The Hodaka Club Forum

A somewhat basic mock-up here for the cable rear brake. A crank rotating around the center of the foot peg to pull the cable should work.

Max

That rear brake cable is a great idea. The Honda CB160, and others, used a rear brake cable-- it might pay to look at manuals and see how they did the linkage.

I remember that OSHMO has some nice rearsets for BMW airheads that you might get ideas from.
They are at http://www.oshmo.com

Ah, thanks Bill. I see they have the crank incorporated with the lever and/or on the shaft. I can always use ideas!

Max

Looking at what has been done is always good to get fresh ideas or to confirm that your idea is workable.
You might want to google "motorcycle rearsets" for more examples.

Max it is mock up, but you would want the backing plate stay to pull not push??//-------Clarence

Good question Clarence. This is the position I need the brake plate to be. I've already wondered about that but I can't see why it wouldn't work. I would think the link should work under compression as well as pull with adequate strength. Of course the brace would be stronger under pull as the brace could collapse under compression especially if it was long and flexible. Opinions?

Max

I'd put my two cents on a tension link for the brake stay. Make up a custom cable to allow it to work. From what I see, a significantly shorter cable would work with a tension link set-up - and the short cable would be better due to shorter housing and reduced compression of brake cable housing AND a more direct/straighter cable path. OK, four cents (got carried away).
Ed

Thanks Ed, well, that's what prototyping is all about, putting the best design together. I liked the vertical loop of the cable to accommodate the suspension but it all depends on the crank design. Tension is definitely the way to go for good design on the brake plate. At least we're all heading in the same direction! I'll try some options as it goes along.

Maxie

DOH! I did sort of forget about the rear-set position and suspension movement, yup that may dictate a bit of extra cable length.

Like you said, that's what prototyping mock-ups are for.

Ed

And to toss out more choices:

Keep the compression brake stay you have, but add a welded strengthening rod like you did on the brake pedal on an earlier bike. Sure, the stays are usually in tension but these are 4" drums on a 200 pound bike. And it will always be a conversation point at the track. Until you get tired of hearing it.

Rotate the backing plate around to the "stock" position so that the brake stay bar is "properly" in tension. The splined brake cam shaft will be at 10:00 (?) but remember that cam/brake lever can rotate either direction. See if you can find a happy arrangement with the brake lever, the cable and the (repositioned) cable-end bracket. The only constraint is that the angle between the csble and the brake lever should not exceed 90*.

Keep the cable-brake arm arrangement you have now, but weld another brake stay bracket to the lower side of the backing plate around 5:00 to give a nice brake stay in tension.

Pick the best setup.

Hmm. Interesting. As you move the axle back as in chain adjustment the brace to prevent rotation becomes parallel to the swing arm and the angle of the cable also rotates forward. A parallel brace should go into tension as the brake plate starts to rotate. By the way, the brake plate is also clamped tight by the axle to the swing arm or at least should be. I'm starting to think our brace is plenty strong either in compression or tension. The force being applied comes down to tire contact to the road. As Bill said, this is a teeny rear brake to start with. I guess I'm the rider, any flaws in my thinking?

Maxie

I'd steer clear of any brake stay positioning which approaches parallel with the swing arm. That would also "approach" the effect found with a slightly loose brake stay arm. If you've ever ridden with a slightly loose brake stay arm, you have experienced the situation of lightly applying the brake and WHAM your brakes are full ON with a good clunk. Not good. Brake stay arm probably ought to come off the brake plate ear at 90 degrees (ideal) with +/- 30 degrees from that as probably very workable.
Ed

The brake stay pushing will tend to push on the axle. The brake stay pulling will pull on the axle. ---Clarence

OK, DPO crap. Actually, one I've not seen before. I must say this bike has more than its share. I've had the engine in and out of the frame several times while prototyping but only with the front and top motor mounting bolts. Today I needed a bit more precision and attempted to put the lower bolt in. Hmm, what's going on here? The bolt will not go through. Luckily it's just bare crankcases and it doesn't take long to find the problem.

