Topic: For all you custom building guys I need your help and ideas

[SOHC4 Cafe Racer Fan]

You could always run a linkage system under the bike and have a rearward facing pedal on the left. This may be a problem if your looking to downshift while in a corner. You may loose efficiency in a linkage system however, due to imperfect joints etc. Just a thought

That would require a fair bit of dancing between the rearward facing foot brake and forward facing shift lever. Cool idea though.

[calj737]

Yes, but what year 750 had disc brakes and spokes?

1976 super sport for instance.
[/quote]
Excellent! That makes it much easier-

[scottly]

How about a foot-board on the right side instead of a peg, and a cable actuated pedal similar to a car, except it would be pressed straight down. Think you could manage that, Jim?

[springer]

my real big problem is the prosthetic leg weighs about 8 pounds so lifting it straight up seems to be difficult I should have a new leg coming next month and I'll get to see how heavy it going to beplus I haven't been able to wear my other one my knee is swelled so bad I can't get it on Jim

[70CB750]

I think long term solution is to bypass the prosthetic leg and have all controls via your other limbs.

Did you try to do some search, here is a bunch of links:

http://www.mtb-amputee.com/motorcycleamputee.htm

I will be happy to help you with ideas and realization, but most likely somebody somewhere already has a technical solution we can duplicate.

[springer]

well that is one heck of a link I'm going to read through this and see what I can find thank you very much jim

[springer]

and I read through a lot of the motorcycle amputee for the legs 98% of them are the left leg wish mine was the left leg.would be a lot easier I'll just have to keep reading man there is a lot on this link thanks 70CB750 Jim

[Cqyqte]

Most of the applied forces are required for the front brakes the trick is to limit the forces being sent to the rear.  I know this sounds crazy but it works, in the rear hydraulic line you use a restricter similar to that used in carb jetting, it takes sometime to figure out the best ratio but it works.  If you want more adjust-ability you can use a brake proportioning valve from Jegs http://www.jegs.com/p/JEGS-Performance-Products/JEGS-Adjustable-Proportioning-Valve/755192/10002/-1?itemPerPage=90&pno=1 and mount it up on the handle bar for weather condition (rain, sandy, winding road/city) adjustments.

Jim has been having issues with his prosthetic leg.  I'm uncertain as to the extent of function he has with his right lower leg.  Is the combined braking system you were suggesting something you might be able to assist with design and fabrication? ? Valving the rear brakeline pressure sounds like a touchy balance -- to much and you lock up the rear under heavy braking.

Yes anytime you start playing in a safety system arena you are definitely dealing with a touchy balance.  You definitely cannot go into it blindly, and alot of research prior to dynamic testing is necessary.  Provided one realizes the risks and proceeds carefully successful goals can be reached.  Think about custom set ups from the past, suicide shifters, electronic shifters, modifying dual front brakes to single set ups, forward brake to rear set.... on and on.  Each new concept was imagined, primitively manufactured and then tested before finalized and made mainstream.  The key is "tested intelligently" when the result is unknown you must proceed slowly and be prepared for surprises or unpredicted results.

The joining of front and rear systems is easy with a simple "T" union, but restricting the rear pressure is hit and miss until you zero in on the range of control that provides the best front rear bias for the majority of circumstances.  As I have created a primitive front rear biased system using jetting style restricters, in this case I would recommend the use of a manufactured adjustable device from Jegs or Willwood.  Willwood offers one that is metric and would be a good choices for this situation.  Pricing isn't too outrageous and the modifications to the CB550 rear drum brake linkages could be quite simple saving even more costs.

[springer]

well guess I'm going to have to scrap the 550 and buy me a Harley Davidson an oil leak and vibrating just can't do it I love my 550 all these brake conversions are all on Harley Davidsons Jim

[Cqyqte]

Here is a relatively in expensive push style slave cylinder, http://www.speedwaymotors.com/Push-Type-Slave-Cylinder,1944.html, which could be positioned to push the rear brake linkage down in a similar fashion as the human foot would.  Couple it with the adjustable biasing proportioning valve connected through a "T" adaptor and you have all the pieces to make a combined front/rear proportioned braking system that will work on a 1975 CB550.

