brake de-linking on the cheap

[garyS-NJ]

I know there are a bunch of threads on delinking gen1 brakes but I think I read them all and failed to find all details to do it on the cheap..

 

backing up, I bought an '84 xvz12D that sat and the calipers were skootched up. So I cleaned the caliper pistons but having trouble bleeding the unified brake. Oh hell, the front brake feels spongy too.. For the unified brake, I bled the front left caliper by pushing fluid through with the pedal and then I cleaned the rear caliper pistons and tried to bleed the rear.. Using a miti-vac, I pulled pure fluid (no bubbles through the rear caliper but the pedal was still soft). So I went back to the front caliper and it just keeps pulling air through (with the mitivac) like there is an air leak at the metering valve or a line... I mean it was just pumping and bubbles for 20 minutes without hardly adding any fluid to the rear resivour>>

 

I know Earl Skydoc sells a braided kit to delink but I just want to get this old girl on the road to see if I like her to keep.. So I read I could delink by plugging the proportioning valve (to front brake), and then add a second brake line to the front master cylinder and routing to the front left caliper.. I'm wondering if an oem brake line for the front right caliper will reach to the left otherwise how do I find/specify a used or new line? (type of bike or Length and banjo sizing). Oh yes, and I know there is debate as to weather the stock 14mm front brake cyclinder can push two front calipers or if I need a 16mm master cylinder.. Source for that??

 

below rider did a nice job but no details on how to specify the lines and also if the fairing needs to come off to do the couple mount.. I'd rather not pull the fairing.. Never did it, and I told my brother I'd be riding this summer!

 

http://www.venturerider.org/forum/showthread.php?49112-De-Linking-Gen-1-Brakes

[garyS-NJ]

Oh, and I did pop around this sight but didn't see anything about how to bleed the linked system. There was reverse bleeding, and also speed bleeders, and even one guys added a neck bleeder to a first gen. But nothing on a process to bleed a first gen. I did front brake, and then rear brake and tried to do front brake again.. Oh, Oh, and my bleeders were not mistakenly left open nor did I run the resevour dry..

[Flyinfool]

Well to late for riding this summer since summer officially ended early this morning........

 

The master cylinder debate was more along the line of the early Ventures have a 1/2 master which is 12.7mm and the newer Ventures have a 14mm master. The 1/2 inch master is not enough. I have not heard of anyone going to a 16mm master. But I might consider it if I were to find one.

 

There is not a lot of slack in the right front brake line, I would be surprised if it reached to the front left caliper.

 

There are a few places that make custom lines, they have an on line form with places for all of the info they need to make your lines. Banjo size, banjo type, line size, line type, distance between banjo centers, rotation angle between banjos.

[garyS-NJ]

thanks Jeff, can you help with specs on the brake line? or a replacement front master cylinder?? I just found an '87 virago 750 complete bike for parts.. Might I be able to Frankenstein that?? found an ebay virago master cylinder new says it is 14mm bore and 10X1.25 banjo:

 

http://www.ebay.com/itm/Yamaha-XJ700-XJ750-XS750-Maxim-Virago-Vstar-RD-Brake-Master-Cylinder-BLACK-/290906486570?hash=item43bb60b72a&vxp=mtr

[garyS-NJ]

or could I buy this (17mm bore?) and just get the long brake line??

 

http://www.ebay.com/itm/PAIR-7-8-UNIVERSAL-MOTORCYCLE-BRAKE-CLUTCH-MASTER-CYLINDER-LEVER-RESERVOIR-/301729570136?hash=item46407bdd58&vxp=mtr

 

how about rebuild parts for these aftermarket master cylinders?? are the parts available?

[Great White]

any 86+ venture master cylinder will work. I personally would look for the venture master vice other bikes. Mainly because the venture master will support the angles you can get on the handlebars (IE: adjustments). Other masters (for 4 piston calipers) will work fine, but can be a PITA to get level enough to take the cap off without spilling or get full enough for comfort. Brake fluid ruins paint, so I'm fussy about spilling it.

 

If you're just trying to get it on the road cheap to see if you want to keep it or sell it, find a local bike wrecker and buy the front brake lines of any bike that has enough length to fit. There will likely be a single line from the master cylinder to a junction block/pipe and then two lines to the calipers.

 

Some will be saying the used brake lines are a bad idea, but as an interim measure it will work fine. You can even mix a match the older rubber lines if you can't find one that is the right length from calipers to splitter and splitter to master. Copper washers can be reused if still in decent shape.

 

I, personally, would rather replace the rear line than cap it at the prop valve. Even if you use another "scrap yard" line for that.

 

If you decide to keep the bike, change 'em out for some braided lines this winter.

 

You can also get a new line for the rear brake at the same time.

 

If you do decide to keep it, you might consider looking for a set of 86+ forks. The 86+ forks will accept the R6/R1 brake calipers and you can just upgrade and bleed it all once when you put new lines on it.

 

If you want to go that way that is....

Edited September 23, 2015 by Great White

[garyS-NJ]

thanks great white,, good point on the master cylinder angle for handlebars.. But I just found an '87 virago 750 parts bike no title and thinking of buying that just for the master cylinder and brake lines (mast cylinder will probably be humped). Then I'd part the bike (and Frankenstein whatever to where ever... I also have an 83 xj550.).

[lonestarmedic]

I used the front lines and divider block from a Vmax. Then bought 1 new line from master to block. Made an adapter plate for front fork. Block to playe then playe to fork as bolt patterns different. Removed the extra line to the front from the rear. Gutted proportioner block. Left rear line normal spot. Then plugged the front port. I used a rear master cylinder inspection\fill port plug. Right thread and shoulder for a copper washer.

