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Discussion Starter · #1 ·


Okay so it's a pleasant retro ride and has a few advantages over a completely stock FLH .
The front brake is complete crap . Complete and unadulterated crap . Even when it does work it's after 20 pulls straight to the grip and then and only then does it work . Release and commit to the same drill for each and every stop thereafter .

Look I've been in these things before and all it was , was parts replacement . this time something is different . Keep in mind I have 30 years of rice wrenching behind me as well as a smattering of H-D . I always questioned round O-ring in the caliper and have repeatedly asked about the sometimes called "friction ring/washer" in the groove at the bottom of the caliper . I have never had issues before but I suppose the one I own rather than a customer bike is ok .

Does this at all sound familiar to anyone ? It would be nice to have a real , operating , stopping , front brake ...

~kop
 

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There were a variety of issues with the banana caliper as new. One was with the retraction and extension. there was a factory upgrade kit tht helped with the issues. It consisted of a different piston , o-ring, and o-ring washer. There is a factory Service Sheet covering it. As you likley know the extent of the travel is merely the amount of "roll" in the o-ring. The kit helped with travel issues.
I'll look for the service info and scan it into here for all!
Robbie
 

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So many things can go wrong with brake systems. We don't change the fluids, unless they leak, and the maintenance on them, is shining the chrome. Now for the list of things to check. First look at your fluid, if it is not clear, dump it. All of it. Start out by disassembling the mc, and make sure the plunger is clean and the piston rubber is plyable and not stiff. Blow air through the two supply ports for the fluid, and run a small tip cleaner in them, then air and more cleaner and air. If you have a small brake hone, hit the bore a few wacks, just for shits and giggles. Now, go to the lines. Clean with brake cleaner, and blow out all the crap. Make sure you can blow both directions, and that the amount of air coming out, is equal(as equal as you can determine with your hand, no guage needed here). the rubber line, over the years, can breakdown and create a blockage. Sometimes it is just in one direction, but sometimes, both. It sounds like you have been in the caliper, but the same is needed. A kit, some cleaner(blow throuth the bleeder port, and bleeder, to make sure they too are clear. Fill the caliper, with the puck fully pushed in, fill the lines, and attach to the caliper. Hand bleed the mc, until you get pressure against your finger, and attach the line. Pump the handle, and watch the final bubbles of air come out the mc. Also, as mentioned above, the mc has to be matched to the caliper. Most banannas have 5/8ths mc's, unless they are duals, and they would need a 3/4ers. Hope this helps.
 

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My experience has been that the hole down the center of those old brake hoses closes up as the rubber swells with age, leading to some real weird brake behavior as the line is partially or fully blocked, sometimes or sometimes not etc. I have had them where brake would not work at or, or sometimes like you say, or even jam on completely.
Put a braided stainless brake hose on and it makes a world of difference.

For that matter, put a $40 eBay Tokico four pot caliper from a sportbike on there with a simple mounting adapter bracket made from flat plate and have a front brake that really works.

Sweet looking bike BTW.
 

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Discussion Starter · #7 · (Edited)
Okay , I have the FSM for the "banana" but not the update sheet . This isn't my first rodeo by a long shot but I don't mind asking because I've proved time and time again I'm either senile or ignorant . The M/C is an aftermarket V-Twin that with adapters works just fine with a jap caliper (had to verify with the only option I had) . I do have one question , wtf is the wave washer trapped by the staked on washer for ? Every other caliper piston I have ever had to work with was a square O-ring , I'm about to walk into the local bearing house and try to cross with an existing square O-ring unless I'm defeating some designed in function that the round O-ring performs .

Now cleaning the spilt beer and brake fluid from the keyboard ...

~kop

Hopper , tnx it's a long story for another time ~kop
 

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Discussion Starter · #10 ·
Okay , as of several minutes ago this is the result . Disassemble front system complete and clean . Reassemble and install . Four to five pumps will get you real brakes . You can visibly see the piston retract a bunch , as in way too much . The Tokiko six pot and an after market 320 mm rotor are looking real good right now .

~kop
 

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theres no info on when hoses should be replaced? according to clymer manual it should be replaced every 4 YEARS!!

better idea , stainless braid teflon pipes = done ONCE

the jap brakes sound good too ,hard to find a good looking front brake using existing mount tho.
 

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Discussion Starter · #13 ·
Okay who's the guru here ? I'm about pitch this abortion over the side for a way too pricy PM setup and again , it will stop but one it won't look right and two an inanimate pos will have beaten me . Neither is going to happen .

So now it's my understanding that the "wave washer" is there to hold the the piston at all but contact with the back of the pad and only advancing as the pads wear . This would be the same as the square O-rings I've used , maintained , serviced and replaced in rice bikes for 30 years . The square O-rings flex while still pretty much glued to the piston with just their tension to retract the piston until enough pad has worn away for the O-ring to slip a bit on the piston . My guess is that the banana parts accomplish the same thing with O-ring providing seal and the wave washer holding against full retract . I'm going to try one more time with an expansion ring behind the wave washer to expand it against the bore just enough to keep the piston from retracting near 0.080" after application .

Can you imagine not knowing which one of five to six pulls on the lever is going to produce lock up when the soccer mom from hell decides to dynamite the brakes for a yard sale ? Not only that when in non threatening conditions imagine the number of times that the lever is pulled to use the front brake and multiple by five or six .

Add to this that I'm coming from a daily driver that has brakes to die for and a totally ergonomic front and rear brake that are near reflexive rather than premeditated and you have a recipe for bent front forks .

Okay I'll admit I've been on the the KZ cop bike for most of the last 30 years but still this delayed , multi-pull , wtf ever brake just plain sux .

I'll report back with results and or the receipt for $500 + in PM brakes so you can laugh you arses off at the noob Milwaukee wrench ...

~kop
 

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Discussion Starter · #15 ·
Okay here's the story . The pos just wouldn't work at all , bled , re O-ring'd ,cleaned , bearings and rotor checked for run-out ad nausea ...

So there is this old skool wrench in the area that tells me to put all the clearance on the back of the piston by backing off the four caliper bolts about a turn and a half then pumping up the brake with a tooth pick stuffed in the pressure relief hole in the master cylinder . Then he says to tighten the the four caliper bolts with the lever still pulled to the grip . Then slowly release the pressure from the relief hole ...
I now have a brake fluid stain on the ceiling of the garage and a completely bled and working front brake . He called about 10 minutes after the DOT 3 geyser to warn me about the extent of the pressure under the toothpick . I really should have known anyway but about four tries and as many beers into it I get to tell on myself . So in short bleed the brakes then separate the caliper halves by a turn or three then have a third hand apply the brake while the caliper halves are tightened down .
I celebrated b taking the bike over HWY 410 for dinner and actually had to use my new found brake to avoid a deer on the way home . All is well after a fashion and the brake works as well as can be expected for a 70's disc .

~kop
 

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had the same problem. i would pump it up and then grab the puck with some channel locks then do it again untill it was out far enough to work properly. no stain no gain.
 

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Throw the Piece of 'S' at the Wall and Call On Performance Machine, it's a Big Bike that Demands Good Brakes, I had a 79 FLH as well, those OEM brakes are a thing of the past...
 

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Thanks kopcicle for a hint. 1/8 turn made my banana brake work like a dream. 1/4 turn was too much and it started heating.

I can even lock it on the road that I thought was impossible with that old banana brake.
 
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