What a hoot!! (first ride) Now I need help with my brakes!

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2/6/2018 11:40 PM

Finally got the chance to break in/ride my YZ400E this last weekend, and I'm still smiling!! I was generally worried I might not enjoy this old machine much considering I've always ridden modern bikes. To my surprise, I couldn't get enough. Usually I get a bit bored with the vet tracks but it was just right for this vintage machine. For a ground up build, with many guesses on set up, and not knowing what to expect, the day went flawless. The only thing that vibrated loose and fell off in an hours worth of riding was the rear fender! LOL The one area of performance that was a big disappointment was the brakes- not so much bad, as down right dangerous. I thought I would hit up the vital old school brain trust and get some input on things to look for to maybe improve the brakes. I've read all the drum brake related posts on vital before even putting my bike together, so I was feeling confident I would have a good handle on setting these things up. But maybe I'm missing something, or maybe I just need to come to terms with vintage brakes. Here's what I've got:

Front: Proform relined brake shoes, new Terrycable front cable, and new MSR quick adjust modern clutch lever ran upside down. Drum has been trued and shoes have been arced. Brake arm set up so it starts with an acute angle and gets as close to 90 degrees as possible when applied. I wouldn't call the front dangerous, but I was expecting a lot more. I can pull the lever to the bar at 20 mph and while it stops adequate, there is not chance of it locking. and it's a little tough to break with all 4 fingers on the track. I'm worried maybe my front cable is an issue, or maybe the lever lever ratio is off, as I can adjust the lever to the point where one more click and the wheel will drag, yet I can still pull the lever to the bar. Is this normal? any one have any input? Or is this par for the course- welcome to evo-mx?

Rear: The rear is actually worse- same setup as the front, but even less power. The YZ has a pretty short throw on the lever as it is captured between the clutch cover and the lower frame rail, which I think isn't helping. I have the brake adjusted is it is just starting to drag, yet I can press the lever all the way down to the frame. It won't lock the rear wheel at anything over 10mph, and it is almost ineffective at speed. I haven't pulled it apart to check shoes contact yet, but will this weekend. I'm guessing it should be way better than this. Maybe the need more break in? Maybe I didn't bed them correctly? Any input or things to look for?

Heres some pics and a vid: :-)

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2/7/2018 2:19 AM

Take the wheels off and check what the wear pattern is on the shoes. Are they contacting all over or just on one edge? That’ll tell you if they’re working as they should.

In my limited experience drum brakes got better the more you used them and the more you left them alone.

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2/7/2018 8:28 AM

Chuckie,

Here's what I would do.

1) Remove the front wheel & look at the ware pattern on the shoes, make sure that your getting full contact.

2) Knock the glaze & the high spots off the shoes.

3) Order & install a set of Magura dog leg levers.

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00' BMW K1200 RS
83' Maico 490 ( The Project bike)
81' Maico 490- FOR SALE
03' KTM 525 SX (In ICU)
14.5 KTM 450 Fe- FOR SALE

2/7/2018 9:23 AM

I've been riding and racing my '79YZ250 for 10 yrs and I've done nearly everything possible to improve performance and virtually succeeded at every attempt.
The levers are not the problem, I've used "shorties", "longees" and presently use the MSR adjustable.....they all work the same.
The BIGGEST improvement in braking performance is in the CABLE. Throw out those thin cheapie off-brand cables and pay the good money to obtain genuine YAMAHA cables!!
They WORK, period! I use them on all my YZ's.
Same goes for the brake shoes.....OEM YAMAHA all the way. Organic linings are the hot ticket.

If you can't lockup the rear wheel, there is something very wrong with the shoes lining.

Another trick I use is the '80-82 YZ DLS(dual link system) front brake setup on my bikes. You can definitely lock up the front wheel with it.

As other's remarked, make sure the shoes have complete contact with the drum. Knockdown the lining highspots(where worn) with a flat file following the arc of the shoes. Reinstall, test ride and repeat as necessary.Photo

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Larry Navarro - Spring,TX. Damm glad to meetcha!

2/7/2018 9:40 AM

I'm going with the Terry Cable for starters. Try to find an OEM or a heavy duty one from Motion Pro if available. I have had a few from Terry that you could set up to the point that the pads are rubbing the drum yet you could still pull the lever all the way to the grip. What sucks is that I have other Terry Cables that seem just fine.

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2/7/2018 1:01 PM

You could also put the dual actuated backing plate on it from the 1980 and 81 YZ465. Similar to the one on Larry's bike above except it has the brake lug groove in the right position for your original forks. Looks like Larry may have 82 forks on his and that slot is angled too far back, 90 degrees I believe where yours may be 45.

