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jb-

yeah, i was gonna pick your brain in NH. Baker didn't want the new variable so he skipped using the shoes at VIR, but i used 'em.

OK, so we had four practice sessions on Friday and i kept taking freeplay out of the line all day and then just kinda figured they were bedded in. keep in mind i've never had the race compound stuff so i have no point of reference. i couldn't feel that they were tons better than the street shoes but i did feel a bit more confident, they never faded and were very predictible, but i didn't notice any real change through the day. and then the other factor is that VIR is a fast track. lots of braking for T1 and kinda hard for T10, but otherwise pretty sedate braking zones as compared to NHMS T3/T6/T12.

so then i head out for saturday/raceday practice and take it pretty easy for the first/cold/more traffic session so i didn't really notice anything new or different. then in the second session i started trying to make some fast laps and do some passing at pace. aron comes flying by me on his fast-duc under the bridge into T7 so i try to keep pace with him, we make it onto the straight and get the sign for the last lap of practice on our way into T1. well, once i get to the braking zone i grab the front at marker 5 (which is the totally safe/wuss/don't cook it on the last lap in practice marker) and nothing is there, i stay on the brakes and stuff down the gears and still have have too much to finish the corner, i start to lean in, feel that it's not gonna work and take the generous runoff only to gently slip and fall on some dewy grass near the tire wall running at about 5mph.

i get it back to the pits and joeC asks what's the matter and why is there grass on my bike. i tell him i don't think i had much brake in T1 and he grabs my lever and it comes all the way to the bar with no effort and tells me how i actually had no brake. so we take the slack out of the line while rosko fixed my alignment and i go back out for my first race (the big bump into V3 which is just practice anyway) and the brake effin' rocks. i was still too much of a wuss to brake any deeper than marker 5 at T1, but was almost stopped every time through. and everywhere else, especially T4/T10 i was just killing folks on the brakes.

so obviously they took 6 sessions at VIR with my braking style to bed in. i had the one moment at the end of a six mile long straight, but after that they were spot on and i know i didn't use them for as much as they had to offer, but the difference was pretty huge. and there is no way i'd go back to a street shoe, it just kinda seems silly after how these felt. so after four years i'm kinda startin' to figure things out a little. thanks again johnny, i can't wait 'till i'm used to the improvement.

-tt
 

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I did opt out on the new shoes like tt saysI didn't want too many new things to deal with. Summit could be a different story.
 

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Discussion Starter #4
TT,
Hmmm.... did you do the "off the forks" axle tightening routine when you installed the wheel?
Sounds like you were working on one shoe maybe. Rosko adjusted the linkage then it worked good?

It always a tough call for me to set these up off a bike in the shop with just an axle shoved through them. Pretty easy to get contact in one spot, then that wears down and puts a lot of slack in the cable and throws off the linkage adjustment. Once both shoes are bedded in it becomes a lot more consistant and the linkage adjustment stays good a whole lot longer.

That linkage adustment is hugely important, just a couple of turns can make a big difference. Sounds like with some more laps and a final tweak of the linkage you could expect even more brake.

A good indicator is the lever....it should come to a pretty solid stop with very little sponge. If there is sponge, check the cable first, make sure it's seating properly and not "straightening out" at the ends when you pull the lever hard. You want the cable to enter the perch and the brake nice and straight with no pressure on the lever. Then if that's all cool, you check the linkage adjustment.

Usually the final tweaks are good for another 10% more braking power. If you have any reason to pull the wheel during the season, check the shoes for contact area. You want it to appear as if as much of the shoe is contacting the drum as possible.

If I make to VC I'll check it over.
Thanks for the feedback.
JohnnyB
 

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johnny-

i did the initial setup with the hub off the bike like we talked about. then through the VIR weekend, the only adjustments made were to the cable. it is still kinda spongy so i think i'll look at the linkage a bit closer again. i'll pull the wheel just to get a good eyeball anyway.

thanks for the help-
tt
 

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Discussion Starter #6
I just looked through a few manuals for older Hondas that used DLS brakes...for some strange reason I have never found a service manual that describes how to adjust DLS brakes. Or even how to replace brake shoes for that matter.

I've been looking for a concise set of instructions I could save and send to people rather than trying to type one up. It's a hard process to describe. Bottom line...you want both shoes contacting the drum at the same time (actually I prefer a slight lead on the rear shoe to compensate for linkage flex).

When done properly, if you push on the brake arm with your fingers as hard as you can it will come to an abrupt and solid stop, no more movement at all by hand. If you move the brake till a shoe makes contact and you can still grab the secondary short arm and move it toward the other arm then the link needs to be shortened.

It's harder working from the other direction...so I usually lengthen the link from the get go to make sure I know where I'm starting from.

If you think you have everything right, linkage and cable...but you still feel too much sponge...then watch the front hub as you apply the brake....if it moves side to side, or the backing plate moves away from or toward the hub...then something is misaligned. Axle bent a tad, spacers not turned square on the ends, or the axle not tightened properly prior to installation in the forks. The hub WILL move a bit rotationally...that's normal. (a tiny bit of side to side movement....like 1mm or less seems unavoidable in my experience, due to flex in the drum, axle, forks etc.)

