I delinked the brakes on my '96 cbr1000f a few weeks ago and I've noticed that with the front brakes when you pull the lever I wont feel hardly anything and then then suddenly just grab. I can't remember how much play I have before they'll grab but it's enough that it just doesn't feel right, and then them just suddenly grabbing can catch me off guard at times. I've not drilled the calipers to run on all 3 pistons (just running off the top and bottom pistons) just because I wanted to see how it felt like that at first but I've read from where others have had the same issue with there's even with them drilled to run off all 3 pistons. I've bleed the brakes enough times to know for a fact that there's no air in the lines. My other issue is my back brakes almost feel non existent. I've tried running off just the center piston and then switched it up to run off the upper and lower pistons but nothing seems to change. I can stand up on my back brake lever and still barely slow down, I don't use them much at all but I like knowing that they're there in case I need them. I put a new set of brake pads on the back, checked to make sure the pistons were moving as they should and nothing was frozen up, but again nothing. The only thing left that I can think of would be the rear master cylinder, but I figured I'd ask first and then spend the money I don't have haha

 

The linked brakes are notoriously difficult to bleed, that may still be your problem (glad I don't have them).

How were they before, did they work well? If so then it's a case of going over what you've done to change the way they perform.

 

well it's setup just like a basic brake system. for the front there's the line running from the master cylinder which splits into 2 lines going to either caliper on the front working the upper and lower pistons on each. The secondary master cylinder is removed and the front left caliper is mounted to were it needs to be without the secondary master. The rear is just the brake line running to the caliper working the upper and lower pistons. I removed the second line that ran to the front from the rear master cylinder and replaced the extra long banjo bolt with a regular length one for just 1 line. The proportional control valve is removed along with all the extra lines. Now I just bleed the lines like a normal system, there's nothing running from the front brakes to the back brakes and nothing from the back brakes to the front brakes so they work independently. They seemed to work ok before but I wasn't able to get the bike legal until about a week after I delinked the brakes. I've got a half mile of paved road I can ride on at my house without cops bothering me so I could kinda test things out but the couple corners there are I would mainly just down shift on, it's not until I got out on the road hitting corners alot quicker that I really had to use the brakes. I plan on replacing the front brake lines with braided stainless steel lines so that'll probably help some since they won't expand line stock lines. My biggest concern is the rear brakes since they're almost non existent but I can get a rear master cylinder off ebay for $20 so I wont have to spend alot of money or anything. The rear master cylinder on linked brakes is made to work 3 pistons, the center piston on the rear caliper and the center on both fronts. now that it's only pushing fluid to 2 pistons thru 1 line may be messing with it some, I could be way off, but for $20 I can get a rear master cylinder for a '90 cbr1000f which had 2 pistons in the rear caliper. In my mind it makes sense that it may work better since it's made to push fluid thru 1 line for 2 pistons. It looks like it would mount right up no problem but if it doesn't I can fabricate a bracket to make it work no problem. Do you happen to know if anyone makes a rebuild kit for a master cylinder? I know I've seen rebuilds for calipers but don't remember seeing one for a master cylinder

 

Check the caliper pistons for sticking - that is one of the biggest causes of grabbing brakes.

You apply pressure at the lever - then suddenly you have enough pressure to overcome the sticky pistons and they grab the disc.

The amount of fluid actually moving when using the brakes is no where near enough the give you a flow issue ( I work in pneumatics & hydraulics ) - so one line or two lines is irrelivant.

Before you spend any more money - use the two hoses to the rear caliper and feed all three pistons.

 

And also note the way Dean0 has laid out his reply.

So much easier than a wall of text.

Don't be afraid to use the enter key between random thoughts rushing into your brain.

 

my issue is i have to type quickly before it leaves my brain, ADD sucks haha

I'll try to get myself into the habit but i can't promise anything.

The only issue I have with using another brake line is the ones left over are WAY too long to put on and then go riding down the road.

I've replaced all the brake pads and when I pulled the calipers I checked ever piston, even the center in case I decided to drilled them to link all 3 pistons together and there were no issues with them sticking.

I'm going to go thru all my extra brake lines today and hope that I have one short enough to work. If not I'll check with my uncle, he's always got a ton of random spare parts laying around. Thanks guys, I'll keep ya updated

 

Are we talking about the original rubber lines here?

 

yeah, work's been slow due to all the rain over here on the east coast so I've not had the money to get the braided stainless steel lines like I want, or the jet kit I need.

 

Last time I was in N.C. about 2006, you guys were having a drought.

As far as your brakes are concerned. See all of the above

I remember reading somewhere in the service manual that the rubber lines should be replaced every 4 years..

I'm going to theorize here.

The linked system might have compensated for old and bulging lines by using both brakes front and rear at the same time.

To stop in the same distance unlinked, I'm thinking, might require more rider input via the levers and the old lines aren't quite up to snuff. After taking up the slack for the bulging lines, the caliper then responds to the increased rider input and then they grab.

I certainly understand budgetary constraints and even though braided lines are the best way to go, replacing the old rubber lines with new rubber ones at a lesser expense will make a world of difference

 

well I can get a set of braided ss lines for the front for less than $100, and i think around $45 or $50 for the rear but I need to spend the $60 and get a jet kit first.

I would think the ss lines would help significantly with my issue on the front since they're not going to bulge like rubber lines.

If this rain will slack off again I'm going to hook up the extra line I've got that should work for the rear, as soon as I went to walk out the door to do it earlier it started raining on me.