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

[springer]

most of you know I had right foot amputated. I think I'm going to have a problems using artificial leg, so some options might be nice so I need to use my left foot to break with so I need help with a custom pedal on the left plus keep my shifter or a way to use a hand break on my rear brake. oops 1975 cb550f thanks jim

[SOHC4 Cafe Racer Fan]

Jim,

Can you get by with just front brakes?  This would be the easiest way to go OR to go with a dual disc front so that front only brakes would give you plenty of stopping power.

Configuring a hand-controlled rear brake is doable.  I have seen it on race bikes: Tom Sykes uses one on his Kawasaki ZX10 in World Superbike and Mick Doohan used to use one when he was a GP racer.  You can set up a rear brake thumb-lever for your left hand for the rear brake.  It will allow you to simultaneously use both front brake (using the conventional right lever), rear brake (using the left hand thumb lever) and use the clutch with your left index and middle fingers). 

The one Sykes uses looks like a paddle:

http://www.superbikeplanet.com/image/archive/sykesthumb/sypad2.htm

To do it, you would need a thumb master cylinder and a rear brake disc (such as one off an F model).  This would NOT be a cheap mod.  Brembo makes a racing billet model (http://moto.brembo.com/en/detail/X985770) that is ONGODLY expensive -- around $2K.  GPTech used to make one but it's not cheap either (around $400), but will not require you to give up a kidney (http://www.demon-tweeks.co.uk/motorcycle/thumb-brakes/gp-tech-billet-handlebar-mounted-thumb-brake).

Mike LaFountain (Raccia Motorcycles in California) also used a cable-actuated rear brake on a CB550 build, but that would still require a second brake lever for the rear -- and he did not use the stock rear brake, but some type of twin-leading shoe.

[InAquaVeritas]

Sorry to hear about your foot! I hope you will find a good solution to ride easily.

There is a system called the combined braking system, which works like a car does. Both the front lever and the rear pedal operate both brakes. If it is legal you can remove the foot brake and rely on your lever for both brakes.
http://en.wikipedia.org/wiki/Combined_braking_system

Another option is to go left foot clutch, left hand rear brake and suicide shifter or, if you can fabricate it, something like an old school Vespa. They have the gear select integrated into the left hand controls/clutch.

A shame about the lame tattoo (or does anyone have 1 down, 4 up tattooed on their left ankle..), but the best pic I could find that shows it.

[SOHC4 Cafe Racer Fan]

Sorry to hear about your foot! I hope you will find a good solution to ride easily.

There is a system called the combined braking system, which works like a car does. Both the front lever and the rear pedal operate both brakes. If it is legal you can remove the foot brake and rely on your lever for both brakes.
http://en.wikipedia.org/wiki/Combined_braking_system

Another option is to go left foot clutch, left hand rear brake and suicide shifter or, if you can fabricate it, something like an old school Vespa. They have the gear select integrated into the left hand controls/clutch.

A shame about the lame tattoo (or does anyone have 1 down, 4 up tattooed on their left ankle..), but the best pic I could find that shows it.

InAquaVeritas,

I think Jim is looking for something he can integrate affordably -- rather than developing a technology for his CB.  I don't think he can integrate a combined ABS system from a modern bike or the Vespa twist shifter. 

The most cost effective solution would likely be dual discs up front with an improved master cylinder. 

The rear thumb brake exists but is almost certainly too costly to use.

[calj737]

Use a heel activated rear brake relying on a rear disc brake, actuating the rear via a master cylinder.

Biggest trick is to somehow integrate a rear disc with spokes for your wheel.

[754]

Easy to build rear disc hub. Using a front hub and spacers as long as you are not dumping huge hp and burnouts thru it.

[FunJimmy]

Wouldn't it be easier to put a 750 rear disc wheel and swingarm on it?

[calj737]

Wouldn't it be easier to put a 750 rear disc wheel and swingarm on it?

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

754, adapting a front hub to the rear, how do you address the Cush drive?

[Nayl]

75-76 F models have rear disc with spokes

[NobleHops]

Wouldn't it be easier to put a 750 rear disc wheel and swingarm on it?

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

754, adapting a front hub to the rear, how do you address the Cush drive?

