Land Speed Racing Mk2

[HondaJohn]

The madness is officially starting again

I've started collecting the major parts for the next land speed racer project. I have no intention of making this one road legal, it will be specifically set up for speed. No front brakes, no lights, nothing that doesn't need to be there. The donor bike is the carcass of a 1979 Harley Davidson Sportster that I picked up on Craigslist. The bike had been stripped for a chopper project, so I picked up the forks, frame, swingarm, and gas tank. I am going with a Harley because of the enormous space for an engine in the frame. It will give me plenty of option for engine, transmission, and turbo/supercharger combinations.

After I brought the bits home, I discovered that a small peanut tank I had purchased years before was a perfect fit. I traded the stock tank back to the previous owner in exchange for the correct rear fender struts.

I also machined some bushings so I could install a pair of shocks that I had laying around. They had come from a different model year and used larger bolts, so I modified them to fit.

Finally, I temporarily installed a spare wheel to make it easier to move around the garage.

[alexanderfoti]

I will be watching closely!

[pietenpol2002]

And the engine/trans combo???????????????????????????

[HondaJohn]

I'm not entirely sure what type of transmission I will use, or whether the bike will be turbo'd or supercharged. I'm pretty sure I'm going to use an air-cooled v-twin as the powerplant, but I haven't purchased one yet. Right now, I'm focusing on building a solid rolling chassis, and will buy the engine parts as I get the money for it.

I picked up a pair of beat-up fenders from Ebay and installed them. Slightly more weight, but in my experience, its a sacrifice you want to make, to keep sand and little rocks from whipping up at you. It will also be necessary should I manage to get to the salt with this one

Today, I picked up a pair of cast aluminum Harley front wheels from Craigslist. They are both 19-inchers, and are extremely low weight compared to "normal" Harley wheels. The pair of them weighs slightly more than the one spoked wheel I temporarily installed in the frame. Hopefully, I can mock the chassis up next week.

[alexanderfoti]

I would be very interested if you god down the supercharger route as thats what I have been interested in doing.

[HondaJohn]

I'm leaning towards using a supercharger, since that was what I used on the first racer, and I've got a bit of experience with them now. Its still too early to know for sure, and I may come across something different between then and now.

I installed the wheels so I could mock up the chassis and start measuring for wheel spacers. The bearings on both are totally shot, so I'll have to budget for new ones. Sometime this week, I'll be getting a replacement kickstand and a set of clip-on handlebars to complete the rough build. After that, lots of machining, adapter fabrication, bodywork, and repair/painting.

[HondaJohn]

I've been busy with race-prepping the chassis, and here are some progress shots of the latest work. I purchased a stock side stand, but it is extremely large and heavy. Additionally, the racetrack requires that the side stand be zip-tied up prior to every run. To save myself some time and weight, I made a quick-release pivot bolt for it. This allows me to quickly remove it before racing.

[HondaJohn]

The supply of air-cooled v-twin engines has completely dried up in America, but I was able to get my hands on a used one two days ago. It will arrive sometime this week, and I'll keep you posted!

[coachgeo]

Glad to hear it. Look forward to your progress using this new motor.

[HondaJohn]

I will post a bit more in depth later, but here are some quick progress pics so far:

[HondaJohn]

I've been at this on and off for too long, and now I've got all the major parts gathered up. Time to kick this build into gear.

The tank was sandblasted, and I then had it powdercoated. This should resist staining from leaking fuel.

I also started adding the engine mounts to the Sportster frame:

[HondaJohn]

Progress pics from fabricating the rear motor mount. First time I've done serious welding in a long while, so it's a bit rough. Gonna have to do a lot of grinding!

[HondaJohn]

[UAofE]

The supply of air-cooled v-twin engines has completely dried up in America

Not any more. There are two new ones for sale in Denver.

[HondaJohn]

[HondaJohn]

During the summer, work has slowly progressed on the second diesel bike. The first major milestone was installing the welded motor mounts on the Sportster frame. I hit a snag when a hidden rotten section blew through, but I was able to clean it up and cover it with a welded patch.

[HondaJohn]

The next step of the project was to fabricate and install the front engine mounting plate. This required a bit of headscratching, because it was necessary to carve a clearance into the engine block, in order to avoid modifying the front frame bend. As a result, the frame had to pass THROUGH the mounting plate.

I accomplished this by machining a pair of slots into the plate that allowed the tubes to pass through. Next, I welded a brace underneath the tubes that joined and strengthened the three edges of the plate.

[HondaJohn]

After the frame was finished, I replaced the wheel bearings with a set of homemade tools. I took the opportunity to upgrade from the old two-piece tapered bearings to single-piece ball bearings.

