Brake Lever Firmness on '80 GS1000E/ST?

[Nessism]

The front brake lever on my 850 is extremely firm and only pulls back a short distance compared to my 1000ST brake which pulls back about twice as far before it firms up. The 1980 GS1000E/ST master cylinder uses an O-ring instead of the more common cup seal as used on most other models so I'm wondering if this is a characteristic of this particular master? My master has fresh seals, as do my calipers, plus teflon/stainless lines, but the lever still pulls back more that I'd like. The braking power seems fine, and once the lever travels back about 1/3 of the way back is gets nice and firm. Problem is that it's hard to ride with two fingers on the lever since the inside fingers get pinched against the grip when using the brake. The brakes have been bleed well so I don't think there is air in the system.

Any 1980 GS1000E/ST owners out there that can share their experiences?

[hikermikem]

Hi Ed,

My 750 had a similar feel until I pulled the calipers off the rotors & pulled the lever back a little to close up the pads a bit - then I gently pryed open the pads & pushed them over the rotors. Took care of all the sponge & the firmness returned...

[OldVet66]

Sorry, misread your comparison. 1/4" before it firms up should be about right, 1/3 travel seems excessive. When I rebuilt mine and replaced with SS lines, I switched to DOT5. It has all the breaking power you would want with two fingers, and it's an older system.

[waterman]

How many miles on the 850 compared to the 1000. I ran into a similar situation with my brother's 1000g 60K bike compared to the brakes on my 10 K miles 650. I figured his rotors were worn and thus the difference in lever travel. Since it was his bike, I didn't try to remedy situation. I didn't want him to do stoppies the first time he took it out. I did replace his DOT 3 with DOT 4.

If I get to tune his bike this winter, I may suggest a brake upgrade, I have been working on the kaw twinpot, cbr900r rotor mod.

How much have you driven 1000? Are these new pads? May need more time to bed in?

[Nessism]

How many miles on the 850 compared to the 1000. I ran into a similar situation with my brother's 1000g 60K bike compared to the brakes on my 10 K miles 650. I figured his rotors were worn and thus the difference in lever travel. Since it was his bike, I didn't try to remedy situation. I didn't want him to do stoppies the first time he took it out. I did replace his DOT 3 with DOT 4.

If I get to tune his bike this winter, I may suggest a brake upgrade, I have been working on the kaw twinpot, cbr900r rotor mod.

How much have you driven 1000? Are these new pads? May need more time to bed in?

Pads are new and the rotors have some wear but not too much. Guess it needs more time but not sure.

Been talking to Salty Dan about some new brakes but this bike is more of a restoration than anything else so not sure I want swap the parts just yet.

[hikermikem]

Hi Ed,

My 750 had a similar feel until I pulled the calipers off the rotors & pulled the lever back a little to close up the pads a bit - then I gently pryed open the pads & pushed them over the rotors. Took care of all the sponge & the firmness returned...

Let me supplement my response with some additional info..

The front MC & both calipers were freshly rebuilt & new SS lines had been installed - DOT 4 fluid & bled (and bled & bled & bled...).

For some reason the caliper pistons would pull completely back into the calipers, thus the "extra" lever travel before the pads would hit the rotors. Perhaps that's your issue as well.

[salty_monk]

Ed,

Pull the lever back as far as you can (will likely touch the bar) cable tie it in that spot & leave it for a day or two.... (put something over your grip so you don't permanently distort the rubber.

Report back if it makes any difference. Worked for me on my Skunk. It's a trick I learnt on old classic cars a few years back.

Worse case it'll cost you nothing & make no difference

Dan

[chef1366]

Round M/C?
It's normal

[salty_monk]

Nope... it's the 80 square one. The opaque bit snaps onto the main unit with an O ring at the bottom.

I had the same one on my G & it worked ok. Not super firm but better than what Ed has....

Try my cable tie lever trick first.. if that doesn't work we'll try something else, you're not riding it right now so the couple of days won't matter I assume.

[Nessism]

Nope... it's the 80 square one. The opaque bit snaps onto the main unit with an O ring at the bottom.

I had the same one on my G & it worked ok. Not super firm but better than what Ed has....

Try my cable tie lever trick first.. if that doesn't work we'll try something else, you're not riding it right now so the couple of days won't matter I assume.

Yea, it rectangular but the part number for the piston is different than the G model for some reason. Oh, and I've already tried the pull the lever back trick.

I'm starting to think the issue is related to the calipers now. The sliding pins and caliper hanger are showing some wear so maybe they are hanging up a little since the pads aren't bed in yet. Need to get some more miles on this thing...hopefully next week.

[Steve]

I just went through this with "Freebie". The lever had very little feel to it, even after going through most of a 32 oz. bottle of fluid in the bleeding process. I tried pumping fluid up from the calipers with no improvement. What has finally added some feel to the lever has been hikermikem's suggestion:

My 750 had a similar feel until I pulled the calipers off the rotors & pulled the lever back a little to close up the pads a bit - then I gently pryed open the pads & pushed them over the rotors. Took care of all the sponge & the firmness returned...

I also have new pads in there and did not think of that being a problem until I saw waterman's reminder that new pads need to bed in:

Are these new pads? May need more time to bed in?

We will just have to put some miles on it and see if the situation improves. Problem is that it's 30-some degrees out there, we have to dodge the icy patches on a test ride and #1 son is wanting to take it with him on Sunday.

.

[srsupertrap]

May try this . . . barely crack the bleeder screw and squeeze the brake lever real hard to compress a small amount of brake fluid out the bleeder hose. Close that bleeder screw each time before the brake lever contacts the grip. Repeat till your sure you have purged the entire volume of the brake system. Repeat on other side. I have a 80 square M/C.