Re-thinking my rear brake.

But yes, I do want a good rear brake. It seems other people that change to a rear disc brake do too. But I want to keep it close to stock. I never slam on the brakes, even in a panic stop. We all know that as soon as a tire starts to break contact and slide you lose braking. My rear brake is not broken, it's just not as effective as it could be, or could have been from the factory. That translates to increased stopping distance when it's do or die. I wish the XS had the rear braking power of the Honda, it's light pedal pressure and movement to bring that wheel into serious play. I would say if your rear is trying to catch your front, your flat tracking or too heavy handed on the front brake. That's real easy to do with two fingers on the front brake when your rear brake "feels like" your stepping on a plum with three inches of pedal movement or somebody greased your shoes.
I'm not a betting man xjwmx, but if I were, I'd bet I have had formal training in panic braking and collision avoidance since you have? I also think all of us here believe "If it ain't broke, don't fix it!" But we do modify the hell out of it. Maybe I should have went for an expensive set of shoes when I built it up last year?
I don't know, but next time the rear wheel comes off I'm gona be inspecting things real close.
 
If you ever do find yourself going down the interstate at 80 mph sideways, don't release the rear brake. Keep it locked. Releasing it will cause the rear to swing back in line suddenly and may buck you off. The thing to do is let up on the front a little to let it outrun the rear and line it up again. You can practice this in large parking lots. The cops will show up, but half the time they have a motorcycle license and will understand what you're doing and your explanation. You only have to appear sane. You will end up riding with the cop, and make contacts and end up on the city council. They may even put you in charge of the mayor's illegal gambling operations. Don't cross them or you're back to sliding down the road sideways. At best. At worse, you could just "disappear".
 
thuban said:
But yes, I do want a good rear brake. It seems other people that change to a rear disc brake do too.
Click to expand...
Rear disk on non-abs bike is 100 pure marketing and potentially dangerous. I spent minutes of my life explaining it all. Don't make them be wasted.
 
"...going down the interstate at 80 mph sideways" ... :yikes: I don't think I've ever seen the need to run my XS to 80 MPH, much less lock the rear brake to see what would happen. I guess someone had to test it and my hats off to ya'. I'm not a brake expert. I'm not a chef either but I know when the foods bad. I've noticed the whole two wheeled platform is "potentially dangerous". That fact is not lost on any of us that walks out in the morning, looks at the bike and says, "Nope, think I'll take the car today." We've all seen the modern Knight blasting down the highway on his too-hot-to-trot steel steed with his ball cap turned backwards. Cool beans and each to his own and Oh, BTW, we got ABS for ya! The way your riding and the way the weather is looking, you just may need it! I wonder if he knows anything about the judicial use of a GOOD set of front and rear brakes combined with engine braking on a less than optimal road surface? We've all ridden different bikes or new bikes and were impressed with some quality about it. I don't think anyone will ever be guilty of coming away, after a ride on my XS, and saying, "boy, it's got a good rear brake!" But as I said, I'm not a brake expert and I apologize for whatever minutes you spent on brake edification. It evidently, was totally lost on my rear brake.
 
thuban said:
I've noticed the whole two wheeled platform is "potentially dangerous".
Click to expand...

thuban said:
don't think anyone will ever be guilty of coming away, after a ride on my XS, and saying, "boy, it's got a good rear brake!
Click to expand...
:laughing:
With you thuban. Never had an XS drum rear brake be too powerful. Rear disc perhaps.
A very strong rear disc is a fantastic thing to have off road! A YZ250 definitely benefits from that. On road, I'm very okay with the weakness of the XS rear drum. I prefer to use the rear brake only even, while stopped at intersections :D
I hope you get your shoes working adequately. Try flipping em over even if you think they are thick and in good shape to run further. Or buy new OEM shoes.
-R
 
xjwmx said:
Rear disk on non-abs bike is 100 pure marketing and potentially dangerous
Click to expand...

I trail brake on entry.
There is only just so much rear contact patch available to the XS with stock swing arm and sprocket spacing.
On exit the rear brake is traction control.
In effect I am traction control.

Granted this isn't for beginners or even for stock engine output. I've been doing this for 45 years and the least of my engines is around 55 HP and near 70 HP for the alcoholic. Both engines have enough compression braking to pulse the rear end on entry so the clutch is in and the rear brake is used to establish entry and left on to near apex and then reapplied on exit to limit wheel spin.

In the end the rear disc is over all simpler, easier to manufacture, easier to service, and if designed with any intelligence lighter with a significantly lower un-sprung weight penalty.