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2/7/2018 1:04 PM

Thanks you guys for the replies and input. Gonna tear into this thing this week and sort this out. Going to start with the front cable first, and see what kinda improvement that gets me. Any ideas on which cable to use? The OE one is obviously not available. There is one on ebay now that is NOS, but literally looks like it has been on the shelf since '78. I looked and the '84 YZ250 front cable is still available, I'm thinking I should be able to make it work. That sound like a crazy route? wfo, which and where are you getting your OE cables?

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2/7/2018 1:25 PM
Edited Date/Time: 2/7/2018 1:27 PM

Chuckie, grab that one from ebay.....the wrapper may look old but I would confirm the cable is new with the seller.
I just installed a new NOS throttle cable on the 250.....the wrapper old and yellowed but the cable is pristine.
I find most everything on Ebay or from motorcycle/powersport dealerships on-line who still stock a good supply of OEM parts. They are out there.
There is quite a difference between cables. Compare side by side, OEM is made up of thicker strand wire for strength and resistance to cable stretch which gives a much more positive feel when pulling the lever.

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Larry Navarro - Spring,TX. Damm glad to meetcha!

2/7/2018 1:25 PM
Edited Date/Time: 2/7/2018 1:30 PM

just wanted to chime in here. I've ridden a handful of bikes with drum brakes, and even the best front drums can't compete with a modern FRONT disk brake. I even tinkered with the idea of building a hydraulic drum, but even that's against AHRMA rules.
The rear drums are fine - yours should be locking up the rear wheel. If not, look at that first, but you will never be happy with a front drum if you've ridden with a front disc all your life. So don't set your expectations too high - you just have to learn to brake sooner on a front drum. Front brakes are one area of a motocross bike that has come a long way.

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2/9/2018 3:32 PM

This is a great place to find NOS vintage Yamaha parts. They sell as yamatopdog on ebay as well.

http://www.speedandsportinc.com/

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2/9/2018 6:33 PM

I agree with all the above. The Terrycable must go !!! I had the same issue,and after investigating we found that the cable was actually stretching when the lever was pulled. Once we put a real cable on it ,the braking improved tremendously. All the other advice above is golden too, but the cable made the biggest difference.

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2/9/2018 7:54 PM
Edited Date/Time: 2/9/2018 7:55 PM

Drum brakes suck. Even the best. Especially if your hauling the mail, they get hot and fade to the point of uselessness in a hurry.
Like the others say, terry cable is a cable in shape and function only.
Had much better luck with motion pro. Sand the glaze off the pads and hub often, maybe try other brands of shoes...
after all that they will still suck. Think of it as charming reminder of the good ole days.
As a friend put it “ you never knew how fast those old bikes were till you tried to stop them!”

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2/10/2018 5:48 AM
Edited Date/Time: 2/10/2018 6:01 AM

As far as braking performance goes, keep in mind that in vintage racing, we are mostly limited to 4-5 laps in a moto so TO ME brake fade isn't much of an issue. It's not like we are riding 40 minute motos. Go to an AHRMA or other "sanctioned" event and watch how fast the old PRO riders push the limits. One in particular racer, factory support rider Trey Jorski, the guy is pushing age 60 and incredibly fast (and harsh) on anything he rides. If anybody had problems with brake fade or whatever, it would be that guy however, it doesn't seem too.

These cats aren't complaining.......


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Larry Navarro - Spring,TX. Damm glad to meetcha!

2/14/2018 6:03 PM

Wanted to post an update so anyone else who stumbles across this thread can learn something. I located and purchased an NOS cable on ebay. When I say NOS, I mean OLD stock. Be curious to know when Yamaha went away from these parts labels:

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I wanted to see if there was a measurable difference between the two, so I worked up a crude way to measure the difference between the 2 cables. I placed a tube over the grip so a tie down would easily slide over it, hooked it to the ball on the end of the lever, and then hung 30 pounds over it. I of course set each cable up exactly the same. The difference was pretty drastic, so kudos and thanks to you guys for diagnosing the cable issue. Here is photos showing the difference:

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I pulled the rear apart and it looks like it has pretty even wear to me. I'm going to order some new OEM shoes to try as well- unbelievably they are still available and are only $26! I scuffed/cleaned everything to try again. I was wondering about the brake pull rod. It has a couple bends in, I'm assuming to tuck it in from your boot better. These bends though will act like springs as the flex when the brake is applied. Am I right in assuming these are meant to be there? Or should I try and make the brake as straight as possible?



