Mushy front brake, has antidive

[Anonymous]

I am the proud new owner of a 1983 Katana 750, all original and practically unblemished, well not counting the Old Wolf Header. The old Kat has just over 9,000 miles on the clock and had been stored in a dry basement for about a year before I got it, (for a very good price). One of those rare finds, not even any fading on the original paint, seat cover or speedo face.

When I got the bike the back brake had "0" pressure, a quick bleed braught it to 100% (as far as I know).

The front brake was not so easy. Squishy, very Squishy! I have bled it left to right, right to left, by pumping, by vacuume, by gravity etc. The pads look good, the sliders and pistons look good and move freely, the antidive seems to work, and yes I bled the antidive too using the old rule of thumb - bleed the furthest furst.

Any one else had this problem? I have a 1975 gt 550 under a tree that hasen't moved in years, front brake is about 1/4 " from lock up and my Kat goes to nearlyl the bar. 8O

Pat

[mcycle-nut]

Replace the brake hoses. I could pull the lever to the bars (stopping well before this) on my '78 GS750 with the stock hoses, so I replaced them with braided steel lines. Now I can only pull the lever about halfway to the bars, again braking pressure point is well before this. 8)

[Anonymous]

You must have air somewhere in that system and as long as you have that worthless anti-dive hooked up it will be a real chore getting it bled right. The factory manual has the correct bleeding procedure. I have seen a couple Suzuki's with the anti-dive that had a good feeling front brake but most do not, even new from the factory. The anti-dive really does nothing. The first thing I do is disconnect it and put in heavier fork springs. Thicker oil helps too. That way I get less dive and decent brake feel.
Axel

[Anonymous]

I took my antidive servo's off tonight and felt the plunger as I applied brake. The brake feels soggy before the plunger even moves. I don't discount the effects of the antidive system but I prefer to make the bike work properly stock, I can't believe any machine would not be recalled if it's brake felt like that in its' own day. When I get it to work as it would stock, my modifications will be improvenents, not masks. If I unhook antidive, replace springs and lines only to find out the master cylinder is bad I will be ready to sell the bike.

I gave it another go tonight, I got the bright idea to put my finger in the master resevoir and cover the fluid intake port in the bottom and pump the lever. Many bubbles came out of the pin size hole, er, compensating port? I belched and burped my heart out on those holes, covering one then the other, Big smile on my face, I'm winning, I'm winning! Until I realized that the volume of air that had come through had exceded the volume of fluid in the resivoir by a factor of about 10, it occured to me I was probibly sucking air past the master cylinder plunger which is probibly only designed to seal in one direction. Next step, block things off until it improves.

What I am looking for is the "eurika" that puts it right, I want to figure out what is wrong with my bike. Then if cash and motivation permits I will modify to improve.

Pat

[Clone]

soggy brakes

My bike is an 83 GS750E with the antidive intact, originally my brakes were a little soft. Bleeding everything improved them for a bit, then they were soft again. I eventually took the master apart to find the problem. The worn seals worked on compression but seemed to allow air in on release. Putting a brake kit in and cleaning the crud out of the master fixed the problem. I have ridden an 83 without the antidive units and just a machined plate over the forks. My bike noses down way less. The antidive units serve a purpose. Check all the seals, throw in a kit, and if necessary replace the brake lines. BEFORE, you start taking things off and throwing them in the garage.
My 2 cents.

[Anonymous]

Re: soggy brakes

My bike is an 83 GS750E with the antidive intact, originally my brakes were a little soft. Bleeding everything improved them for a bit, then they were soft again. I eventually took the master apart to find the problem. The worn seals worked on compression but seemed to allow air in on release. Putting a brake kit in and cleaning the crud out of the master fixed the problem. I have ridden an 83 without the antidive units and just a machined plate over the forks. My bike noses down way less. The antidive units serve a purpose. Check all the seals, throw in a kit, and if necessary replace the brake lines. BEFORE, you start taking things off and throwing them in the garage.
My 2 cents.

I believe this is also occuring with my bike. I drove another 83 Kat when it was about a year old, I know people say they are noted for not having a great feeling brake, but I remember so much about the impressions that 1st drive on a sport bike gave me, if the brake had felt like mine I would have remembered it as a major "Yuck" and not had such a fond recall of the afternoon my friend loaned me the cool bike. ( I was just a kid of 26).

When I put my finger over the brake intake port it sucked air with no reservation. I don't mean to dis the helpful advise that I absolutely asked for. It's just that the bike is so amazingly clean and in original paint that I would like to maintain that theme as far as I can. A new master cylinder kit will be ordered asap, if that dosen't make a dif, safety will prevail and the short lines will go. I got legal tonight and went for the first real drive, those brakes are real bad.

Thanks for responding
Pat