New Airhead owner - fork question

[Delaplanet]

I’m the proud new owner of a 1978 R100/7. I actually don’t know which variant it is…it has had a mediocre cafe racer build at some point in its life. Almost nothing on the bike works, so I have a lot cut out for me, though it does run and shift gears!

I’m trying to decide if I want to stick with the single, ATE brake or upgrade to dual discs in the front. I just bought a pair of Brembo lower fork sleeves from a dual disc R100. Will these fork sleeves fit on the stock tubes from the 1978 single ATE brake front end?

If I can get these to work, I’ll upgrade brakes and switch to spoked wheels (it currently has Lesters). If not, I’m just going to rebuild/refurbish what’s on there.

Thanks, excited to be part of the club!

Delaplanet
Oakland, CA
USA

[Kurt in S.A.]

Welcome to the forum! What year are the sliders from? Tubes changed diameters at some point. The usual way to go is to add a second fork slider to accept a second ATE caliper...you'd have to find one from an RT or RS or something like that from that period. You'd also have to look into brake lines and maybe a new master cylinder. I can never figure out what diameter of master cylinder is needed once you've added the extra volume. You might want to add a handlebar master cylinder to get rid of the under tank one.

IMO the single ATE can be pretty decent if you understand what you have. There's a way to align the pads to get pretty optimum braking.

Kurt in S.A.

[Delaplanet]

Yep, it’s just pretty hard to find a right hand fork for the second ATE brake.

It seems after measuring that the inner diameter of these brembo fork sleeves is too big - 38.6mm, and the ones that are on there are 36mm

The thing has already been updated with a handlebar reservoir/master cylinder, but the brake is TERRIBLE. I can rebuild the ATE caliper (seems pretty easy) but I want to replace all the hand controls and grips with the Walzwerk stuff - not sure if their master cylinder (designed for dual calipers) will work with the single, ATE. I emailed them…will let you know.

[jagarra]

This may be the way to go, this seller has a good reputation as far as airhead parts. https://www.ebay.com/itm/265292027843?h ... Sw629hLVOB

I have bought a lot of items from him over the years.

[Delaplanet]

Yep, I’m watching it

[Tom H Ca]

Maybe this chart will help:

http://www.vintagebrake.com/mastercylinder.htm

Tom