http://xiurdi.com/works/embrague-hidraulico-hebo/

This, when it's properly adapted, could work on drumbrakes also, I think...

Quite possibly but here in the UK, I don't know about the rest of the world, most bikes that are fitted with drum brakes are either P65 or Twinshocks and hydraulic controls are ruled illegal modifications with most clubs.

Yes it goes beyond "spirit of the class " But it would probably not work much better than good drums and shoes set up correctly , with a stout cable on the front ! , Most rears are rod actuated ... So I don't think you would gain much except some weight ...

Glenn

BTW same restriction applies to the clutch.

at least one bike locally is being 'tried' with such modifications to clarify the difference/ validity/ improvements

Not that I have plans in that direction but I think it will be a easyer way to get a good rear brake when the brake hub is on the left side and the brake pedal on the right.

As stated in the discription, you will also have a constant performance without the trouble of greasing or cleaning brake- or clutch cables, poor cable routing etc.

Hydraulic actuated drum brakes are common in cars and the benefits are undeniable I think.

But as O. T. Fanatic says, rules are rules, and for good reasons

Good thing if you are 'girl pants'...

As to using it in a clutch application, really cannot see why it cannot be used to aid ageing wrists and hands. Where is the difference when looking at all the other accepted mods.

As to using it in a clutch application, really cannot see why it cannot be used to aid ageing wrists and hands. Where is the difference when looking at all the other accepted mods.

The difference is most clubs rules clearly state no hydraulic controls. The other "mods" whatever they are assuming the bikes in question are not deemed illegal must therefore be inline with the relevant clubs rules. That's simple isn't it ?

Had a couple turn up at our trial in the past just put them down as ineligible machine on the results. Again simple really.

I think we have so far avoided rules against hydraulic brakes or clutches on Twinshock or P-65 in Australia, yet there are very few hydraulic clutches in use and no hydraulic brakes that I have seen.

Clutch:

Main reason for not using one on a clutch is that most P65 and Twinshock engines still have a mechanical linkage/mechanism/gizmo of some sort between the cable and the pressure plate, so the only improvement with the Hebo comes from eliminating the cable friction, and if you set the clutch up cleverly there is only a low load on the cable to create friction in the first place. When people test my (cable operated) Bultaco and Yamaha twinshock clutches for lever pull load they usually tell me that they are as light or lighter than their Beta, Sherco or whatever modern bike clutch. An exception to the linkage friction issue on old bikes is the Bultaco, because a hydraulic cylinder can easily be fitted co-axially with the pushrod, which means it then has as little friction as a modern bike setup.

Brakes:

The reason why setups like the Hebo shown are not used on trials bike drum brakes is that by far the greatest source of friction in the brake mechanism is the cam shaft to bushing and cam to cam followers. In a car with hydraulic drum brakes, the hydraulic cylinders act directly on the brake shoes, so there is no frictional loss. If you could find a way to fit tiny hydraulic cylinders inside the brake drum on a classic trials bike, you may get a better action than with a cable/cam system.

i have used rear hydralic system on a few bikes over the years worked great on a triumph mettise trials outfit back in the eighties and have just modified a panther rear drum this seems fine as well , it does make for a very efficent self adjusting brake. aa will.