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Discussion Starter · #1 ·
Hi all,

My 70 CL450 has been converted to a front disc brake sometime in it's life. I was told it's off a CB from a couple years newer machine. The problem is that the brake is really not that good. The brake feel is weak and the lever pulls almost to the handle bar. I've bled it and still not good. I'm wondering how good the disc brake was back then. I was thinking about finding a newer master cylinder and try that. The pads are new and the caliper moves freely. Any suggestions?
Also, I thought about putting a drum brake back on but I have heard they were terrible too.
 

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SS brake lines will help, you can also rebuild your current MC or just replace it with an aftermarket one(it will cost about the same either way). New pads are probably not a bad idea. These brakes were never great but you def have something wrong if the lever is bottoming out after proper bleeding.
 

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I wouldn't say the brakes aren't great - mine stops as hard as any bike I've had. That's after a full cleaning of the slave cylinder, with new piston, seal and pads, new stainless-wrapped line, and a careful bleed, including the banjo fitting, which can be an issue. I didn't need to touch the master cylinder. The slave piston and cylinder both had a build-up of sticky stuff (old fluid), which made it feel weak.
 

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I just meant in comparison to modern bikes.
 

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I suppose it does feel weaker than bikes made 40 years later, there's a big difference in technology and commonly installed discs, more often dual discs of course, today, but I can tell you that the first front disc on the CB450 was the exact same as the early CB750 and the bike weighed about 75 lbs less... in good operational condition, that single disc would brake hard enough to cause a front end washout if you weren't careful back then. And as far as drum brakes back then are concerned, the double-leading shoe drum on the front of my CL450 stops really well for something from that era too, and back then road racers weren't always using discs because the technology was still developing and not a simple retro-fit until later on, so many road racers used double-sided double-leading shoe front brakes (or 4 leading shoe, as they were often referred to) which were as good as it got for the era. We're just spoiled today because so much improvement has happened over the 40+ years since what Honda used was considered more than safe enough for the performance level then.
 

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Discussion Starter · #6 ·
Where can I find the SS lines? And where can I get a rebuild kit for the master cylinder? If you guys think the disc is a good choice, I will stay with it and get it working right. Thanks for the help.

Acientdad, Did this bike have DLS??
 

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I get most of that stuff on ebay but there are plenty of other options if you search around the internet, I just happen to like ebay.
 

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All Hondas from CB/CL160 and up had DLS front brakes back then (exceptions were, IIRC, the same sizes in the CA model - Dreams) so yes, the CL450 always had it from the beginning as far as I know. One thing I can tell you that might add up better for you at this point in history, since pretty much all except NOS shoes are gone (and they probably are too, as old as that would be would make even them less than trustworthy) is that having an OEM disc on a vintage bike today is probably better for one reason - the shoes sold today often suck. I bought a set of Vesrah shoes (great gaskets, used to be decent shoes) for the rear of my 450 and they were junk, worst shoes I've ever had. Fit poorly from the beginning, and the next set I bought (EBC) are better but still not quite right... more miles will probably bed these in okay but right now they're at about 40% of what they should be because they just aren't properly arc-ground to fit the drum size they're intended for. Pads, on the other hand, should be a no-brainer - since they're made to fit a flat surface, and as long as they're a decent brand and of decent materials, you should get good stopping power combined with either a good replacement master cylinder, or a good rebuild on the existing master, along with a good rebuild on the caliper and braided lines
 

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Discussion Starter · #9 ·
Arcing them to fit is pretty simple. Get some adhesive backed sand paper. Cut it to the width of the drum and stick it to the drum surface. With the shoes on the backing plate, insert into the drum and rotate back and forth using the brake arm to apply pressure. Makes a perfect arc.
 

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I just meant in comparison to modern bikes.
I'm comparing to a 2005 Suzuki S50 and my 1998 Honda Valkyrie, but then, I've got a fairly strong grip (and the Valk weighs 910#). Brakes are good enough to stop the bike and not the rider. ;D
 

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Go to vintagebrake.com and take a look. Lots of good info.
 

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I brought a complete front caliper assembly with pads from 4into1.com, best price I could find on every piece below the brake pipe. (Incredibly fast shipping too because I’m in their time zone!)

I believe my ‘76 CB500T has the same front assembly, if not then it will be very similar in design to yours, maybe just some sizing/dimension variations.

My first take when I acquired the bike was that the front brake felt a little spongy. And, yes, I can almost pull the lever all the way to the handgrip. But after a few hundred miles, I’ve learned to accept this as a 40-year difference in technology evolution.

I’ve done work on these brakes and it has been inspected by a professional mechanic who specializes in ‘70s superbikes from Japan. He had no flags and insisted that brake feel is “vintage” and “part of the bike’s character.”

So the front brake works well and I’m always stopping in time and in control. The difference between this and my previous two ‘modern’ bikes may just be a matter of feel and how far the lever will travel. It feels different to the uninitiated and I think it’s a matter of design, having a larger MC, a single caliper piston, etc.

It will boost your confidence to have a professional look at it at least once. Since I have, I’m now of the mindset: if it feels soft, no worries as long as you also feel like you’re stopping in time.
 

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Discussion Starter · #13 ·
I was a auto mechanic for over 20 years and worked on many disc brakes. These are very simple and in a car this feel wouldn't pass. It doesn't get any better if you pull the lever multiple times so no air in the system. Maybe like you say Dave, it is what it is. It's just hard to get used to.
 

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I strongly recommend an upgraded, aftermarket m/c I got mine, built in switch kind from EBAY and it stops my bike better than stock, for sure! I also upgraded to custom stainless steel lines.
Beyond a doubt, it works better than stock but I still don't expect my ride to stop on a dime, which I think makes me a safer rider when I keep that in mind. You have to perhaps reluctantly accept that you can improve it but ultimately "it is what it is" and you cannot compare it to modern bike brakes, which isn't fair anyways.

good luck
 
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