Front Brake Master Cylinder

[twigg]

I was thinking of de-linking the brakes on my '86 VR.

 

Does the standard front master cylinder have sufficient capacity to operate both the front calipers, or does it need changing?

 

Thanks

[Keemez]

I delinked & upgraded my 93 with Skydoc's kit. It did make an improvement. I'm not super satisfied just yet with the lever feel- seems to take a pretty hard squeeze to get any serious braking out of it. It's not an air/bleed issue- I'm intimately familiar with all that. I was considering going to a 5/8" master like I thought I had read some others had done. The rear brake operating by itself now is much more touchy- can be locked up at will.

[twigg]

I delinked & upgraded my 93 with Skydoc's kit. It did make an improvement. I'm not super satisfied just yet with the lever feel- seems to take a pretty hard squeeze to get any serious braking out of it. It's not an air/bleed issue- I'm intimately familiar with all that. I was considering going to a 5/8" master like I thought I had read some others had done. The rear brake operating by itself now is much more touchy- can be locked up at will.

 

Skydocs kit uses Yamaha R1 calipers and SS hoses. They should stop you dead.

 

Might be time to find out why they don't.

[dingy]

You should consider going to the 5/8" master on the front.

 

Reason being, you are now driving eight pistons with the delinked brakes on the front master. The larger bore master will provide more volume to push these pistons. You will lose a little bit of PSI by going to the larger bore, but they will lock up under full application.

 

This thread has some info in it on differences between the various bikes in the area of brake sizes. There are several posts I made with different info in them.

 

http://www.venturerider.org/forum/showthread.php?t=44084

 

Gary

Edited April 10, 2011 by dingy

[GaryZ]

I was thinking of de-linking the brakes on my '86 VR.

 

Does the standard front master cylinder have sufficient capacity to operate both the front calipers, or does it need changing?

 

Thanks

 

I de-linked my front brakes using one of the original rubber hoses from the front master to a Kawasaki splitter, then new braided steel hoses to the calipers. The front brake works much better, but, the lever feels soft. This could be the rubber hoses still being used (two more are on the anti-dives) or it could be the front master. I will share when I have figured it out . . .

[CrazyHorse]

I actually left the proportioning valve on the rear I cant lock up the rear after delinking. I have delinked but I still think the brakes on these bikes arent the greatest. Linked or unlinked. I dont care for linking at all a personal choice.

[GaryZ]

I actually left the proportioning valve on the rear I cant lock up the rear after delinking. I have delinked but I still think the brakes on these bikes arent the greatest. Linked or unlinked. I dont care for linking at all a personal choice.

 

I have this same set-up and I want about 50% more rear brake.

[dingy]

I have this same set-up and I want about 50% more rear brake.

I put an MKII caliper & rotor on mine last winter. It will lock the rear up also.

 

If you go this route it will take some McGyvering to get it done The swing arm has a different pin on the MKII's where the caliper mount arm pivots from. The MKI has smaller pin than the MKII does. I ended up getting a rubber stopper and epoxied it in the MKII caliper arm & used it with the MKI swing arm. Held up with no wear over last summer. I have it off right now.

 

The machining was very loose on the MKII parts when mated. At least a sixteenth inch of play. The hole in question is primarily to keep the arm oriented correctly. The axle shaft hole absorbs the braking force.

 

First picture is of the two caliper arms. Red one is MKII. Second picture shows modified hole. Arms are the same length actually, they look different in photo.

 

On the rear master, I pulled the proportioning stuff out and used that hole for rear line. I plugged hole that had went to front brakes.

 

Gary

[GaryZ]

On the rear master, I pulled the proportioning stuff out and used that hole for rear line. I plugged hole that had went to front brakes.

 

Gary

 

Please share how you pulled the "proportioning stuff" out.

Wouldn't it be OK to cap the original rear brake out and connect the rear brakes to the "front" side of the master?

[GaryZ]

I was thinking of de-linking the brakes on my '86 VR.

 

Does the standard front master cylinder have sufficient capacity to operate both the front calipers, or does it need changing?

 

Thanks

 

I live in OKC. I can help with the de-linking process . . .

[CrazyHorse]

Please share how you pulled the "proportioning stuff" out.

Wouldn't it be OK to cap the original rear brake out and connect the rear brakes to the "front" side of the master?

I capped. Yes thats what I did.

[dingy]

Please share how you pulled the "proportioning stuff" out.

Wouldn't it be OK to cap the original rear brake out and connect the rear brakes to the "front" side of the master?

 

There is a picture in the thread linked below that shows the valve gutted.

 

http://www.venturerider.org/forum/showthread.php?t=43598

 

Gary

[dingy]

Here are some other pictures I took.

 

Last two are of a different master, parts are in different order of separation.

 

Gary