Hi folks, I joined up specifically to ask about the brake system on the Blackbirds. And I hate using the term 'disabled rider' - I prefer "My left arm doesn't work" I'm hoping I can get some responses for my project. I'm currently riding a 2000 Honda VTR250 and it has the traditional braking system (front lever to front, foot pedal to rear).

Since I ride only using my right hand, I have my brake lever and clutch lever setup in tandem on the right bar. Of course, throttle is still there. So, my hand is fairly busy. I would like to link the front and rear brakes using the footpedal running an independent line from the remaining lever to the rear brake. I know, travesty! A lot of folks on the board here are delinking brakes for their preference. But please forgive I'm also concerned in an emergency situation that my hand will not be applying enough braking force as it is also busying grabbing the clutch and holding the bike and myself upright (whatever weight my legs and core don't hold back). Currently, I apply too much rear brake and lock it up, which will get me into trouble real fast.

In order to run this setup I was looking at a 3pot rear caliper with dual inputs (ST1300, GL1800, CBR1100XX) and a proportioning valve off the pedal MC to bias the majority to the front. Well I came across several Blackbird linked brake systems for decent prices and am thinking of purchasing one, as that is cheaper than buying all new individual parts. I would use the rear caliper and proportioning valve for sure. And possibly the MC depending on the needs of the system. My front caliper is a 27mm dual pot and stock rear MC is 1/2".

1. Does anyone know the measured proportions (and diagram of which outlets are which) the proportioning valve is set for? One system I'm looking at is a '99 the other an '01.

2. What size is the rear pedal MC? From the blurry pic, I gathered it was 11/16", is that correct?


I'm unsure if I will need to use a larger MC than 1/2" or not. I'm also undecided on which of the pistons in the rear caliper to use for each braking function. For instance, should I use the single center pot in conjuction with the front brake for the linked setup? Or should I use the 2 pots in conjuction with the front brake? I do still want an individual rear brake and that will use the 2nd input.

I hope you guys don't mind the intrusion. I'm wanted to come straight to the horse's mouth for information on the Blackbird brake system. Riding season is closed and doesn't start up again until April, so I have time to do projects.

I think you may be setting yourself up for an over braking situation. The calipers are designed for a bike that's 3 times as fast and twice as heavy.





I have a 400 hondamatic I'll trade you for the 250. no clutch to deal with.

What about eliminating the rear brake altogether and running a line from the rear M/C to the front calipers.


I have a complete line set here taking up space if you're interested.


Where are you located?

OK, I can give some ideas to work with.

You could go with one larger rear master cylinder (mabe from a heavier bike or heavy cruiser that needs more back brake), come out of that to a y fitting to the front and rear brakes. In the line to the rear you install a brake bias valve, they are about 70 to 150 bucks i think. This valve has a knob on it that allows you to reduce preasure on the output by an adjustable percentage usually up to 50 percent . Most car speed shops have this a valve , cause when you mess with oversize brakes on a car you need one. The the one I have in my 5.0 is from ford motorsports(re bagded from baer i think), its not that big and there would be room on a bike, but you will have to mess with fittings . I would put it somehere it easy to get to so you can get it set up right . The problem with this is if you have a leak you loose both front and rear brakes. I run my 5.0 on the track like this but i still have the emergency brake though at 100mph into a hair pin it the E brake would most likle just make me run off backword instead or front ward

The other and maybe safer, since you have redundacy , is to hook the rear petal to 2 rear master cylingers , then by varying the linkages you can adjust the bias. This set up of 2 mater cylinders is used on some race cars maybe a lot im not sure.


I think the key is build some bias adjustability into you set up as you will be mixing and matching components and IMO you will never get it righ the first or 5th time unless you can adjust it .


Herb

Welcome aboard, and thanks for considering our resources to address your needs.

I find this interesting for a variety of reasons, one of which is that I was considering this concept just a few days ago, and had ruled out using both traditional clutch and brake off the throttle hand.

Your project certainly seems feasible, but just seems like too much work. Have you considered the use of a thumb brake on the throttle side instead of the traditional lever? That way you'd have your fingers on the clutch, thumb on the brake, and wrist on the throttle. Busy, but it would seem more manageable than trying to run both clutch and brake from traditional levers.

