The Hodaka Club Forum

Whoa! Good illustration Ed! Yes, I considered welding on a tab for third bolt but this thing is rock solid. With the stiffness of the plate and the circular contact with the boss this thing feels like part of the frame. The washers you mentioned will help even more. These are not even stand-on pegs due to the seating position. Meanwhile I've built a less fat prototype plate and put a bit more drop on the peg. Hey, this is fun stuff!

Maxie

Hmm, It just occurred to me that the final plate will be flush with the swing arm boss and a washer could be put both ends of the swing arm bolt insuring flat contact with the frame via the spacer. More to come as I try this.

Maxie! That's a slick idea for positively clamping down the front of the peg plate!
Ed

Max,

First of all, you are doing prototype experiments here, so try whatever comes to mind. Why not.

But..... don't do the two or three hole design on the legs. All this does is make weak points where the arm will bend. Quarter inch aluminum isn't structurally sound material to begin with. Creating flex points will just make it easier to bend. I can bend quarter inch aluminum by hand if one end is clamped down, as your extensions will be.

The other bend point will be at the down tube because this will be the fulcrum under the lever that is the extension arm.

No, you won't be standing on them. I got that. But you will be bracing yourself against them, and on a motorcycle you can't always be gentle on the foot pegs.

Bolt one up, sit down, push back with a foot and watch the extension arm. If it flexs enough for you to see it flex, it will eventually fail. That would be ugly at 100mph. I think you will eventually need some sort of three dimensional backbone on the extension arm to resist flexure, and the backbone will either need to be attached to the downtube, or pushing against it firmly so that tendency to bend is transmitted into the downtube at a right angle. I would draw a picture, but don't have the photoshop tools Ed has.

Wear pointed toed shoes, as to theory you will go faster. Use two stirups from a small saddle, thrown over the fender as they adjust and are made for a little flex Did you get the Van Tech?-----Clarence

taber hodaka wrote:Wear pointed toed shoes, as to theory you will go faster. Use two stirups from a small saddle, thrown over the fender as they adjust and are made for a little flex Did you get the Van Tech?-----Clarence

Whoa! The Van Tech thing got out of control! I was out early after testing the waters. I was going to go a couple of hundred but that didn't last long. They would have been cute on the Day One Project. Somehow I've already got too many projects started at once.

Max

A couple of items of note. I don't know the grade of this aluminum plate but It seems to be exceptionally stiff and tempered. Hole drilling lightens and exhibits design but can weaken parts. All holes in the two prototype pieces have at least 5/8" of material surrounding them. Of course the final test will be to build a final and see if I can make it fail. All part of the process. Advice helps, I'm not a certified engineer, but I do study something in depth before risking life and limb on it. Projects like this certainly are educational (and fun), again all part of the process. Thanks for everyone's interest!

Maxie

Max, google "rear sets rearsets" and review what others have done. And even at add-on passenger pegs. This will at least give you an idea of what worked before.

The Van Tech caper on eBay went bonkers!! This was my first serious auction and I pursued it strongly. I'm convinced that one other bidder used an auto-bidding program. He responded too-instantaneously with counter-offers.

I'm still looking for a set of Van Techs. Holler at me, Clarence.

E bay bidding is auto, if the other bidder bids less than you, you win for the $$ of his last bid plus the increment. Trying to raise the bid in the last second does not work. Bid the amount you would be willing to pay. -----------Clarence

[quote="Bill2001"]Max, google "rear sets rearsets" and review what others have done. And even at add-on passenger pegs. This will at least give you an idea of what worked before.

Hey Bill, Yes, I've Googled, E-bayed and Amazoned this subject to the max so to speak. Hours probably. By using this plate, I'd like to have the control shift and/or brake shaft go through the plate in a mounted bearing with the crank on the inside of the plate. Most of the ones I see have a bolt on footpeg with the lever and pivot arm on the outside. The good and expensive ones have the arm angle adjustable to any degree. Just studying the situation. Once I get the plates in position I can get a bit more serious on the mechanisms. Here's one in the cart that looks to be a possibility. $80, USA, adjustable pivot arms. Check it out.

Max

hodakamax wrote:I don't know the grade of this aluminum plate.........All holes in the two prototype pieces have at least 5/8" of material surrounding them.

Maxie

Max,

There is a formula for determining the amount of force needed to bend aluminum stock. Two of the variables in that formula are the tensile strength of the stock and the width of the material to be bent, multiplied together. Since we don't know the tensile strength of your aluminum stock, we can only demonstrate the relationship between full flat stock versus stock with holes drilled for lightness, rather than actually computing the true result, but really, the only question raised here is just how much drilling reduces strength, all other things being equal. So, all you need to do is measure the width of the stock as drilled versus what the full width is at the point it is drilled, and create a ratio.

