wheel and tire and determined that I did need a custom length at 1 inch over. 

We now had a rolling chassis.

Step one was to make mock-up versions of the tanks.  These were made out of FloraCraft rigid foam that I bought from Michaels and they were repeatedly cut and trimmed until they had the shape and volume I was looking for.

The top outside edges would have a “soft” looking ½ in. radius corner.  So I went to a local fabricator who made four 30” long 90 degree angles with a 4”’ side and a 6” side out of 19 ga. steel that was .059” thick.  They made the 90 degree bends with a ½ in. radius.  The 4” surface would be the tops and bottoms and the 6” surface would be the sides.  One of the real time consumers was performing the fitting work for making the sloped rear sections of the top and outside side that were angled “down” and “in” as it approached the seat area.  Did I mention having to make TWO exact mirror image tanks?  The rear end faces were flat plates but the front end pieces were hand formed at a 6“ radius to conform to the identically hand cut radiuses on the front of each tank. 

Then there was the design and fabrication of a mounting system.  

 Referring to the sketch above, the system I came up with was to fabricate a top hat looking piece with a hole drilled into (but not through) the rim end of the top hat and tap it for a ¼-20 bolt.  A hole was drilled into the tank and the piece was fit into the hole and the rim would rest against the tank’s surface and it would then be welded to the tank around the rim. What this did was to create a mechanical connection with the rim against the tank and the weld would seal the connection.  Eight of these pieces were made, placing two on the top and bottom of each tank.  The two tanks would be attached to the frame with four 1 ¼” x 6 ¼” x 3/16” steel bars that were made with holes at each end.  I did not like the look of just straight bars so I set them up on the mill with a radius cutter and gave them a “waist” look.

Two of the bars were welded to the bottom of the lower top frame tube which would support the bottom of the tanks.  The other two bars straddled the top of the upper top frame tubes and were welded in place holding the tops of the tanks in position.  Large rubber grommets were put in the holes at the end of these bars.  ¼-20 bolts were put through the grommets into the top hats in the tanks.  The rubber grommets served to be a cushion for the tanks to sit on as well as helping to somewhat isolate the tanks from the engine’s vibration.      

Holes for the filler caps and fuel taps were drilled in the tanks to accommodate the bungs for filler caps on the tops and fuel taps on the bottoms.  

All the pieces were tack welded together. Was I going to do the finish welding on this?  5 gallons of gasoline resting between my legs going 70 MPH down the road.  I don’t think that is a good idea so off the assemblies went to my friend and superior welder Lyle, for finish welding.

These tanks were mounted with brass bolts and washers. 

Like the gas tank, a Styrofoam oil tank was first made and put it in position which gave me some level of confidence in the size, shape, and location of the tank that I was planning to make.  My design called for two main U shaped sheet metal pieces to make up the oil tank (see below) and they were also bent up with ½” radius corners by the same local fabricator that bent the gas tank angles.  I drilled holes for the four mounting bungs (same as the gas tanks), the filler cap bung, the oil supply fitting and the oil return fitting and then tack welded these 7 pieces in position with the two main tank pieces.  Then off they welt to Lyle for finish welding.