The only sponge you should feel in the lever is cable flex, if you feel sponge, first thing you do is apply the brake medium hard....now watch the BRAKE ARM while you apply more brake.....is the brake arm moving....if so then the sponge is in the brake. If the brake arm is not moving....then the sponge is in the cable. The cable should fit nice and secure into adjustment nuts nice and straight....no slideways slop or the brake lever will move to take up this slop and feel spongy. The cable is very important...I've seen lots of brake cables sitting in oversize adjustment nuts (or undersize cable ferrels) at an angle...you can watch them straighten out when the lever is pulled.

As your brake/hub gets more precise it will show up problems elsewhere. Eventually if you get it right you will become addicted to excellent brakes, with excellent power and feel.
JohnnyB
 

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Timely reading material, right there. ^^

I've been trying to diagnose my brake failure from last year. When I pulled the brake apart this week (Vesrah shoes) the first shoe has no wear on the heel, but the second shoe has no wear on the toe. (Or is it the other way around?) Both cams seem to be in exact alignment as far as actuation goes. JB, you seem to suggest having a little extra cam in the second shoe. I want to shoot a little video or a few photos and send them to you for input.

I DID get a full size lever to replace that shorty P.O.S. I had on there, and I was planning on cleaning/scuffing the drum in case I glazed the thing. I was really hoping to have the 101 track day to get the thing dialed in before Vintage Celebration.
 

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Another thing to remember is that with race compound brakes you need to keep some heat in them to work. At VIR we're only braking in 4 places on a fast track. If things are adjusted properly and they're not working, trying covering vent holes in the drum.
 

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Discussion Starter #10
George....that sounds like a typical case of shoes that have not be arc'd to fit the drum. The shoes form a very minor OVAL inside the round drum and only the points of the oval touch the drum. Without disassembling for arc'ing you can at least sand down the high areas and not touch the low areas. Not very precise but it will help.

On properly arc'd shoes the contact will start towards the pivot and progress around the shoe to the cam side very quickly...almost instantly ideally.

As Unga says, race shoes like some heat. The compound I'm installing on these shoes is not as bad as some compounds in that regard, but they still need some heat. Overall race shoes just work at a higher temp range...need more heat to work well....will tolerate more heat and keep working well. This compound while not extremely aggressive is almost immune to fade.
JohnnyB
 

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Hmmm... I thought you said you'd arc'd those with the hub. I think it's really strange wear, but extra eyes would be good. I've got to get those photos.

I just can't get my head around the dynamic geometry somehow. I wish I had a streeter I could use for experimenting.
 

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Discussion Starter #12
George, how much have you used them, and how hard?

Next question would be how you installed the wheel. With forks using and axle clamp you have to tighten the axle with the brake applied by hand BEFORE it is installed into the forks.
On bikes with "through the forks" axle you install the wheel first, then tighten the axle while applying the brakes firmly.

This process aligns the shoes and hub, and as you tighten the axle it locks it in place. If you don't do it this way it axle will torque the hub and shoes out of alignment.

I arc all the shoes/brakes that I send out, and do the initial linkage adjustment with an axle slide through the hub. But...It's not on a bike, problems with an axle, or fork alignment etc. can throw the whole thing off.

In a less than ideal situation you'd have to adjust the shoes by sanding. Send some pics if you get a chance. To my email if you still have it.

Also...those short levers....way too little force for a race brake. You gotta have some good leverage at the lever. How many races do you have on it? Vesrah are going to take some time to bed in...they are designed to last a long time...not necessary stop real well. Race shoes sacrafice themselves for braking power, so they bed in quicker.

Check your axle for a bend too, check that spacers are flat and square. What works on the bench doesn't always work on a bike, depends on how "right" the bike is.
JohnnyB
 

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johnny-

so your hub and shoes are spot on. the contact area is huge, from front to back on both shoes with just a little difference at the corners of the trailing edges. i did find another broken spring and a little gouge (maybe the shrapnel or hanging spring) on the taper of the leading edge of the lower shoe. it seemed it would be below the contact surface, but i smoothed it out anyway. and as to my spongieness, i can see a litte expansion in the cable braid, at the lever, when at rest, so it's obvious now that i need a new cable. who's cables do you like?

thanks again.
-tt
 

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Discussion Starter #14
TT,
Motion Pro makes a good cable if they have them for that brake...order one to match the hub, so 305 for 305 etc. Although I don't think there is any cable difference in the 450. As heavy duty as you can get.

Another broken spring? That's weird...they move so very little on a brake like yours. I'm having trouble finding good springs, most of them are too rusty. Keep your eyes open for NOS stuff. At some time I might have to look into having some made. Or finding something later model still made that will work.

