1981 Basket Case Missing Some Parts...

Still picking away at it. Going to be able to get back in the machine shop soon (everything was shut down for Covid). Hopefully I will be able to take some time in between prepping next semester's classes to make some "demonstration pieces" for the students. :devil:

Got the exhaust on, rear turn signals installed on the bottom of the seat, headlight fitted, tail light housing has been coped to fit the rear fender, and after much travail I managed to find a tank that fit.

Seems when the PO raked the neck he used the ol' take-an-inch-out-of-the-spine-and-notch-the-downtubes technique; which in turn left a lot less room for the gas tank than I would have preferred. I tried a tank off of a honda rebel, and that was too large (last picture). I was really hoping for something that could carry at least 3 gallons, but but it looks like I'm going to have to go with the wassel due to size constraints.

I love the way it looks, but I'm not took keen on the travel range. A bottle of reserve fuel mounted to the seat tube may be in order.:rolleyes:

I'm not diggin' the drag bars at this point... may be time to explore alternatives. However, I think my next step is to build the faux oil tank to keep all the electronics in. I'm thinking of a horseshoe design with some internal framework to also connect the rear fender to the frame.

Until next time...
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Drag bars are great but yours look too wide. Maybe a little shorter set with more of a back sweep? Can you cut those down?
 
It would be pretty easy to cut the drag bars down, that may be an option... I think it's partially the long risers that I don't like as well... we'll see, plenty of time to sort it out later.

The rockers are a work in progress, hence the plywood. :D The ones pictured are actually Rev. B, and Rev. C is in the works. Even the next set will be pretty long compared to most standard rockers. I have read that sugar bear used to have almost zero trail in his designs, but his designs are supposed to be incredibly stable because of the amount of drop from the axle to the stiff leg of the springer.

The trail right now with these rockers is damn near zero once the bike is off the cribbing. If I go out to the shop and grab that front wheel and lift, I can lift it over two inches. There's a lot of math, geometry, and science behind springer geometry that I'm still learning: fortunately there's a lot of good resources out there.

Here's a really good read on springer design: http://www.choppercompendium.com/ccforum/viewtopic.php?f=34&t=494&start=15
 
Got a little time to work on the rear fender this week. The tail light is something I picked up at a swap meet: the vendor claimed it came off of a hearse of unknown make and model. I pretty much figured that his claim was intended to move merchandise, I'm sure all of his parts "came off of a hearse" and I'm pretty sure that he knew most of his customers were in on the joke.

I wish I had taken a "before" shot of the light, it was all covered in paint and bondo, some of which was splattered on the ring and glass. It took a lot of polishing to get it nice and shiny. Since the body was solid aluminum, I was able to easily cope the profile with a file to fit the radius of the rear fender.

Now all I have to do is fit a light for the license plate. I've found a good housing, but am going to have to design an insert for the LED bulb. (The halogen bulb sticks out too far in the wheel well: more on that next time.)


Heres a few in process shots:
I epoxied an LED module into the tail light. This module plugs into a standard 3-wire socked and will flash 3 times before going constant when activated.
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Here is the housing all cleaned up and bolted into place.
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Trimmed the gasket and installed the beehive glass.
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Made up a mount for the license plate frame. Just have to mount the light to illuminate it.
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Not the best picture, but there's not a lot of light in the back of the shop. Gives the general idea.
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Quick update: been putting in a lot of hours at the school getting ready for the upcoming semester. Due to Covid, I need to develop a lot of online material, and it's a lot easier to do it now rather than during the school year.

But while I've been there, I've asked the other guy who works in the building to orient me on the 3D printer, and I was able to "print" a solution for my license plate illumination. The housing holds one of these: https://www.oznium.com/home-led/home-led-floodlight and will sit flush to the fender. A little bit of filler and some spray paint and away we go!
 

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Well, I finally got a rolling chassis for the first time since I took off the mag wheels... at least I had a rolling chassis until I put the bike back up on the stand to get to work on the rear wheel. :rolleyes:
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I was able to mill out a couple of rocker from some 1018 CRS that we had lying around. This is rev C on the rocker design. It's pretty close, I may have to fine-tune it some more however. One of the reasons that I have to keep updating the design, is that it's hard to tell where the fork geometry will end up once I put weight on the rockers. I never wanted to put full weight on the plywood mock-ups, but I was able to refine the design a little and get closer to where I want to be... at least close enough to take the time to program the mill and cut actual metal.:cheers: Now that I can rest full weight on the front fork, I can get an accurate measurement of the rake angle and trail. If you look at the rockers in the two pictures below, you can see the difference in geometry once I take the bike off the stand and plop myself down on the seat.