I don't suggest this riding style for any but the experienced rider and/or a highly modified engine. It's actually a waste of time, tire, brake pad and rotor with little to gain other than attacking a corner.
.
Even for the experienced rider adjusting to aggressive trail braking can lead to embarrassing and possibly painful results.
 
kopcicle said:
I trail brake on entry.
There is only just so much rear contact patch available to the XS with stock swing arm and sprocket spacing.
On exit the rear brake is traction control.
In effect I am traction control.
Click to expand...
It's interesting what different people do. My first experience on a bike was at MSF, so I do what they do, sort of religiously, including some proselytizing. In normal circumstances the rear brake doesn't need to be strong. In emergency circumstances it isn't doing any good if it's skidding and it certainly will when all the weight has shifted to the front, so it doesn't need to be strong there either. So practically speaking I see nothing to gain by making it stronger. In fact I actually weaken mine on purpose by having the pedal mounted pointing a bit downward so if I were to really get on it my foot is pointing quite a bit downward which is much weaker than if the foot was level
 
Good brakes are like prophylactics and spurs. Better to have them and not need them, than need them and not have them. Like gggGary said, rear brake is adequate. I just looked at the factory brakes that came off the bike. They are worn perfectly in the middles. There was no more meat on one end that the other. It looks like they were doing the optimum they could do.
 
thuban said:
Good brakes are like prophylactics and spurs. Better to have them and not need them, than need them and not have them. Like gggGary said, rear brake is adequate. I just looked at the factory brakes that came off the bike. They are worn perfectly in the middles. There was no more meat on one end that the other. It looks like they were doing the optimum they could do.
Click to expand...
There are little things that will strengthen it slightly, like make sure the shaft that goes into it is smooth and greased a bit. If you arrange the arm that goes onto the shaft so that it's 90 degrees to the pulling rod when the shoes are against the drum, it gives it the most leverage
 
Yep, Xjwmx, I've done all that and double checked it. I'm looking for better engagement, less pedal movement and less mush. Marrying front braking with engine braking and down shifts are a piece of cake. But it's no joy when your toe on the rear brake pedal is reaching toward the pavement. I grew up on gravel roads. It didn't take long to learn to stay off that front brake.
 
You haven't given any info on the year of your brake plate and/or the parts in it. Maybe you've got some mismatches? You said you marked the cam face with a dimple when disassembling things and could see no other dimples present. All '80 and older cams should have the dimple plainly stamped on them. '81 and later cams will have a faint dimple but more importantly, will be missing a spline for installing the shoe wear pointer. The missing spline should face up .....

rEoQHgG.jpg


There were variations in the cams used as well. The two later cams will swap but must be used with their correct spacer washers .....

hWi5STC.jpg


jskirgT.jpg
 
It's a 77. No dimple I saw. Funny, the book shows the arm at other than 90 degrees and more like Machine has his set with the arm back about the edge of the hub. ( Yam service Manual 74 - 77, 1st edition Oct 75 p. 5-115.) More info p.5-138 and 139. No wear indicator. original equipment.
 
While 90° between the arm and rod will give best leverage, you usually can't get it set exactly there because of how the splines mate up. Usually, you end up with it making a slightly less than 90° angle and moving through or to the 90° angle when applied.

As you can see in my 1st pic 2 posts up, the dimple on the later cam is very lightly stamped and barely visible if you look straight on at it. Maybe yours got a light stamping as well. Look down at it from the side and you may be able to see it .....

YRhMwgx.jpg
 
It's funny that your '77 plate is so troublesome. Out of all the ones I have tried, my '77 one works best, lol. But, that seems to be changing now that I switched all my cams around to the "right" way. My TX750 brake is getting better by the day now.
 
Anybody with experience in the grippiness of various makes of shoes?

Also, it occurs to me that a simple way of making it stronger would be to custom make a longer arm (the arm between the shaft and the pulling rod) to increase the leverage. Interesting that there isn't one...
 
Last edited:
These are my match marks on both the shaft and the arm. They went back the same way I took them off.
brake arm.jpg
 
I have XS650's with both drum and disc brakes.
The disc is a stronger brake and is a bit easier to modulate.
The drum takes a bit more pedal effort to get the same amount of braking.
The 75 I did the conversion to a disc brake. The drum brake is more than enough brake. The conversion was a good learning experience but not enough improvement to be worth the effort for the casual street rider. Those with a more racing type of experience may find the disc to be worth it.
Leo
 

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