Greyone
XS650 New Member
Any help on improving the front brake performance would be greatly appreciated, are pads a good first option? Is a twin disk wheel better? New caliper? Twin pot etc. Oh, and thanks for letting me join the forum.
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Single disk 1974 front brake
- Thread starter Greyone
- Start date
R&R caliper full strip remove pistons and seals, clean behind the seals, so you are positive both pistons are moving freely. If there is ANY chance fork oil got on the pads, replace em. Then an SS line and change master cylinder to one with a smaller bore.
I agree 100% with what Gary just said. On my RD, which had the exact same caliper, I use a Brembo MC with a 13 mm. bore, and it works fantastic.
Adding a second disc and caliper is like welding a 6-7 pound anvil to your front fender. Which will not improve the front suspension, to put it diplomatically.....
So do not do that!
Adding a second disc and caliper is like welding a 6-7 pound anvil to your front fender. Which will not improve the front suspension, to put it diplomatically.....
So do not do that!
I assume its a US import. UK didn't get the TX74A. ................Could you confirm??
Also doesn’t hurt to resurface the disc. I just use an orbital sander.
Some people say stick with the single disc and improve it.
I'm happy with the Euro-spec double discs, but they've been improved by an overhaul and a 5/8th" master cylinder instead of the 11/16" one that was there.
I'd briefly tried a 14mm m/c and the bike nearly stood on its nose, but there was too much lost motion, so the lever came worryingly close to the bars on full stop. The 5/8" was just right -plenty of feel and bloody good stopping.
However, I'm not one to be bothered by the extra weight, I don't notice it.
I hope someone will confirm, but I do believe the Euro spec rotors are smaller than what was on the US models, making them lighter. That means the fork lowers don’t interchange either. The caliper mount positions are different than those with the larger rotor.
What model is yours? Mine is a 77D model, and had this dead annoying clunk when the fork topped out during acceleration, and the fork worked rather poorly on bumpy roads. After getting rid of near 5 kg of unsprung weight, and installing emulators and new springs, it improved a lot.
I'm thinking the general theme here is; I made "some improvements" till the braking was "good enough" for 70's power and handling.
story: I have a pair of smooth, slightly banked, left, right, 90 degree corners on the way to town.
My "comfort speed" through those corners varies by bike with about a 10MPH range depending on mount.
When I had a barely streetable race bike a few years back, the speed notched up another 10MPH with no difficulty or fear.
It was clear that such a bike was not a good street ride for many reasons.
Go back to an XS and boom right back down to the speed that felt right on THAT BIKE.
A point in favor of dual disks; with noodly period forks, a single disk, used hard, WILL twist the steering. Not really noticeable till fast; throttle on to hard brake transitions come into play.
story: I have a pair of smooth, slightly banked, left, right, 90 degree corners on the way to town.
My "comfort speed" through those corners varies by bike with about a 10MPH range depending on mount.
When I had a barely streetable race bike a few years back, the speed notched up another 10MPH with no difficulty or fear.
It was clear that such a bike was not a good street ride for many reasons.
Go back to an XS and boom right back down to the speed that felt right on THAT BIKE.
A point in favor of dual disks; with noodly period forks, a single disk, used hard, WILL twist the steering. Not really noticeable till fast; throttle on to hard brake transitions come into play.
Agree with you, Gary. I guess the single vs dual disc discussion is about finding a compromise between conflicting priorities, such as originality, looks, budget, brake performance, suspension performance, and performance in general (read weight influence on acceleration).
Personally, I tend to lean towards the performance side of things, as reduced weight helps acceleration, suspension AND braking. Others get their knickers into a twist if any non stock part is used.
Personally, I tend to lean towards the performance side of things, as reduced weight helps acceleration, suspension AND braking. Others get their knickers into a twist if any non stock part is used.
We all like to do our own thing. Depends on whether your want originality, Original look or a genuine performance gain. Simple remedy is as @gggGary and @Raymond says and just change out for EBC disc and pads. You could also change the master cylinder for more performance gain. These machines generally only need one disc for the power on offer. I have upgraded to larger drilled Brembo single disc and 4 pot caliper with Honda Nissin MC / levers; it all works a treat, but is no way original.
For a lot of performance gain, you can replace the frame. Get one that can handle really stout forks with monster brakes.
Squeeze in a late model high performance/low weight motor and you'll have it................ ;^)
One thing that sort of makes mods and upgrades somewhat attractive, is that they are all 100% reversible. At least as long as you keep the stock parts safely stored.
In any case, resurfacing the stock disc, good pads, braided hoses and a smaller MC is a good start.
When it comes to the 76 and older XS with a single disc, one thing really plays in the step by step methods favor. The piston area of the stock 2x48 mm XS/RD/TZ(!) caliper is exactly the same as a 4x34 mm Brembo caliper. So a 12 to 14 mm MC is still a perfect size should someone want to upgrade to a modern caliper later.
In any case, resurfacing the stock disc, good pads, braided hoses and a smaller MC is a good start.
When it comes to the 76 and older XS with a single disc, one thing really plays in the step by step methods favor. The piston area of the stock 2x48 mm XS/RD/TZ(!) caliper is exactly the same as a 4x34 mm Brembo caliper. So a 12 to 14 mm MC is still a perfect size should someone want to upgrade to a modern caliper later.
Drill the disc to aid cooling, clean the pads off and slightly reduce weight. Looks pretty too!
My 650b brakes were woeful, I've stripped and cleaned everything, added braided lines and bled them all through along with my drilled disc. I've not tried them out since however since I got carried away removing bits to make them more shiny.
My 650b brakes were woeful, I've stripped and cleaned everything, added braided lines and bled them all through along with my drilled disc. I've not tried them out since however since I got carried away removing bits to make them more shiny.
Attachments
Greyone
XS650 New Member
Yes, I believe it is, been in the UK for about 7 years.
US standards, (74-79), have different front forks to the Euro/UK 75-82 standards.
Now we will go back and answer Marty's question as well.
All is revealed in this link. Scroll down to the 75/76/77 years. Has pics of the front forks with differences
https://www.xs650.com/threads/xs650...workshop-manuals-and-other-information.30569/