The proportioning valves changed in '99 when the amount of rear bias was decreased, but I'm not aware of any publication of the actual bias. Perhaps in an older road test or press release, but I don't recall ever seeing that information.

Hi guys, thanks for the thoughts. As for trading this VTR for that 400, not a chance! I love this little Vtwin Though, hopefully in a year or so Aprilia will have brought the Mana 850 to the States which I'm hoping will be my next bike.

We are currently stationed in Japan and will be for the next couple of years.

Dion



Right. But which calipers are you talking about? I only need the rear caliper from the Blackbird. Do you know the sizes of the pistons? (edit: I found the parts pdf and size is listed there) As I mentioned, I'm unsure which of the pots to use for the the setup. I was thinking for linked duties with the front, use the center pot. For the independent rear, use the the remaining two. Will that setup still be too much? Under normal braking, I would not touch the lever on the bar. The only time I would would be to hold the bike at an incline or rear only duties. Side note, I see you're in Rochester NY. Have you been there long? My husband is from there.


airbornexx


I have a single disc rear and single disc front. I would like to keep the rear brake. I've found that without it, the front dips forward a little more than with. Any help keeping the bike settled I'm gladly taking.


HERBXX, I know exactly the proportioning valve you're talking about. I shot an email off to a custom bike builder asking about a project where he linked through the pedal as well. He said he used a Jegs brand valve, as it was small and easy to hide and adjustable. You're right that it won't be correct unless it can be adjusted.


rockmeupto125, this tandem setup isn't tough to run per say. My husband rides my bike and he was able to pickup the mechanics of it pretty quick. You know, I hadn't considered the thumb brake much. When I was initially starting the project, I had the clutch on the thumb. That turned out to be a bad idea. I ended up dropping the clutch and bouncing off the front wall of the garage Needless to say, I'm a bit soured on thumb levers lol Actully at this point, finding the room for a lever to operate is tight. I did do a little visual check on that when I was considering using a thumb brake for the hill holder/gravel brake for the independent rear. I'm concerned that there's not much room as I have rotated the throttle housing forward in order to have the throttle cables exit downward. This provided room for the clutch lever to have full range of motion. Now, stream of concious says, if I removed the stock brake perch, I can place the clutch perch more level on the bar, thus rotating the throttle housing back to original position and have room to run a thumb brake.


Guys again, thanks for the ideas. I'd like to hear more. Like I said on the brake system on ebay, I'd only be purchasing the set as it is cheaper than buying and finding individual parts. I wouldn't actually be using the whole system on my bike. I would for sure use the rear caliper (is it really too much braking power?) and the proportioning valve to bias to the front. Is my 1/2" MC adequate to push the center pot of the rear and the front 2pots (of the stock caliper)? Is this idea really not going to work?


Oh, if you have a little time, I've got pics and vids in my blog story of the bikes and the setup: http://www.totalmotorcycle.com/BBS/viewtopic.php?t=17150

Shorts... I'm impressed

Please stick around and keep us posted on your progress.


Oh and I want that VTR 250

Thanks Brett :)

I used to have a VTR996, Super Hawk. Never seen a 250, very cool. You are pretty amazing too! Keep up the good work.

Thanks for the link, Shorts, and due respect to you for your perseverance.

I don't think too many folks here are really up on what bore sizes will work with multiple difference sized pots. I certainly am not. You can do the math to see if it will theoretically function, but a lot of it is in the feel and travel experienced, and that's a function of the leverage curve provided by the individual lever/master cylinder bracketry. That's pretty deep into engineering, when the only viable answer is that you'd have to try it to see if it works, which is a lot of work, and a lit of "if." There's nothing wrong with the idea....a brake system is a brake system, and fairly simple...but voodoo alteration of the XX system is something that most folks here haven't done. We have some really smart folks here who could do that stuff, but its just not an application in which modification or experimentation is popular or needed by most folks with the XX.