Ya, this sounds sketchy to me, no offense.

As others have pointed out, a hydraulic solution for a thumb brake is likely the path of least resistance, if you can find a disk brake wheel that will work and not look like #$%*e. This stuff looks super trick, there are likely others:

http://www.beringer-brakes.com/en/moto/technologies/thumb-brake-16.htm

I'd probably forego it altogether as was suggested and spend the energy on making the front brake all that it can be.

Sorry you lost your foot.

N.

[Cqyqte]

Sorry to hear about your situation, but I have built systems similar to some of the high end new touring bikes with combined front and rear braking systems, that may give you a answer to your predicament.  I have not thoroughly read the thread yet but if you are working with a hydraulic braking system or if you could switch out for one the system to combine front & rear is pretty simple. 

[NobleHops]

Sorry to hear about your situation, but I have built systems similar to some of the high end new touring bikes with combined front and rear braking systems, that may give you a answer to your predicament.  I have not thoroughly read the thread yet but if you are working with a hydraulic braking system or if you could switch out for one the system to combine front & rear is pretty simple.

Could I trouble you to elaborate a bit on what makes this simple/doable? Not being snarky, just interested. Parts used, photos, would be super valuable content. TIA.

[Cqyqte]

I see you are working with a CB550, adding a hydraulic rear brake cylinder to activate the rear drum brake is quite possible using the OEM pivots and a the rear brake pedal (modified of course).  The best rear brake cylinder to use would be one off a 1975 CB750 as it's orientation is right for this type of modification.

[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.

[754]

750 frame brake/arm is heavier wider and shorter.
 Using front hub on rear, you get no cushion drive, but people do make small ones now.
 Just suggesting a possible  budget solution
 The front conversion was used a lot in the 70s,  in fact C and G made casting that made those hubs out of one piece so you did not need to add spacers.

[SOHC4 Cafe Racer Fan]

One of the crucial factors for Jim is the cost of the solution, too.  If we can get a cost-effective solution or one that someone can help with development, we would be doing a solid for Jim.  After all, Jim doesn't need a pretty paperweight but a bike he can ride safely.

[SOHC4 Cafe Racer Fan]

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.

[strynboen]

i had (for some years ago) a doubbel cabel magura handel for cabel front/ rear  kabelbrake. use it on my pit bike garelli katia/mz 150 kombined..vith no brake pedal

..but it can be made to chlutch/rear brake kombined..its 2 step so pulling first chlutck ..then  rear brake,, it can be rideabel..it need some gearing to pull a brake shue..but can be done by a reaktion arm..gearing dovn the moving 1/3 so pulling gets easyer

edit have seen it on china atv,,,so it still in buisness

[springer]

Maybe I should just try and find a cb550 trike or a cb750A trike but I hate trike if you cant ride on two wheels get off the road. I was at the doctor's today and was looking at the table that was in the other room it was stirrup table the foot holder look doable or making it work

[strynboen]

no dont go trike.
.you have balance. or vill get it latest by this summer.and the rest leg vill be better/stronger..by time.(.i now it are soft and hurts.).even just to traning to valk..but after some time it vill be more easy..and fun vill begin..one of my frends got his leg in a asfalt road build machine/truck.he can use mine mc vith care..
 still think a doubel grip vith clutch/back brake..in one kombined grip can easyst and thepest be made.

.hydralik dubbel systems ,almost need to be abs to balance the braking power..but yes it are done bu only a balance valve..but still no rear disc..make it kosty..on a old 750 or 550..

[calj737]

sit tight, Springer. Ideas are in the works...

[springer]

guess I should have waited before buying new rims for my bike now I might have to change my rear rim to accommodate my right leg being gone, maybe I can find me a fast moped. what a pain This is should have thought about not having the leg before I started redoing my bike I appreciate all your help so many knowledgeable people here wow did I spell that right is that even a word oh well lol Jim

[SOHC4 Cafe Racer Fan]

sit tight, Springer. Ideas are in the works...

I love it when a plan comes together. 

[70CB750]

Wouldn't it be easier to put a 750 rear disc wheel and swingarm on it?

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

754, adapting a front hub to the rear, how do you address the Cush drive?

1976 super sport for instance.

[Lammers000]

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