Making A Right Fork Leg For Dual ATEs

[Foot dragger]

Originally Posted by PaulRS

Why bother upgrading a marginal brake by adding another one?

I'd get me a set of Brembo sliders, calipers, disks, or whatever comes along, dump the cable operated MC and fit a bar mounted one.
And if it isn't a straight fit, you can always mix/match/machine to make it fit.

BMW is like Lego for big boys.

Paul.

Yah,but putting real brakes that stop pretty hard on forks barely strong enough for what they already have could be an issue with flex. I do agree the ATE's are kinda goofy and weak though.
It also seems like welding on the lower fork area could lead to warpage issues,I guess an machinist/welder would contend with this.

[Stan_R80/7]

I am considering (i.e. in the process) of doing this conversion. My reasons are: cost and availability - $400 for a Brembo front set of lowers is a bit high and left lowers are easy to find; better brakes - I can live with decent (still, not great) ATE dual brakes; it's period correct - not that the bike has any collector value, but it looks right; it is not permanent - the original right lower can be reinstalled. Drilling and reaming a new hole is no problem and cutting off the tang to weld on the other side may just be the excuse I need to get a spool gun. I think the tang has no function - other than looks.

I have another brake line and rotor with pads, so another ATE caliper, a piece of M10x1 steel brake line, and a brass brake line tee are needed. I got a set of /7 lower forks for $80.00 shipped and can live with losing that amount if this doesn't work out. I'll probably swap the ATE caliper to the right side to test the modified fork and rotor operation before finishing the conversion.

[disston]

You need five (5) longer bolts that hold the rotors on.

[Voltaire]

After racing my conversion for a year I'm happy with it, can't ever see myself converting to Brembos.Although ATE's in their original form combined with age are not flash, once you go to 13mm m/c, stainless lines and CAST IRON discs they work a treat.

[Kai Ju]

Originally Posted by Voltaire

After racing my conversion for a year I'm happy with it, can't ever see myself converting to Brembos.Although ATE's in their original form combined with age are not flash, once you go to 13mm m/c, stainless lines and CAST IRON discs they work a treat.

+1

I got lucky on my conversion, a gent had an NOS left leg for sale that I was going to do the conversion on, but when it arrived in the mail it turned out to be a right side leg........
I modified my 13mm under tank M/C to run a double banjo line out of the original hole and I'm pretty happy with these 37 year old brakes.

[daveoneshot]

Yo, Kai Ju,any chance of a picture of your M/C banjo lines ?? I would like to do the same brake mod to my R 100/7 and could use some more education ....sources for the fittings, and any special tweaks I should know, thanks, Dave.

[Wirespokes]

Originally Posted by Stan_R80/7

I think the tang has no function - other than looks.

Oh, but they do have a function! They keep the caliper from flopping up or down. The caliper also swings, and has to slide easily on those 'wings'.

[Stan_R80/7]

On my /7 left front fork, the tangs look like they hold the outer pads in place. But, there is a gap between the pads and tang, so it is not clear at this point how much of the tang is critical. Both an upper and lower tang need to be moved.

Upper tang:



Lower tang:

[AntonLargiader]

Originally Posted by Stan_R80/7

...so it is not clear at this point how much of the tang is critical

Look at how the pad is mounted to the caliper, and imagine the braking forces, and then it will be clear.

[Stan_R80/7]

Upon closer examination in the light of day, the lower tang has 0.011" clearance to the pad but the upper pad touches the upper tang. Thinking about reaction forces, the upper tang takes the rotating force from the disc to the pad. Good to know before modifying anything.

[Kai Ju]

Originally Posted by daveoneshot

Yo, Kai Ju,any chance of a picture of your M/C banjo lines ?? I would like to do the same brake mod to my R 100/7 and could use some more education ....sources for the fittings, and any special tweaks I should know, thanks, Dave.

Here you go. Be aware that the banjo bolt setup needs to have a flat surface on the master cylinder to seal. I did mine with a file. I crammed a short rubber plug into the hole and then used a file to level out the seal surface on the master cylinder. I verified it's flatness and squareness by using a thick spacer over a 10x1 mm bolt. I screwed it in the hole and then checked for airgap with the spacer seated on the master cylinder. Hasn't leaked, ever.
Also, left and right caliper may look the same, but they are not. I bought a left caliper thinking it would be a straight install.
The bleed nipple hole is opposite and it's machining is different from the hole for the compression fitting on the brake line.
I was able to use a drill bit resharpened to match the angle of the bleed nipple seat surface and centered it in the hole with a bushing while I hand reamed the seat for the bleed nipple, sorry no pics of that process.


Banjo bolt set up and hose routing





Master Cylinder seal surface before filing



After



Caliper installed





The brake hose was made for me by a local shop, while I waited
He may still have the specs, cost was about $80.00 for the hoses, fittings and the rubber grommet for the brake hose in the stock guide.

[Wirespokes]

Also, left and right caliper may look the same, but they are not. I bought a left caliper thinking it would be a straight install.

Something must have been weird with your second caliper - there are no lefts or rights. They're all the same. I've never had an issue with a caliper not working on a particular side. Also, if they were handed, I'm sure they would have been stamped or some indication would have been placed on them.

[Kai Ju]

Originally Posted by Wirespokes

Something must have been weird with your second caliper - there are no lefts or rights. They're all the same. I've never had an issue with a caliper not working on a particular side. Also, if they were handed, I'm sure they would have been stamped or some indication would have been placed on them.

Next time you get the chance to look at one examine the bottom of the two holes. The one for the bleed nipple has a seat cut in it for the bleed nipple.
Mind you, I just went to Max's Parts Catalog to prove my point with the part number for the right side being different from the left only to find out that it isn't.
I know I didn't imagine the difference or I wouldn't have gone through the trouble of making the tooling for cutting the seat.
At least I sure hope so................

[daveoneshot]

Great pics and info about the brake job.....thank you, Dave.

[Kai Ju]

Originally Posted by daveoneshot

Great pics and info about the brake job.....thank you, Dave.

You're welcome, glad to help.