75 drum brake ?

So im trying to figure out the drum brake on my 75 xs650. After a little tinkering it seems to work realtively well, considering its just turning the wheel by hand. I have looked at numerous bikes, as well as on chopcult... for the drum brake, does it matter which way the drum brake actuator is facing up or down? To engage it, can it be turned clockwise or counter? Just trying to figure out the cleanest way for my linkage. Some I see its up, some I see its down, up would be turning it counter clockwise, down counter clockwise? Does that matter? Hopefully my explanation makes sense, otherwise ill snap some pix tonite.

If you're referring to part number 17 in the parts catalog (attached pic), it points down. But I'm not sure if that's what you're asking. That's just the way it is as stock.

It'll work either way.

In the stock configuration, under hard use, the rear drum brake can see up to several hundred ft-lbs of braking torque, which is resolved thru the brake stay, at half that torque arm, resulting in upwards of about a thousand pounds of tension in the brake stay. With the brake lever down, the brake actuating rod helps to unload that brake stay tension, by up to a couple hundred pounds.

With the brake lever pointing up, brake actuating rod tension adds to the brake backing plate stopping torque, adding to the tension in the brake stay. Not the better way.

When the brake lever rotates the brake cam, the shoes are expanded, but one shoe receives this expansion force from the outside of the cam/shoe contact area, the other shoe receives it from the inside. A very subtle difference in shoe force and spread travel result.

Most brake cams have a simple rectangular rounded-end profile. Some have a slightly modified profile that makes the shoes expand equally. Don't know about your particular model, but you may want to see if yours has this modified profile. If so, operating the brake lever in reverse direction may produce a shoe spreading imbalance and reduced braking action.

A lot of folks run the brake lever pointing up, or in strange directions. Just want to help you to understand the mechanism and its loadings...

Ill have to post a pic of what I got. Thanks all for the info. I am being not smart here and running no front brake, so ideally the best way to run it is what I plan to do. Although I am missing a couple pieces going off that diagram. My Clymer doesn't show anything. Ill post what I have hopefully tonite/tomorrow morning and maybe I can get this figured out. Note to self, never get in over my head again

You can go thru these 'manuals' threads and download a lot of helpful info:

http://www.xs650.com/forum/showthread.php?t=41
http://www.xs650.com/forum/showthread.php?t=30569

More drum brake info:

http://www.xs650.com/forum/showthread.php?t=34053

Can also use the forum's google search on: "drum brake"...

If that's going to be your only brake then you better do a thorough cleaning and service on it. Here's some info .....

http://www.xs650.com/forum/showthread.php?t=25632

Thanks guys. Ill definitely go through the threads you posted. I plan to replace what I have to with the brake, I did with everything else on this bike so why stop now. Looks like I have some reading to do. Im sure ill have a question at some point. Thanks again!

The XS650 drum rear brake is not all that great even when it's just a "helper brake". Just sayin'

Well the plan is to get it finished so I can sell it... little one on the way, and a 66 genny shovel is sitting next to the yammy project. But I hear ya gary, not a fan of drum brakes to begin with, but to swap it over... more money than I want to put into it. Sadly that will be the next guys issue. Hope that doesn't sound evil...

Ok,
so I have a couple questions issues... the joys of trying to figure this out on your own haha. So I have a sissy bar I made for this, brake seems to work, besides I haven't gone through it yet to clean it but that's here nor there. So does this look ok? Or does anyone care to share there drum brake set up? I have a feeling I have to grind off the tab for the brake stay and move that... just sort of figured that out last night. I am praying that's not the case. Thoughts?

Your best brake stay geometry is when the stay, and a line thru the stay end and mid axle position, are at a right angle. So, in your pic, it looks like the stay is about 1-1/2" to 2" too long. Could shorten it, or reweld the frame tab more forward to get this ideal angle, putting the backplate arm pointing down. This will rotate the backplate about 30°, putting the brake lever in a better/lower position, so its pull linkage will be a little more below the axle...