Boxerworks.com

1 more disc
5 longer bolts to hold the disk on
1 right side lower fork leg designed for a caliper (or you can make one from a cheap left side leg like I did...but that's another story)
1 caliper (right and left are the same in ATE, you just have to switch the bleeder and pipe).
1 right side pipe and mount ( or bend one yourself to mirror the left side one)
1 more brake hose. (replace both hoses with aftermarket stainless ones. They're cheaper and better.)
1 dual hose master cylinder (or machine a single one for two hoses...or use a T in the hose to accommodate the other hose).
Most of the expensive stuff can be gotten at a fair to cheap price on eBay.

As I read through the posts, I agree with what Max Headroom wrote. He hits the nail on the head. My first BMW, which is now essentially, a different bike, was a 1974 R90/6. It had the smaller flywheel bolts, the smaller spigots, the wonky transmission, the 14mm axle and the switch gear complained about here. I never had one problem due to any of those things. I did change to a dual disc ATE system that I find barely acceptable. The dual disc front end has the 17mm axle.

When I got my bike, it was my only motorcycle. I had owned some Japanese bikes before it, but had not ridden for several years. The turn signal switch is fine. I can't believe that anybody would be all that bothered by it. And, I do find the way you turn the switch to be logical. You flip it up for a left turn, the same direction you would turn a car steering wheel, and down for right. The one and only way it is a problem is if you have multiple bikes and your mind doesn't switch back and forth easily.

My R90/6 was an eager and willing companion. It eventually morphed into the R90S that I have. I agree with Ken Whitehawk's comment that they are soulful bikes.

Chuey

Edit: I forgot to say that if you are not concerned with keeping the fork/brakes looking stock, I think you can use a later model fork. I bought a complete one for less than $200.00.

Chuey wrote:I did change to a dual disc ATE system that I find barely acceptable.

I disagree. Properly adjusted the ATE dual brake is more than enough. You won't do front wheel stands, but after riding a single for almost 18 years, the dual feels like it will put you over the handlebars when you come to an emergency stop.
The only down side I have experienced is that the number of deer crossing my path has grown substantially since I made the conversion.

mattcfish wrote:Properly adjusted the ATE dual brake is more than enough. You won't do front wheel stands, but after riding a single for almost 18 years, the dual feels like it will put you over the handlebars when you come to an emergency stop.

Yeah, we've had this discussion before. All I can say is: anyone who believes that a dual ATE brake is "more than enough" is not anyone I want designing my motorcycle brakes.

+1 to Major Softie

Where I live in the south of England, the roads are fairly narrow and the traffic is heavy. On my R90/6 single ATE disc braked bike, I went through all the standard "upgrades", 2nd disc, cast iron rotors etc. but still found the brakes insufficient, even dangerous. When I switched to a Brembo front end, it was a night and day difference. It totally changed my riding experience.

Moto Guzzi and Ducati had Brembos in '74: BMW should have specified them.

Sam

Duane Ausherman wrote:

Zombie Master wrote:The single disc brake on the 74 seemed a big improvement over the old drums. quote]

ZM, you are about the last person on earth who thinks that the 74 disc was better than the drum on the /5. Even the BMW literature showed it stopped in a longer distance.

Rolling backwards the disc was better.

I would take the time to set up the caliper and get full pad contact with the disc. Seemed a better brake than the drums to me. I wonder if I had found a better performing pad. Long time ago.

At the risk of a thread hijack (as well as dredging a topic previously well-covered elsewhere), the design fault of the twin Ate caliper setup is the m/c, due its diameter being too big to give a reasonable ratio IMHO. Changing the m/c for a smaller diameter item, or better still, moving to a later handlebar m/c improves the Ate brakes exponentially. My twin 40mm Ate front end with 13mm handlebar m/c is more than capable of locking the front wheel without effort, while most of my braking requires only two fingers at the lever.

Ate: the first radial calipers!

[quote="Chuey"]The turn signal switch is fine. I can't believe that anybody would be all that bothered by it. And, I do find the way you turn the switch to be logical. You flip it up for a left turn, the same direction you would turn a car steering wheel, and down for right. The one and only way it is a problem is if you have multiple bikes and your mind doesn't switch back and forth easily.[quote]

Chuey, by year ('74) and your description you don't have the switches people find illogical. That was changed in '75.

pkboxer wrote: Chuey, by year ('74) and your description you don't have the switches people find illogical. That was changed in '75.

IIRC. the /5 style switchgear fitted to the 1974 /6 model used the same up/down setup as the later /6 & /7 switchgear. I agree with Chuey, I've never had an issue with the system.

[quote="Duane Ausherman"][quote="Zombie Master"]The single disc brake on the 74 seemed a big improvement over the old drums. quote]

ZM, you are about the last person on earth who thinks that the 74 disc was better than the drum on the /5. Even the BMW literature showed it stopped in a longer distance.

Worked better for me. Maybe I just figured out how to set it up. Maybe it was the stainless brake line.