Brake lever travel.....what else?

[ctandc]

The bike is my 91 Katana 600.

The front brakes work great. However I'm not satisfied with the 'lever feel'. In other words I was sitting on a new 06 Kat not too long ago and noticed how the lever was solid after very little travel. My lever takes a good bit more 'pull' before the brakes engage.

Pumping the lever up does NOT improve the travel.

What's been done to the front brake system:

-Stock calipers cleaned up and rebuilt
-Installed speedbleeders
- EBC HH pads
- HEL braided 2 line system (eliminating the splitter)
- Master cylinder from a low-mile 2006 Katana.


I have bled / flushed it repeatedly. I have tied the lever in overnight, once with a the master cylinder cap, once with it on. No difference.

I did crack the lines loose at the master cylinder and try to bleed the master cylinder.

I even tried a Mityvac on the system last night:

Pulled vacuum on the pump, hooked the line up, then cracked the speedbleeder open. There seemed to be some TINY TINY air bubbles that came out at first, but then just fluid.

I have tapped, banged, etc on lines and calipers in case there was air trapped anywhere...same result.

What's next?

Replace the master cylinder?

And to make sure people understand what I'm saying...

The lever isn't "mushy"...it just goes back without much resistance at all for a good bit, THEN it bites with good feel and solid brakes.

[catfish]

it sounds like you have all your bases covered. i might swap out the master cylinder with the old one, and check the action, before purchasing a third master cylinder?

[Black_peter]

Keep at it. Try bleeding up. Not sure how you're using the minivac. On the caliper or the MC..
You can bleed up using a syringe to force fluid up from the caliper to the MC..

[HS2020]

Ct do I have your number If so I should be able to call you tonight. Fashers did that at first when I did her brakes. I had to go back and bleed the crap out of them again. When you bled the system did you start with the side farthest from the M/C Then work your way back. That is how it should be done. You may want to rebuild the M/C which is very easy to do. $15 for parts and about 15 minutes of work. The M/C plunger and spring could just be wore out.

[ctandc]

Keep at it. Try bleeding up. Not sure how you're using the minivac. On the caliper or the MC..
You can bleed up using a syringe to force fluid up from the caliper to the MC..

I'm going by the parts store on the way home to get ANOTHER bottle of brake fluid to try again.

Vaccum pump was used at the caliper(s).

Started at the inboard bleeder, LH caliper. Attached hose (speedbleeder closed) build up vacuum (and it held, so no leaks at the hose connected to the Speedbleeder). Opened the Speedbleeder a bit. Fluid and some TINY air bubbles started coming out. Kept refilling master cylinder and repeating until no bubbles were visible.

Repeated process on other LH caliper bleeder, then repeated process on both bleeders on the RH caliper.

I'm going to try the other master cylinder I have tonight and bleed it again to see if there is a difference.

How would I use the vacuum pump at the master cylinder?

[Black_peter]

How would I use the vacuum pump at the master cylinder?

Well I guess you can't. But some have attachments for pulling vacuum on the MC and drawing fluid up from the calipers. That way you hook it up once (on a car say) and pump at all four calipers.

[steves]

Maybe tighten the line a little bit more at all the bolts? Just a smidge....

[ctandc]

Maybe tighten the line a little bit more at all the bolts? Just a smidge....

I'll check 'em again.

[steves]

I'll check 'em again.

When I did one of the bikes I did last year... I pumped about 2 quarts through with no luck... then I just gave the lines a little extra "oomph" and I was done.

[OBrian-DK]

When bleeding the brakes a lot in a try to get all the bubbles out, is there something wrong about reusing the fresh brakefluid in the process, or is it just throw away, and buy another bottle???

[catfish]

you want fresh fluid in the lines, always, as a rule

however he HAS replaced all the lines, the master cylinder, and rebuilt the calipers AND flushed a few bottles through...

[arsenic]

I agree, the only possibility left is front master cylinder cup/piston set.

[elkat]

Are your front wheel bearings good? I went through all that, and the bearings were loose enough to push the caliper pistons back in and give it a mushy feel. Just a thought.

[Teh_K]

Actually, the brakes on both my 2000 Kat750 and 1999 Kat600 developed the exact same symptoms when I switched to your setup (rebuilt calipers, HEL 2-line kits, new pads, Speedbleeders). I did a ton of bleeding, and I still can't get the lever to engage without pulling it in a ways (more than the original setup)... I just assumed it was part of switching to SS lines, but then my friend did on his sv650 and his were SUPER solid, so now I'm like wtf...

[HS2020]

Well i can tell you the lines have nothing to do with it. The travel of the handle has to do with bleeding of the lines. Fashers did the same thing. We had to bleed and bleed to get it to be very strong feel. I had to do the same thing on my bike. If you pump the handle with the cap off of it all you are going to do is put air in the lines. You have to bleed the M/C then put the fluid in close the cap and bleed the calipers after that. If you do not do it that way you will have air in the lines. I will be off work tomorrow at 5pm CST. You can get my number from my site. I will talk to the ones that need help.

Those with speed bleeders remove them and see if that changes anything.