Bringing FJ out of hibernation

[RichBaker]

Not happy with front brake perf. When first applied, nothing, squeeze a little more then semi-hard braking, not much in between (not so good with loose gravel on the road). Brakes are gripping well. Was able to lock wheel no problem on good pavement. Not sure if master needs rebuild, or maybe there's still air in system, but it sorta feels like something is sticking, then releasing.

Sounds like the way my front brakes worked when I tried the EBC kevlar pads.... On the dealers recommendation. I took them back and demanded they replace them with OEM pads... They did, no charge.  It was VERY obvious I was pissed!

[rktmanfj]

Yeah, like that. Except I managed to wrap the rod around at least 3 times. Was that a low speed discovery? Looks like a very effective parking brake.

It happened at about 20 mph.

Surprisingly, the brake was not dragging as pictured, and the bike was ridden over to my garage for repair.

Once the owner of the bike shop saw the pictures (which had been posted on my Facebook page without the shop's name), he quickly coughed up the cash for the repairs, which the owner (understandably) didn't want his shop to perform.

[zz28zz]

Not happy with front brake perf. When first applied, nothing, squeeze a little more then semi-hard braking, not much in between (not so good with loose gravel on the road). Brakes are gripping well. Was able to lock wheel no problem on good pavement. Not sure if master needs rebuild, or maybe there's still air in system, but it sorta feels like something is sticking, then releasing.

Sounds like the way my front brakes worked when I tried the EBC kevlar pads.... On the dealers recommendation. I took them back and demanded they replace them with OEM pads... They did, no charge.  It was VERY obvious I was pissed!

I just installed EBC HH sintered pads. From what I hear, everyone likes them. I'm hoping they will get better over time, but hasn't improved much in the first 60 miles. The lever pull is not consistent either. Sometimes lever is closer to grip than other times for the same rate of braking. I'll try bleeding again. If that doesn't work, may need to start looking for a 14mm master cyl.

[zz28zz]

Yeah, like that. Except I managed to wrap the rod around at least 3 times. Was that a low speed discovery? Looks like a very effective parking brake.

It happened at about 20 mph.

Surprisingly, the brake was not dragging as pictured, and the bike was ridden over to my garage for repair.

Once the owner of the bike shop saw the pictures (which had been posted on my Facebook page without the shop's name), he quickly coughed up the cash for the repairs, which the owner (understandably) didn't want his shop to perform.

Sounds like brake cam must have went over-center far enough to release the brakes.

[SlowOldGuy]

Did the front forks leak fork oil onto the brake calipers?  If so, then you'll need to rebuild the calipers as the oil makes the seals swell up and causes "notchy" braking like you're describing.

DavidR.

[zz28zz]

Did the front forks leak fork oil onto the brake calipers?  If so, then you'll need to rebuild the calipers as the oil makes the seals swell up and causes "notchy" braking like you're describing.

DavidR.

Fork oil did get on calipers (and everything else). I pulled them off and popped the pistons out to clean the buildup of gunk on the exposed part of the pistons. Did not replace seals. Just wiped clean with a rag and reinstalled the pistons. I thought I had got away without replacing the seals when they held pressure for a few days when I had brake lever ty-wraped for final bleeding.

Makes sense though. Thx for chiming in 
I'll start looking for a set of seals.
Any tips on replacing the seals? They're from a 87-88 FZR-1000 if that matters..Saw somewhere not to split the caliper halves cause they are difficult to get resealed.. Now that I think abt it, the seals between the caliper halfs may have got fork oil on them. Think they are OK?

[SlowOldGuy]

New seals for old style calipers will be ridiculously expensive.
Once they are contaminated, they are junk.
I might have some old seals that I could send you.  I replaced mine (that's how I found out how stupidly expensive they are) many years ago and still have the calipers somewhere.  Those seals should be in good shape.  I've upgraded to the '89 front end with monoblocs.

EDIT: Oops, guess I should read more closely.  Are the FZ calipers 4 piston or 2?

DavidR.

[zz28zz]

The calipers are off a 87-88 FZR-1000 and they are 4 piston.
I already ordered a set online. Thx for the offer though.
You're right, they weren't cheap at all. Close to $90 for both front calipers plus shipping.