The DPO had evidently lost the rear alignment dowel and manufactured a new one. The trouble is the mounting bolt won't go through the hole. The engine was out of the frame when I got it and you wonder what size replacement he used or if he even did. I also wonder when he discovered his mistake after he got the engine glued together or perhaps he had a smaller farm bolt ready to go. Who knows---

Max

No wonder you used to beat this guy racing. I suppose you could carefully bore the dowel.

hodakamax wrote:Hmm. Interesting. As you move the axle back as in chain adjustment the brace to prevent rotation becomes parallel to the swing arm and the angle of the cable also rotates forward. A parallel brace should go into tension as the brake plate starts to rotate. By the way, the brake plate is also clamped tight by the axle to the swing arm or at least should be. I'm starting to think our brace is plenty strong either in compression or tension. The force being applied comes down to tire contact to the road. As Bill said, this is a teeny rear brake to start with. I guess I'm the rider, any flaws in my thinking?

Maxie

In tension, failure would depend on tensile strength of the arm. In compression, failure would most likely occur due to deflection or bending. The arm is much stronger in tensile than bending. You might also have a spongy brake feel in compression, and if it did fail, the bent arm could catch and break spokes, hopefully not at high speed but who knows. I would follow industry standard on this one.

Wow, it seems the more I do the more there is to do. I did run down some of my parts scattered around at machine and body shops today, The tank is looking good with dents fixed and primer. The clip-ons worked good after some machining for tube size. The pipe still isn't fixed but I needed it back to check some clearance issues which turned out not to be an issue. Here it is in the most advanced prototype to date. Progress includes 18'' wheels, bigger front brakes, rear-sets started, clip ons figured out and a general shaping up of the concept. Still a long way to go but big fun so far!

Maxie

Embarrassing, but way too funny not to tell. I'm still fiddling with this rear set peg position thing and I need to set on the bike and see if I can even fit on this machine to be created in the road race position. Some of my favorite motorcycle stories involve things like jumping on a bike and the kick start lever goes up your pant leg and as you lean that way your leg is trapped resulting in a very funny tip over, that is if it's not you. Another similar scenario is stopping at a light and your tennis shoe lace has looped over the lever and same deal, a lean with a pinned foot and down you go. Really funny, the more of your friends that are watching helps.

OK, time to check peg position on the prototype. No tires but rear rim. The front is suspended with a tie down from an overhead beam. I'll set on it and check the peg position. What could go wrong? I assume the the full tilt position and even though I'm cramped this may work. Hmm, I'm starting to lean too far to the left and I'll have to put my foot down to catch it. Murphy's law has set in. My shoe lace has made the loop around the peg. Slow motion here. I'm fully aware of the oncoming series of events. I'm thinking that the front is held by the tie down. All true but it's pivoting around the front and I'm crashing a non-running prototype. The bike can still lay on it's side. No bars to hang on to I'm and ejected into a pile of parts along side to inflict maximum carnage. Some blood, all minor, but how many times does it take to convince us not to ride with exposed shoe laces. Duh.

I hope this is not a sign that maybe I should retire from this sport or this is a hazardous machine deserving more respect. All notable. A warning to others I guess. Well, there's the story, I'm sure you enjoyed it being me and not you. On guard!

Maxie

Poor Max! Hope you are OK.
The Beemer has old school carb tickler buttons for starting. The left one is infamous to catch on the pants cuff, and bam, there we go.

I had to watch the Red Toad fall over while on the rack. The handle bars caught it & it just laid on its side, there on the lift. Later, I discovered there was a brand new dent in the chrome headlight ring I had spent so much time polishing! Argh! At least I had another in my box of parts.
So pull the headlight off, disassemble from one ring & reassemble on the other ring & put it back on the bucket.
I'm sure glad I wasn't sitting in her when she went over. Probably would have been a lot more damage! Victor

Maxie, here's me with the bike on the lift table. About two and a half feet off the ground. Bars lashed to the table with tie-down straps. I just mounted the pipe. Why bother letting it down before firing the bike? Right? So I hop up on the lift table and give it a good kick. The right tie-down strap s-hook falls off the eye bolt on the table and the bike starts to tip to the left. No problem. Just take the left foot off the peg and catch the bike...and...uh...TIMMMMMMMMMBERRRRRRRRR. I feel your pain, brother.

Funny, I was just looking for a picture for Victor showing what possibly could clog his pilot jet and I ran across this picture from a while back. Same shoes, same accident. We had discussed this before.

Slow learner

Max

One thing I've learned to do over the years is to swing the left leg up and forward to be sure it hasn't snagged on the carb *as I slow down and before I actually stop*.

I wonder if a "brush guard" would help Max?

Every time I see a picture of max he has new shoes.