[garyS-NJ]

Just got another honking pressure bleed with my gf pumping the rear brake pedal and got pure fluid coming out the front left caliper... brakes felt a little squishy but good enough (did the back caliper again for good measure). put it on the center stand to see the rear wheel would spin free and brake but observed that the rear caliper was pretty much locked up.. Pumped a few more squirts out the rear caliper thinking the resevour might be overfiulled but the caliper was still frozen so I suspect the relief/return hole in the rear master cylinder (or is that the proportioning valve?) is clogged. try that tomorrow.. but can anyone say if I then will need to bleed the entire unified brake system or just the rear or the front.. also, I understand a proportioning valve adjusting pressure split between front and rear but then what does the metering valve do?? If I plug the proportioning valve and change the front master cylinder and brake lines through a 1:2 splitter, then the metering valve is gone.

[zagger]

My 83's brakes are delinked. For the front disks, I just ran one brake line from the handlebars down to one side and added a second short line out around the fender to the second caliper. I kinda remember that I had to find a double length bolt (or whatever they are called) to attach the two lines to one caliper. Of course, the output from the pedal does the rear. Junked whatever proportioning valves were there (don't actually remember). No big deal - works just like a regular bike with regular brakes. No idea why anyone would want front and rear motorcycle brakes linked in any way if the road surface is less than perfect.

zag

Edited September 24, 2015 by zagger

[zagger]

"Mainly because the venture master will support the angles you can get on the handlebars (IE: adjustments). Other masters (for 4 piston calipers) will work fine, but can be a PITA to get level enough to take the cap off without spilling or get full enough for comfort. Brake fluid ruins paint, so I'm fussy about spilling it."

 

I use the stock master cylinders and reservoirs for the front brake and clutch. Although they sit at an angle due to my non-standard bars, by turning the handlebars all the way left or right, they can be made to be level so that fluid can be checked/added. The lids on the reservoirs seem pretty tight and they have worked fine like this for several years without leaks or problems.

zag

[garyS-NJ]

Is that '86+ master cylinder a 14mm bore (and my '84 linked is a 12mm?)?? I have a line on an '87 master cylinder but ebay has aftermarket MC's at 17MM (pot metal square resevoirs and also the round plastic reservoir).. But then I wonder if I could get a rebuild kit for them.. I also read somewhere the 90's virago master cylinders are good and I remember working on my old CB750 people were upgrading with a Goldwing master cylinder..

.

any 86+ venture master cylinder will work. I personally would look for the venture master vice other bikes. Mainly because the venture master will support the angles you can get on the handlebars (IE: adjustments). Other masters (for 4 piston calipers) will work fine, but can be a PITA to get level enough to take the cap off without spilling or get full enough for comfort. Brake fluid ruins paint, so I'm fussy about spilling it.

 

If you're just trying to get it on the road cheap to see if you want to keep it or sell it, find a local bike wrecker and buy the front brake lines of any bike that has enough length to fit. There will likely be a single line from the master cylinder to a junction block/pipe and then two lines to the calipers.

 

Some will be saying the used brake lines are a bad idea, but as an interim measure it will work fine. You can even mix a match the older rubber lines if you can't find one that is the right length from calipers to splitter and splitter to master. Copper washers can be reused if still in decent shape.

 

I, personally, would rather replace the rear line than cap it at the prop valve. Even if you use another "scrap yard" line for that.

 

If you decide to keep the bike, change 'em out for some braided lines this winter.

 

You can also get a new line for the rear brake at the same time.

 

If you do decide to keep it, you might consider looking for a set of 86+ forks. The 86+ forks will accept the R6/R1 brake calipers and you can just upgrade and bleed it all once when you put new lines on it.

 

If you want to go that way that is....

[Great White]

http://www.venturerider.org/forum/attachment.php?attachmentid=39900&d=1262559319

[garyS-NJ]

thanks great white..

 

so the 14mm might do two calipers and the 16mm most definitely will do?? I'm going for the brake line today.. gonna just run one more line from MC to the right caliper.. I don't see the logic to buying three lines and a splitter (even though I have a Honda splitter downstairs..).

[Great White]

thanks great white..

 

so the 14mm might do two calipers and the 16mm most definitely will do?? I'm going for the brake line today.. gonna just run one more line from MC to the right caliper.. I don't see the logic to buying three lines and a splitter (even though I have a Honda splitter downstairs..).

 

 

14MM runs four piston calipers already on the 86+ models.

 

Well, 6 pistons total I guess if you count the four piston front and 2 piston rear.....

[garyS-NJ]

whoa, another goodie I forgot to close here.. My binding rear caliper was not due to piston/pressure but rather orientation of the caliper itself on the rotor..

 

first I bled it a few squirts but that didn't help so I figured the piston was stuck and when I loosened the caliper bolts, the wheel spun freely.. tighten the bolts, the wheel wouldn't spin.. somehow the caliper was binding because it's not aligned with the rotor.. then I guessed that the washers on the shouldered caliper bolts (only one set of bolts had washers so I put them on the back) might belong between the caliper and the mounting bracket. well one fit there toward the rear but not on the front (looled like I might fit 1/2 the thickness). but I bolted it up that way and it spun fine last night and didn't get hot enough to bind the caliper.. Oh, and the rotor is spinning true with respect to the caliper.. GOD!

[syscrusher]

That's odd, at least from the perspective of a gen 1.2 owner.

I wonder if your bracket is slightly bent or misshapen.

My rear brake didn't perform satisfactorily until I put HH pads on it.