I've had the pistons out already and cleaned them, but I've never replaced caliper seals on a motorcycle caliper.

Any tips on removing and installing the seals. Don't wanna mess them up!!

[SlowOldGuy]

It's realtively straight forward on replacement.  They are square cross section seals in a square groove.  Use a dental pick and gently pull them out without scratching the groove.  Each piston will have 2 seals, a dust seal and a larger piston seal.

How many seal "kits" did you buy?  If you only ordered 1 kit for each caliper, then you're only going to have enough seals to rebuild one caliper.  I did that when I rebuilt my '93 calipers.  Seems a "kit" only comes with seals to replace one side (or only 2 pistons).  I was all finished with a fork rebuild and major maintenance and only needed to finish the front calipers.  I only had half of the seals that I needed.  Had to wait another week for more seals to come in.

You might want to check and see if you ordered enough kits.

DavidR.

[zz28zz]

I ordered 4 kits. Each kits contains 2 press seals and 2 dust seals, so think I'm ok in that regard.

When I removed the pistons, it took 100 psi of air press to get them out. I got one out, cleaned it up and reinstalled it. Then secure it and 2 other pistons with ty-wraps, c-clamp, whatever and applied air press again to blow out the next one and so on.. I was surprised how much press it took to get them out.

In retrospect, the theory abt leaking fork oil swelling, or making them "notchy", seems spot on.

When you install the seals, do you install them wet or dry? I know the pistons will need to be wet when they go in.
Is it obvious which way the seals go in? I'm assuming the lip will need to face the fluid.


In regards to my email to Tarozzi, they responded with a link to their US distributor.
Looks like a good source for rearset parts. https://www.fastfromthepast.com (not affiliated with them at all)
I ordered the pin and circlips I was missing (plus a couple of extras). Prices are good, but shipping was a bit steep.

Dist emailed me with exact part descriptions and a suggestion I thought I pass along to any fellow bikers with rear sets; put a dab of silicone on the circlips to prevent them from jumping off!! 

[SlowOldGuy]

"Oil" the seals with brake fluid before installing.  The kits may come with some special seal lube, if not just use whatever kind of brake fluid you're going to use.  The seals are not directional, no lip, simply a square cross section friction seal.

Based on my contaminated brake experience and the description of your brake performance, I believe this step will cure your brake problems.

DavidR.

[racerrad8]

David & others...

Should I be looking for FZR kits for inventory?

Randy - RPM

[racerrad8]

Okay, after doing some research today the 87-88 FZR1000 calipers use the same rebuild kit as the 89-93 FJ1200.

I have those kits in stock and each kit has the seals for rebuilding one four (4) piston caliper.

Yamaha 89-93 FJ1200/87-88 FZR1000 Caliper Rebuild Kit

Heck, I have even added the caliper pistons to inventory as well and they will be here on Wednesday.

Yamaha 89-93 FJ1200/87-88 FZR1000 Caliper Piston

Randy - RPM

[zz28zz]

Okay, after doing some research today the 87-88 FZR1000 calipers use the same rebuild kit as the 89-93 FJ1200.

I have those kits in stock and each kit has the seals for rebuilding one four (4) piston caliper.

Yamaha 89-93 FJ1200/87-88 FZR1000 Caliper Rebuild Kit

Heck, I have even added the caliper pistons to inventory as well and they will be here on Wednesday.

Yamaha 89-93 FJ1200/87-88 FZR1000 Caliper Piston

Randy - RPM

My research indicated the same thing. I found the seal kits on your site and started the order process. When I changed my quanity to 2, it turned red and indicated you only had 1 kit in stock.
I just tried it again and it let me change quanity to 2.
Did you add a kit to stock in the last couple of days? I would have preferred to buy from you.

[racerrad8]

My research indicated the same thing. I found the seal kits on your site and started the order process. When I changed my quanity to 2, it turned red and indicated you only had 1 kit in stock.
I just tried it again and it let me change quanity to 2.
Did you add a kit to stock in the last couple of days? I would have preferred to buy from you.

Yes, my stock order came in yesterday. If at anytime you come across something like that send me an email. I can get things quick than my weekly stock order if required on many parts.

Randy - RPM