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2/14/2018 6:42 PM
Edited Date/Time: 2/14/2018 6:43 PM

Chuckie 108,

The brake pad you show in the photo are not stock Yamaha pads, they are the new compound replacement from Matt Heildberger & are what you want to run, they do take a little while to seat/break in.

Don't bother buying stock pads, you'll be disappointed. just keep working those.

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00' BMW K1200 RS
83' Maico 490 ( The Project bike)
81' Maico 490- FOR SALE
03' KTM 525 SX (In ICU)
14.5 KTM 450 Fe- FOR SALE

2/14/2018 6:51 PM

bigmaico wrote:

Chuckie 108,

The brake pad you show in the photo are not stock Yamaha pads, they are the new compound replacement from Matt ...more

Thanks for the input! Any opinion on the brake rod?

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2/15/2018 1:52 AM

chuckie108 wrote:

Thanks for the input! Any opinion on the brake rod?

Well, they would engineer some flex into the rod to make it harder to lock up the back brake unintentionally. Evaluate how it's working for you--

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2/15/2018 7:09 AM

Before tightening the front axle, with the wheel off the ground spin the wheel fast and apply the front brake a few times, then tighten the front axle while holding the brake

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If you like uncle tony's meatballs, you'll love his sausage

Now that's Italian

2/15/2018 9:12 AM

We found getting the braking surface machined flat across and perfectly round, then match the shoes getting the flat actuator at the right angle to be a way to get the best drum braking possible. Obvioisly including good cable etc already mentioned. Tho its no simple task and requires time and skills..back when i was doing vintage in oz i was one of the first to run a double leading shoe brake on my yz250f79 but they banned them the next year..sad

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2/15/2018 9:19 AM
Edited Date/Time: 2/15/2018 9:21 AM

Nope afair the brake rods were dead straight..dont think i ever saw japanese engineering that inprecise? But it was years ago so i stand to be corrected...now thinking about it some may have has tight dog legs to clear things but they would be less prone to unwanted fkex..

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2/15/2018 5:47 PM
Edited Date/Time: 2/15/2018 6:29 PM

bigmaico wrote:

Chuckie 108,

The brake pad you show in the photo are not stock Yamaha pads, they are the new compound replacement from Matt ...more

WRONG Howard. Maybe your Maico's had ill-engineered brake shoes to begin with so aftermarket was the only choice to HELP performance.
I know that OEM Yamaha cables and brake shoes are superior to aftermarket.
Chuck took my advise on cables, he can do the same when it comes to my experience on brake shoes. Even Scott Sears, premier YZ builder and owner of XYZ uses OEM Yamaha pieces on his bikes. Why, because they stop.
Chuck, I also notice you chose the MSR levers over the earlier suggest Magura levers. Your cable test pretty much proved the lever type a moot point.

Like I noted in my earlier post, I've used them all, no difference in any of them. I currently use the MSR merely for "on the fly" adjustment, plus they look trick. However, if using the OEM cable, the lever slot the cable slips through will require some widening with a small flat file as they are designed for the thin aftermarket cables.

For ANY Yamaha build, NOS OEM parts are top quality.........they worked for Bob Hannah. Ahh wait I think he later used the Sunline levers.......but that was Superman on those bikes.

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Larry Navarro - Spring,TX. Damm glad to meetcha!

2/15/2018 6:08 PM

Uncle Tony wrote:

Before tightening the front axle, with the wheel off the ground spin the wheel fast and apply the front brake a few times, ...more

Not necessary to "overtighten" the axle. It's held in place with the pinch-joint bolt(s). Snug the axle tight, maybe 10-15 ft/lbs, then the tighten the pinch bolt(s) as required.

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Larry Navarro - Spring,TX. Damm glad to meetcha!

2/16/2018 4:12 AM

Have same problem with my CR480, will try new wire.
Have anyone compared Venhill to oem?

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2/16/2018 5:46 PM

Both of you built a couple good looking Yamahas
I know people have had DLS brakes work well. I just never felt one feel anything but a mushy mess. I used to think Honda drums worked the best and Yamaha a solid second. For some reason I had a extra YZ front wheel back in the day and I used to run it on my 81 RM because I liked the front brake better

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2/17/2018 7:19 AM

There will never be anything better in braking than the disc. I also ride a '95 CR250 so I'm familiar with both aspects of oldschool and modern. I've done the best as possible for the YZ and hope my info helps others bypass the hassle AND expense in finding the optimum combination.

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Larry Navarro - Spring,TX. Damm glad to meetcha!