[HondaJohn]

First Test Start:

https://www.youtube.com/watch?v=w__PuomZQGo

[alexanderfoti]

Sounds excellent! Make sure you check the Injection timing as it sounds a bit off there

[HondaJohn]

The engine in the Diesel Sportster is 3 times larger than the engine in my first bike, so it requires an electric starter and a fuel pump to operate correctly. It also has a heavy-duty solenoid that holds the governor open, and snaps closed to shut the engine down when the kill switch is used. These are all relatively high-amperage systems, so a single fuse and normal switches were not enough to safely control them.

For the electrical system, I used a marine-grade 6-fuse block and a pair of automotive relays. The fuses protect every individual circuit which will simplify troubleshooting, and by using relays I can avoid sending high amps through the relatively fragile handlebar switches. All of the wires are color-coded, with yellow wires for the starter system, white wires for the governor solenoid, red for main power, black for control switch power, and green for ground.

The fuel pump is another marine-grade unit which is rated for most types of fuel, including biodiesel.

Now that starting was done, it was time to focus on stopping. The original Harley calipers suffered an extreme design flaw. The bolts that held them to the swingarm screwed into nuts that were captured in hexagon-shaped holes in the alloy caliper body. Unfortunately, when these need to be removed and rebuilt, the bolts have inevitably seized from rust and the nuts tear open the hexagonal holes, wrecking the casting and making it impossible to tighten the bolts correctly during reassembly.

The caliper I purchased (for cheap) of course had been discarded because of this damage. I drilled out the old shoulder bolts, milled the hexagon holes round, installed steel spacers to keep the new nuts from gouging into the alloy caliper body, and installed modified 7/16 diameter socket-cap bolts and locking nuts.

[HondaJohn]

I am jumping ahead a bit, but here is a quick status picture

[HondaJohn]

Between fabricating major components, I quickly made a simple seat for the Sportster diesel. I used a piece of flat steel plate, cut it out to match the frame rails, bend the end to match the fender, and had it powder-coated flat black. The front has a notch that slots against the original seat bracket, and the back is held in place by a button-head bolt.

[klondikekid]

Nice work, your almost there, I like your anvil/vise never seen one like that before.

[HondaJohn]

The transmission mounting plate is one of the most important pieces of the entire motorcycle, and took 3 weeks of planning to properly fabricate. I do not have access to CNC machinery or a large mill at the moment, so it was necessary to manually carve the plate using a band saw, a drill press, assorted hand files, and a block sander.

The plate must perform several functions. Most importantly, it serves as the mounting surface for one of the countershaft bearings. For the CVT transmission to work correctly, the center-to-center distance of the two shafts must be set to a precise dimension (in this case 9-3/4 inches). Therefore, the placement of the bearing block on the plate, as well as the plate's mounting location on the engine block, are crucial.

Additionally, the plate acts as a major structural component. On one end, it is tightly bolted to the engine block. On the other, it is fastened to a large threaded rod that is mounted in the central frame casting. This is extremely important, because it allows the force from the engine to be transferred through the heavy aluminum plate, rather than through the frame tubes. It also improves the rigidity of the whole chassis.

Step 1 - Layout the overall dimensions on the material.

My "Manual CNC Machine"

Step 2 - Begin carving outer shape, and drill layout holes. Use 1 inch holes for the shafts so that the plate will accurately locate on the crankshaft

Step 3 - Locate the plate on the crankshaft, and determine the position of the hole for the large threaded rod.

Step 4 - Drill hole for threaded rod, and finish carving the rough shape.

[HondaJohn]

Step 5 - Prepare threaded transfer punch.

Step 6 - Install the threaded transfer punch in each engine-block bolt hole to be used, and hit plate with a hammer to punch the locations for the bolt holes to the plate.

Step 7 - Mark out the locations of the mounting holes

Step 8 - Drill and test-fit the mounting holes.

[HondaJohn]

The main drivetrain bearing is mounted to the central frame casting on a pair of machined aluminum blocks. This bearing had to be perfectly aligned to ensure that the secondary shaft was perfectly parallel to the engine's crankshaft. Additionally, the bearing must be strong enough to support the full force of the engine's power while transmitting to the rear wheel.

I made the bearing blocks out of 6061 aircraft aluminum and assembled the parts using automotive suspension-grade flanged bolts and nuts.

[HondaJohn]

Testing the new exhaust system:

https://www.youtube.com/watch?v=2sn164sOMbY

[HondaJohn]

I decided to build a 2-into-1 slash-cut exhaust (which is to say, I had just enough leftovers to make it work, and I'm feeling cheap after shelling out for the CVT transmission).

This is my first attempt at building an entire exhaust system by myself, so the welds are snotty, the whole thing was made from leftover scrap pipe, and ultimately I covered the whole thing in fiberglass heat wrap to hide my shame. Here is the whole process in its gory, splattery detail!

[HondaJohn]