Typically there will always be a tad of dead contact space towards the pivot until you really get some laps on them.
JohnnyB
 

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The wheel installation is a component I didn't have any control over since the shop reworked my axle at the last minute. There's a very good chance that was a factor. I'll proceed as advised on re-installation. I noticed there is a ton of play in the brake / hub interface.

The pads hardly have any break-in. I had 2 practices and two laps when I went down. They've got lots more breaking in to do. I got some photos, finally. They're up here: http://smg.photobucket.com/albums/v356/GeorgeZboy/Cycletrips/
 

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Discussion Starter #16
George,
Hmmm....what kind of shop did the work? Was it a vintage shop? If not they probably have no idea how to install a drum brake. What did they do to the axle....the axle is a major factor as it is what holds the alignment between the hub and brake plate. Looks like the whole brake plate is offset in one direction in the hub. Very unusual to see all the braking on ONE side of the plate at a pivot/cam area. Usually you'd see wear at both cams, or wear at both pivots if arc is wrong.

Do you think the shop removed the shoes for any reason? If so they might have put then in backwards (top on bottom, bottom on top).

Things like spacers are very important...if the ends of the spacers are not lathe turned square (perpendicular to the axis of the axle) when you tighten the axle it tries to cock the brake/axle sideways. Spacers cut with a hack saw etc will not be square enough.

When I build a race brake the tolerances are much closer than on a street brake....this requires that the installation be much more precise because now small errors will have a large effect on how the brake works.

I'm guessing when you apply the brake you see that "play" as the brake plate trying to move separately from the hub.... this is because the two are not aligned. The process of applying the brake BEFORE tightening the axle holds the plate and the hub in alignment....then when the axle is tightend it locks it in place....so you don't have the movement....cause it's already where it wants to be....if you take my meaning.

If this is not done then every time you pull the brake lever it's trying to bend the axle and bring everything in alignment...which it can't do of course. Your lever has got to be all kinds of spongy.

Typically I label the shoes top and bottom. Make sure that's right first. Although I know there have been sets I didn't label. I actually label them for myself as I have a special plate I use on the lathe for turning the shoes and then transfer them to the customers plate.

And by top and bottom shoe I mean the top shoe is the one that is toward the top of the bike, and vice versa....it doesn't mean what is facing up and what is facing down as you look at the plate on a bench.

That big movement between the plate and the hub is almost without question the problem, and that movement is indicative of a mis-alignment during installation. Believe it or not...despite the fact that these are old, primitive bikes, things like the brake have to be quite precise to work properly in a race scenario. There are very few shops outside a vintage race bike shop that will have any idea how to set it up properly. You'd do a better job at your house with some care and instruction.
JohnnyB
 

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hey george when the heck did you re-paint my bike? Remember, I want it back if you ever decide to sell . . . .
 

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Evil - It's a Tannermatic tank and fender - no repainting.:D

It was The Motorcycle Shop that did the work, so I expect the work is at least competent. They had to cut spacers to mate the 550 forks, 750 triple, and 77 hub. I'll check square on those first and check the axle for straight. They had no reason to touch the pads, but I'll check those too.

I don't recall loosening the axle from the wheel last year, but I know I loosened the axle from forks (to drill the nuts) after the shop had the bike. It's likely the "squeeze, tighten" protocol was not followed somewhere along the line - probably by me in my ignorance. I'll have to see how much motion I get in the kit when I get it all reinstalled - hopefully Sunday.

Thanks for the feedback.
 

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Discussion Starter #19
If you are using 550 forks...that's the same as I use. The process is kind of a pain in the ass.

With the wheel off the bike you take something like a quick clamp and put one end on the brake arm, the other on the cable stay and tighten the clamp to imitate the cable applying pressure. Not so much you break something...but considerable pressure. While this clamp is in place you put the axle through, along with any spacers needed and tighten the axle.

The 550 forks are VERY particular about spacers...the way the axle is setup the axle nut has to fit perfectly aligned in the clamp, if you have to tweak the forks even a tiny bit to get the axle to seat in the clamps then it's not right.

When you slide the wheel under the forks and lower the bike...the axle should fit right up into the clamps with NO drama. The shouldered axle nut should slip right into the clamp.

After the wheel is installed...you should never screw with the axle with the wheel in the bike...unlike a lot of bikes, the wheel/axle setup on a 550 is a whole separate package from the fork legs.
JohnnyB
 

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johnny's speaking a lot of truth on the (drum) brakes. i'll just add a couple of my thoughts. first, cables aren't usually the sponge culprit...the casing/housing is (along with the ferells etc. as johnny wrote) crappy casing compresses due to a sloppy wind. teflon lining, which is popular, adds to this although i use it on my racer. and i am a firm believer in arcing the shoes on the brake plate which compensates for many of the manufacturing flaws present in most bikes...especially spanish tacos from the sixties. when i did it last, i made a gismo which loaded out the shoes a bit, turned them to the i.d. of my drum, and had super brakes first time out. they wore/ were contacting from leading to trailing edge on both shoes. re-read jb.s hints too.
-parks
 
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