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As you can see, there is still about .250 of negative trail when weight is on the forks, I'm not sure if I'm going to adjust the rocker design again or start fiddling with the springs to make the next adjustment. It's also possible that I will need to cut an inch off the forks and re-drill the holes for the shoulder bolts. While installing the rockers, I noticed that a one of the holes in the legs is a bit warbled out. I'm going to have to check them all to make sure they are sized correctly. If they are not, I could over-drill the current holes and turn some bushings on the stiff legs, but there's not enough material to do that on the spring legs. :cussing: If I have to shorten the forks, that'll affect the geometry as well... :umm: It never ends... for now I'm going to put the front forks on the back burner. Next up is the rear wheel.
 
Well, I finally got a rolling chassis for the first time since I took off the mag wheels... at least I had a rolling chassis until I put the bike back up on the stand to get to work on the rear wheel. :rolleyes:
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I was able to mill out a couple of rocker from some 1018 CRS that we had lying around. This is rev C on the rocker design. It's pretty close, I may have to fine-tune it some more however. One of the reasons that I have to keep updating the design, is that it's hard to tell where the fork geometry will end up once I put weight on the rockers. I never wanted to put full weight on the plywood mock-ups, but I was able to refine the design a little and get closer to where I want to be... at least close enough to take the time to program the mill and cut actual metal.:cheers: Now that I can rest full weight on the front fork, I can get an accurate measurement of the rake angle and trail. If you look at the rockers in the two pictures below, you can see the difference in geometry once I take the bike off the stand and plop myself down on the seat.
View attachment 177460View attachment 177461View attachment 177462View attachment 177463
As you can see, there is still about .250 of negative trail when weight is on the forks, I'm not sure if I'm going to adjust the rocker design again or start fiddling with the springs to make the next adjustment. It's also possible that I will need to cut an inch off the forks and re-drill the holes for the shoulder bolts. While installing the rockers, I noticed that a one of the holes in the legs is a bit warbled out. I'm going to have to check them all to make sure they are sized correctlIf they are not, I could over-drill the current holes and turn some bushings on the stiff legs, but there's not enough material to do that on the spring legs. :cussing: If I have to shorten the forks, that'll affect the geometry as well... :umm: It never ends... for now I'm going to put the front forks on the back burner. Next up is the rear wheel.

Hi Irish,
the red lines on the front wheel close-up photo show a small amount of lead.
That'll try to flip the front end around backwards as you ride.
Suggest you drill a series of holes in the bottom link plates to move the axle backwards to find the amount of trail that'll let you ride OK.
 
Yes, that was what I meant with my comment about .250 of negative trail. I could drill some holes to play around with the geometry, but I'm hesitant to move the axle much farther down the rocker. Doing so will raise the forks and thereby increase my rake angle and raise the front of the frame higher up off the ground (I really like the current stance of the frame. I also have some repo harley springs that look lighter than the square stock springs currently installed. I'm thinking that installing the lighter weight springs will give me more action on the suspension and at the same time bring the axle back towards the bike slightly.

I'm really aiming for very little trail... like only 1/8" or so. But I agree that the current geometry is not agreeable. Here's how I draw the rockers up in Solidworks:
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The critical features are the holes, once I have them where I want them; I just sketch a pattern I like around them. One thing I forgot to check on the bike as it sits, is whether or not the line between the axle and the stiff-leg pivot point is holding perpendicular... hmm...
 
... whether or not the line between the axle and the stiff-leg pivot point is holding perpendicular... hmm...

One thing to consider is the spring compression.
Starting at 90°, the upward rotation of the rockers will enter an increasing leverage ratio, diminishing and/or softening the front suspension...
 
Well, kinda.
It's a somewhat complicated study in geometry and "force vector physics".
Unless the springs are progressive wound, they'll have a linear compression force rate.
Then, you have the varying sinusoidal leverages of the rockers, based on the locations of the 3 holes. Followed by the vertical force vectors of the axle and back legs.
Combine all that to get the suspension rate curve, tailored to suit.

Myself, I find compound lever mechanisms fascinating...

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Love it! That pogo seat is rad, nice work. What kind of springer is that? Looks like an old Denver's maybe.
 
Well, kinda.
It's a somewhat complicated study in geometry and "force vector physics".
Unless the springs are progressive wound, they'll have a linear compression force rate.
Then, you have the varying sinusoidal leverages of the rockers, based on the locations of the 3 holes. Followed by the vertical force vectors of the axle and back legs.
Combine all that to get the suspension rate curve, tailored to suit.

Myself, I find compound lever mechanisms fascinating...

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I don't think I'm a good enough engineer to take that explanation and come up with a practical application to my current situation... you're obviously far more advanced in your understanding of such things than I am. If you could dumb it down for a simple guy like me.. o_O Is there a mathematical formula for this application?

Love it! That pogo seat is rad, nice work. What kind of springer is that? Looks like an old Denver's maybe.

I believe it to be an AEE Springer. It's all square stock, and the old rockers were similar to what you see on some old AEE models.
 
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