Brake options for 74 TX650 ?

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TAlber8

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What are option for swapping brakes on 74 TX650?


Original was pitted and seized, cheap knock off replacement was filled with problems, seals that wouldn’t hold pressure etc... spent a lot of time swapping lines, masters.... just want to move to a new direction.


I would like to avoid swapping forks....
 
If you search "brake upgrade" on this forum you get something like 18 pages of discussion and options. Personally, I've had no problems refurbishing my TX brakes with quality stock-appearing components. Even right out of the box, TX brakes always exceeded the capabilities of the suspension.
 
If anything, the early XS2-XS650C calipers are superior to the later single piston calipers. TZ race bikes used the same 48 mm/ opposed piston calipers as all XS models with disc brake +34 mm forks. Just like RD350 and 400 up to 78 did. The change that came with the 77 XS was definitely no upgrade, except maybe from a bean counter perspective.
 
hovel said:
If you search "brake upgrade" on this forum you get something like 18 pages of discussion and options. Personally, I've had no problems refurbishing my TX brakes with quality stock-appearing components. Even right out of the box, TX brakes always exceeded the capabilities of the suspension.
Click to expand...
Yeah I didn’t see a whole lot on the early ones, mostly the later.
 
jetmechmarty said:
Except for the unsprung weight reduction and proper positioning of the caliper behind the fork leg.
Click to expand...
The later single piston caliper may have been a little lighter, but the discs cannot have been. The earlier discs had an alloy hub, while the later are all steel. So especially in dual disc configuration, the total unsprung weight is ridiculous. And didn't the 650 C already have the calipers behind the fork sliders?
I actually bought a reproduction alloy caliper for my RD from Economy Cycle, and I also got hold of a disc hub from a TX or 650C, and had ISR of Sweden make a modern, 5 mm thick disc for it, which I planned to use on the RD. This turned out to be more complicated than I expected, that disc is still on the shelf.
If I had an early XS, that is the route I would go for. A single 298 mm disc made from a modern (Swedish) steel, a lighter aluminium reproduction caliper, the best pads I could find, a braided teflon hose and a 12 or 13 mm bore master cylinder (Brembo, Grimeca, or other)
 
You could upgrade to a brembo or tokiko caliper with some adapters, but this would not allow you to run the factory front fender support. If you are trying to keep it looking original then i think you are stuck with the factory caliper. As others have said, the earlier twin piston calipers that it came stock with are better than the later single piston calipers that came on the 35mm.
 
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arcticXS said:
So especially in dual disc configuration, the total unsprung weight is ridiculous.
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It's 20 lbs for dual calipers and rotors, so by today's standards it is ridiculous.

arcticXS said:
And didn't the 650 C already have the calipers behind the fork sliders?
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Yes. The XS650C had the updated caliper position.

arcticXS said:
If I had an early XS, that is the route I would go for. A single 298 mm disc made from a modern (Swedish) steel, a lighter aluminium reproduction caliper, the best pads I could find, a braided teflon hose and a 12 or 13 mm bore master cylinder (Brembo, Grimeca, or other)
Click to expand...
It sounds great if you can pull it off. Not everyone is equipped with your skills. Certainly, there is a great deal of room for improvement.
 
Yes, the early disc is lighter, by nearly a half pound. I've been toying with the idea of adapting one for use with the later 35mm fork and caliper. It may actually be quite easy. The big hurtle is the early and late discs have a 5mm difference in offset. You can get 3mm of that back by simply flipping the disc over on the carrier. The last 2mm might be gained by simply slipping a washer on the axle on the right side. It may just be this simple although I haven't tried it yet, but I'm considering it. I think the early disc looks much nicer as well.
 
my scale shows a 3.5 ounce difference.
A much greater weight loss (2.5 pounds!) can be had going to a later fzr rotor, note a spacer blank included in weight..
the spacer is available or a simple lathe project.
note all rotors pictured used but not worn out.
DSCN0482.JPG
DSCN0481.JPG
DSCN0479.JPG


Kinda related; I just spent 2K miles on an XS1, about 700 of that spirited group riding in twisties, the drum was "not that bad" I've had cruisers with disk brakes that required more effort to stop.
 
953B935E-D845-4CCC-A917-43083E5361A4.jpeg.jpg

SR500 5mm x 2 plus calipers.
Adds up but in reality does a guy even notice? I just do this because it is very easy and then the original 14mm master cylinder works much better. And it looks stock. And the left fork leg gets its unused tabs used.
(cuz those empty left side fork leg holes bug me lol)
 

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An advantage to dual disks is less fork deflection under heavy braking. Prolly not an issue for most of us. But a ride long ago while proving the Mighty XS could shame squids on liter class bikes, I dealt with nasty head shake on brake release/turn entry. I now think a single disk on resto mod was a lot of what was going on as the wound up fork released it's twist from heavy braking force.
This exhibits none of that shake...
front detaila.jpg

Fork brace doesn't hurt either but not sure how much it stiffens things.
After 2K on the XS1 riding this 90 miles Thursday felt deluxe!
 
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I actually really like the visual appearance of the crazy old school forward mounting of the caliper, in relation to the fork, on my TX650A. As I ride it more, the braking power with new pads and the stainless braided line upgrade I did, is not that bad. It just forces me to ride slower, which was part of the overall plan. It is definitely NOT the Honda 919 I sold last summer. I just have to keep that in mind. :rock:
 
Despite what I just wrote, that front end looks great gggGary! All of these bike look so damn cool in their own way. I don't think there is any wrong way, so long as it's safe.
 
arcticXS said:
The change that came with the 77 XS was definitely no upgrade, except maybe from a bean counter perspective.
Click to expand...
Well, have only owned 77 and up and have learned just how easy it is to have a light dual caliper bolt on with all
stock Yamaha components.
20210515_133221.jpg

The 77 up Aluminum single piston calipers are very light and worked well on many Yamaha models over years.
It just makes me feel so embarrassed to read what a mistake I've made.. over and over.
20210515_133403.jpg

:shrug: trust me, it brakes just fine. And I will upgrade lines now that it's all proven out to be caliper piston and master cylinder functioning leak free.
 

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The fork brace really makes a notable difference if you modify the stock forks ie straight rate springs and cartridge emulators. I likely won’t add one to my stock Special, but reserve the right to change my mind.
 

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