[strynboen]

somthing like this can do chlutch and rear brake  in one handel

..just veld a kabel att on the rear hub..and make a mod arm for kabel

..then you can move the gear shift to the best side..by use linkage from a 400 four..it can easy be fit to a 550..this all can be made for lov buged..and vork

just adjust so chlutch  pulls at start,,and brake goes inn at mittel to end of movent...you vill then pull the chlutch evry time you brake..but that is not a problem

http://www.ebay.com/itm/1987-Yamaha-YFM80-Badger-front-brake-right-lever-handle-dual-cable-mount-perch-/161492099836?pt=Motorcycles_Parts_Accessories&hash=item2599ade2fc&vxp=mtr#ht_1281wt_1362

[rb550four]

I haven't got out to the shop to try anything out for you but,
I'm thinking use your wheels, flip the brake lever on the rear hub to the up position , instead of down. run the brake rod over the swing arm,weld in a new pivot point from the  stock brake up near the Y just under the side cover, and manufacture a comfortable padded stirrup type lever that you can push or pull with what is left of your right leg.
  Sorry about your leg, we need to get you back on your machine, and this route seems doable to me. Let me know if I missed anything and if it's a stupid idea.Not to be unfeeling , does your leg stop at,above or below the knee?     This may be a the most worth while reason I have to hit the cold,cold shop .

[rb550four]

Okay, so it's like 12 degrees, and I'm willing to get in the cold cold shop to make some parts and see what works best.
  There has been some talk about using an F frame and then I saw something about switching over to a K frame. Which frame are you going to run? I want to make it right on on  that frame...doesn't matter which one, I have both sitting here, just has to be the one you are going to use if it's going to work for you. Take a pic of the frame you will be using so there is no mistake please.
  Then, I need to know how much leg you have left to use, that's why I asked ,above , at ,or below the knee. So I can kind of calculate where everything should go.
  I'd like to make some parts  and send to you when done to see if they'll work, you don't have to use them if you don't want to, and won't cost you anything. I just want to do this.
  If that sounds alright to you, just answer the above questions and I can get started.

[calj737]

RB - Jim's surgery was below the knee.

[rb550four]

Thanks Cal, I just talked to him on the phone. Amazed how sh1tty  stuff always happens to good people, but he has a great attitude.
  It's good to know that you are working on a hydraulic /rear rotor solution.
I was working on a thigh operated mechanical setup similar to rearset shifting mechanism but it'll get crowded fast around the brake pedal /kickstart area...he already has pedal clearance issues with the stock 4 into 1 for some reason.
   Now I'm leaning towards trying a thigh operated cable system , cable-stays welded onto the 550 swingarm with remote mechanical actuator that bolts on a plate just below the sidecover,( on the 2 bolts that fasten the upper engine mount), so he can stay with 550 rear parts (so's not to cut or weld strange things to the frame, only the swingarm,just remove the brake pedal and rod and bolt it in).    My homework is to find out which bikes used to run a similar system and check with motion pro about a cable .. I'd be happy with any solution that works for him.
    And I think a rear disc alternative for a 550 would be very exciting for any of us.Keep us posted.

[SOHC4 Cafe Racer Fan]

I think this is a project that we all want to succeed.  We all love to ride, and to make sure that Jim keeps that enjoyment is a WIN for our community.  It it's a matter of used parts, let's see what we can contribute. If it's a matter of $ for fab or new parts, let's put it together if needed.

Many thanks to Cal and rb550four for contributing their savvy.

[springer]

you guys are building with out me so here a pic of how short my leg is  if it help and the bike is a 1975 cb550F Frame. a 77 swing arm 77 front end 77 motor thanks for everyone help Jim

[NobleHops]

If somebody clueful is up for taking the lead on engineering a solution, I've got $50 to kick into hardware or services. Anyone else?

[SOHC4 Cafe Racer Fan]

I'll kick in some financial support, too.

[Garage_guy_chris]

Don't let it get the better of you. There is a solution out there.. I scanned through the thread and a rear disk brake has been discussed at some length. but what about just making it a combined system where the front master is tied into the rear brakes aswell, im sure you would need a proportioning valve of some sort but i would think its quite doable.


Heres some inspiration:



http://www.motorcyclemuseum.org/halloffame/detail.aspx?RacerID=124

[springer]

This great. Story Really enjoy reading it Thank you Jim

[calj737]

Exactly what Chris is proposing is under development. Using a twin rotor MC and a proportion ing valve so the ergonomics are a single hand control to link the brakes. No other modifications to foot pegs, or cables... Bike will then appear stock and Jim won't have to "learn" how to ride any differently than he ever has.

I'm working with a machinist to develop a drum-disc adapter using our stock hubs. It will be a bit of time before I get too far due to the weather we've had here, but I know Jim is also pretty weather stuck too and targeting late Spring. The only design consideration to deviate from "stock CB" is whether a CB rotor and caliper are used. There's smaller and lighter units out there, but I know Jim prefers stock looks. Could use a 750f as a donor or 750ss as Prokop suggested too.

I'll post some updates as enough progress is made.