R80 brakes appeal

[havelockjohn]

Right, i have an R80 which the previous owner did all the hard work(and money) eg, modified forks and yokes, 1000cc conversion and a master cylinder conversion, you know the handlebar mounted one.
Now, the front brakes are hopeless. As a mechanic, the first thing i did was change fluid and bleed them to no benefit.
It's got those swively single pot calipers(which are free, pistons working too) and PFM cast discs.
I find it hard to believe that the brakes can be that bad.
I have another R80 in standard format, though i'm unable to compare at the moment, i dont think its anywhere as near as bad.
Could it be that master cyl is not up to the job. Are better callipers on the market.
Please help, i'm taking it round Scotland soon and i dont have enough underpants for the trip

Cheers

John

 

[ghiribizzo]

Are the pads ok? Plus the ATE calipers need the eccentric cam pivot pins adjusted so that the fixed pad is lined up with the disc. Haynes/Clymer will help if unsure...
Mebbe master cylinder piston size is not appropriate - but they're not Brembos...

 

[Rob Farmer]

It sounds as though something's amiss. I had the same setup on a bike and thought the brakes were fine and certainly no worse than the Brembo setup on my R100.

What piston size is the master cylinder? Anything stamped on the ATE callipers and has it got a splitter under the tank?

Have you tried new brake pads and as ghiribizzo mentioned are the callipers adjusted so that the pads are parallel to the disc.

 

[Beemerboff]

I have twin CI disks and a 12mm MC and they work fine, once the rust is off the disks and the pads, so give them a decent workout and see if that helps
The pads may also have been contaminated with oil or something, they never seem to work right after, so new pads may be the go, but get any rust off with the old ones first.
According to my OEM handbook the pins should turn easily enough that a good hard squeeze of the brakes should line the pads up - doesnt seem to work that way but that is what to aim for,

 

[havelockjohn]

brake appeal

Thanks for the suggetions.
The pin sounds very likely thinkin about it.
I noticed a small amount of sidewards force on the disc, which could account for the spongey feel.
Will check it out tomorrow.

Thanks again