Topic: structural question - fork swap with the dreaded drum brake.

[greenjeans]

I know this makes absolutely no sense but...   

I have a giant 4LS drum brake (been hoarding it for years) that I want to use on my current toy - (73 CB750K)   Not much trouble there.   My problem is:   Now I want to run that brake with a modern inverted fork off a GSX or CBR what ever ends up being easier.

The drum brake requires a stay for each side.   No problem on the older style forks - you'd just use the fender/brace mounts.

Since I'd be using the inverted forks, the only places to mount the stays would be on the caliper mounts.    Again, i don't really see too much of an issue there - I could be wrong.    My concern would be if the mounts for the calibers would be strong enough for the drum stays.   The calipers have 2 mounting holes, where the drum stay would only require one.   I guess I could make a stay that used both.

And if that isn't enough, I'd like to remove the excess material from the lower fork as well to clean it up.   Most of them look like the are a cast piece then machined.  Would that be a bad idea ?

And finally, this isn't going to be a race bike or anything.   I've finally accumulated enough bits and pieces to build myself something I can keep for a while.

I'll be shopping for a fork this weekend.

[FunJimmy]

Interesting concept.

I'd be surprised if the drum brake could exert the forces required to stress a modern USD fork.
Especially on day to day riding conditions 

[SOHC4 Cafe Racer Fan]

Interesting indeed.  Most guys change to the modern front end and go modern with the brakes, too.  Your combo is a bit of a mindbender:  better handling but older braking (a good twin leading shoe probably beats a stock un-rebuilt disc though!). 

[greenjeans]

Purely aethetics.  I plan on stripping the anodized finish off the forks so they don't immediately give things away.  Want to keep a vintage race-bike "look" but with some subtle changes so it's not as easy to recognize things.   At the risk of saying it...industrial.

[Flying J]

I like it. Get it done.

[Stev-o]

Love the look of frt drums...

[fastbroshi]

I think it'd be easier to do with a USD fork that doesn't use radial mount brakes.  Some member here just picked up a rough ZX-7 that he's going to part out, I'm pretty sure those had mounts you could use.  I think the member's name is Dmitri something.

[lucky]

It is the same force.

Drum or disc.

Just make sure you make a good link or plate.
It is done all the time.

[FunJimmy]

It is the same force.

Drum or disc.

Just make sure you make a good link or plate.
It is done all the time.

Not if the drum can't stop the bike in as short a distance as a disc.

[lucky]

It is the same force.

Drum or disc.

Just make sure you make a good link or plate.
It is done all the time.

Some drum brakes are better than the disc brake. They have more swept area and some have multiple shoes being actuated.

Not if the drum can't stop the bike in as short a distance as a disc.

Some drum brakes are better than the disc brake. They have more swept area and some have multiple shoes being actuated.

[FunJimmy]

Some drum brakes are better than the disc brake. They have more swept area and some have multiple shoes being actuated.

That may be true of disc vs drum brakes of a similar vintage, but your earlier statement was directed at my comment below.

I'd be surprised if the drum brake could exert the forces required to stress a modern USD fork.

 

"forces required to stress a modern USD fork" being of importantance.

[greenjeans]

When you see the braking surface of this monster, you'll understand.   It won't be as nice as a modern 4-piston caliper brake, but it will stop this beast as good or better than the original.   A lot of the vintage race guys use this exact brake.  (It's off the 72 Suzuki GT750)

Still searching for a front end at a somewhat reasonable price.

[Toxic]

and those GT750 brakes are getting hard to find and cost a pretty penny.

Lucky you.