That's why I recommended the thumb brake. It allows your braking system to remain nearly all stock, with the exception of the master cylinder, minimizing the potential problems that may/will surface. I'm surprised you considered the thumb clutch at all...its completely contrary to how your body works, as you have already found out. When releasing the clutch, you need your strength, and therefore fine motor control, at the outer end of the release....when your thumb is greatly extended, altering your grip on the bar and at the weakest point of your thumb's range of motion. Its a recipe for error, as you've found. Using your thumb for the brake, however, uses the natural strength and ability you have in that digit. The brake requires light pressure at the beginning of travel, and increasingly greater strength and sensitivity for modulation and control as you increase braking force. It works very well, and naturally. Think about it. As for room on the handlebar, if you really need it to fit brackets and levers, I'd suggest you consider a custom switch housing that might be more compact than the Honda OEM, and give you more working room.

XX brake parts are frequently available used, and I'm sure folks here would be glad to try to help as well if you decided to continue on that path. I'm simply suggesting alternatives that might be more easily accomplished. If your heart is set on the linked system....you'll find a way to do it...it just might take longer.

The front and rear are the same on the bird. The two outer pots are for normal braking and the centers handle link functions and are slightly smaller than the outers. I mentioned over braking because you said you have problems sometimes now with locking the rear wheel. Using the bird caliper with the two outer pots and larger pad surface area would be about equivilant to putting a second stock caliper on the bike and could make it more prone to lockup.

Borrowing from Brett, Herb and Joe's ideas......

Why not get some custom lines made. Use the rear master to control the front brake with a second line running through a proportioning valve to the rear also. Then run an additional line from a thumb brake to the rear caliper. This would give you a link function for normal braking and the ability to apply more pressure when needed and clean up your right control. Minimal investmant and easy to reverse if you don't like it.

I was born and bred in Rochacha. It would funny if your husband and I knew some of the same people.

Tim, the 250 is like the bird. Another bike that Honda dfoesn't bring to the states anymore.

rockmeupto125, good thoughts on the thumb brake. The thumb clutch wasn't the best idea I've had I'm going to keep the thumb brake in mind.





Dion, this is the original plan, and you nailed it. It would be the simplest configuration. When I asked about that setup on another board someone mentioned that I would not be able to place two separate lines(MCs) into one caliper as the system would never be effective. What would happen is you'd just push fluid from on MC to the other. It was due to that that I decided to look for a rear caliper with 2 inputs so that I have two closed systems, rather than one. What do you think?

Overall, above schematic is what I want. I don't think everyone understands that judging from the responses I have received. The ONLY reason I would be using Blackbird parts is that they are available (rear caliper for the dual inputs, the proportioning valve, and maybe the rear mc). I don't want or need the complete front and rear system put on my bike, merely factory parts that are readily available to do the above link.


Good thoughts. Ultimately, the brakes need to be safe. There's no other way around it. By doing this, I'm hoping to make the task of braking, and overall riding a bit simpler considering. Thanks for support! :)

Figures, the 250 looks like a fun, commuter bike.

Is the Blackbird's proportioning valve adjustable at all? If not, it'll be better to go with an aftermarket adjustable unit so I can get it as close to where I need it as I can. I will still need a rear caliper and bracket, possibly a larger rear MC. And to keep this complicated, I'm thinking a delay valve to the front caliper. Does the placement (closer/farther) from the caliper make any difference?

Well, it seems that nothing on paper is for sure and the only way to find out is to build it and see how it goes. Scarey thought throwing money and work for an unknown


Thanks guys for the help

The XX proportioning valve is not in any way adjustable.


The distance from the caliper of a delay valve or proportioning valve is inconsequential in the small distances necessary on a motorcycle.


"Well, it seems that nothing on paper is for sure and the only way to find out is to build it and see how it goes. Scarey thought throwing money and work for an unknown."


Pretty much my thoughts. Its certainly doable, but I'd push you to try to stay as stock and simple as possible to get the task accomplished. You're not trying to build a one-off custom ultimate farkle. You're trying to make something that works.

You're right, KISS. I often must stop myself from complicating a project, start over and say "Ok, I just need to connect X to Y"

Shorts,

I'm not much of a mechanic, so I can't offer you any advice on the technical matters
of converting/using the 'bird's brake system for your use; you are in good hands with
the very knowledgeable folks on this board. I had to say, though, that your story is
inspirational and I thank you for sharing it.