For example, let's say that at the point your stock is drilled, it is three inches wide, and after drilling the hole, the total width of remaining stock is 1.125" (5/8" times two). The relative difference in strength regardless of the alloy or temper is the same: 1.125" / 3.0" = 0.375. With these dimensions, the resistance to bending after drilling the hole is roughly one third (0.375) as strong as it was before drilling. No matter how stiff the stock may seem, drilling lightening holes greatly reduces its native strength, while at the same time reducing weight by only a negligible amount. I would not give away two thirds of the strength of the stock just to save a quarter ounce of weight, or to make the part look artistic.

You have certainly read up and researched the subject adequately. Give it your best shot and if it breaks, improve it. All these niggling details can drive one nutso, but it is so nice to look at the product years later.

Thanks Jack. I think we all agree that holes weaken parts. I admit that if I want to reduce weight, the quickest way is to put the rider on a diet. I could easily give up five pounds rather than weakening parts grams at a time. Art is part of this project so I'll have to design the part to meet requirements rather than to be as strong as possible as in overkill. A fine line sometimes. I find aircraft an interesting design and challenge for the designer. It must be strong, light and aerodynamic. Lotsa holes are drilled to meet the weight requirement. It all adds up. Or a spacecraft where grams are big money in launch costs and/or payload limits. I guess what I'm saying is that I have the problem, I'm trying to build this project with some parameters. In this case it is like an aircraft. Requirements are similar, light, aerodynamic, strong, fast, hopefully safe and should look good with innovations. I don't know if I can meet all these requirements. Projects like this are a challenge, a game to me, a giant model or piece of art. All quite entertaining I might add!

Just rambling and being philosophic this rainy day. I always appreciate your and others advice. Part of the game is to please the Gang!

Max

I've always liked the design aspects of your drilling and lightweight creating effects, Max. You did a similar design & function with the previous chain guard on the last project. It was fun to watch! Again with this piece, it DOES have a rather aerodynamic aircrafty (pun intended) look to it. And I'm assuming you'll use the same design but reversed for the other side? And then there will be the relocation of the brake pedal as well! Good luck & I can't wait to see the final results for both sides! ,Victor

Art is part of any project. Verily so.

One rule of thumb on RC aircraft built for competition, which have to be light and strong: make the part lighter and lighter til it breaks, then strengthen it so it doesn't break.

Hmm, I haven't had to construct a cone for several decades but I took on the challenge. This project is supposed to be educational. Home-made does't mean hiring it out. After I got the mounting bracket cut off, I did remember that a cone is part of a circle. Two rulers determined the angle and radius and my stick compass marked the circles. Now the fab guy can play with the cut-outs before cutting the piece out of metal. Fun.

Maxie

Actually, the math is fairly simple. If you have the diameter at both ends and the distance between the two circles, the angle becomes automatic! Victor

Hmm, more than one way to skin a cat. I had to start somewhere!

Max

True! And is there anything inside that cone or is it just an open expansion chamber? ; D Victor

Here is an easy way to design the cones. It is a cone calculator. Go to this website:

http://www.cmrp.com/cone-calculator

Just input the numbers you have and it will do all the work.

Thx.

I've been worrying how are we going to keep everything in position when the cone is replaced. I built this quick jig that should make fitting and alignment easier. The cone to be replaced is in contact with the base board and everything else is shimmed to fit. Should work. Only two screws for transport and the pipe snaps in nicely.

Max

And thanks DR, I did play with the calculator but I had to draw it anyway for the pattern.

And Victor, the only thing in the pipe is a slip-in silencer that goes in the stinger.

Well, I kinda figured with this kind of pipe. Hoping the metal shaping goes as well for you Max! Victor

It's been decades since I built an all out Hodaka engine. All speculation and questions at this point but I have began to shop for or at least discuss a carb for this project. Road racing and top speed are top considerations but performance street is not out of the question. All our race engines of the past used 32mm Amal concentrics but that was a long time ago. What's the modern consensus on brand and mm. 34mm too big? Amal/Mikuni? Opinions? Displacement will be 100cc. Personally and historically I'd like to stick with the proven Amal, but Mikunis are half the price new and Mikunis are certainly proven equipment.

Max

It depends on what the bike is going to be. Will it be a concours, parts-correct bike of the type of that era? Or will it be your interpretation of a bike of this type using current parts and technology. Your "daily rider", so to speak. The Amal is a fine carb but is it necessary to complete the vision if this bike? The Mikuni is a good carb and it's practical.

But Jack on a hot day it looks cool. Maxie uses the cosmic look. If it doesn't function he will reinforce it or put it in the recycle box----- Clarence