Early type calipers - are they "handed" ?

[Grewth]

I'm a little confused.
In the UK, Yambits are selling a pattern '72 type caliper, which is no doubt manufactured somewhere in the Far East.
Quality looks good, and their website says that for bikes with twin discs, (like the UK XS650B, and C models), all you have to do is reverse the fixings on one caliper.
Fair enough.
But today I got my hands on an original set of calipers from what I assume was a 650B.
There is a slot machined in for the brake pad tangs.
Machined so it makes the calipers "handed" by my reckoning.
And there's more slots machined in the inner caliper halves.
But they don't align with the outers.
It's occurred to me that someone has swapped around the caliper halves at some point ?
Maybe.
It's been about thirty years since I actually owned a bike with these calipers, my memory has failed me (and I don't think that I ever had to do any work on the brakes)
So have I actually managed to buy a matched pair ?

 

[Grewth]

Just found out the answer to the tang slots aligning.
Found these photos of a dismantled XS2 caliper.
Slots on this caliper align when assembled.

Can't work out why someone would want to reverse the halves.
Would it have something to do with the bleed nipple ports, and moving the calipers behind the fork legs like on the 650C model ?

 

[GLJ]

Can't work out why someone would want to reverse the halves.
Would it have something to do with the bleed nipple ports, and moving the calipers behind the fork legs like on the 650C model ?

Probably mixed them up when rebuilding them. I'm not sure if makes any difference which way the slots go.

 

[Jim]

Slots are water/gunk drains?
Supposed to be down?

 

[GLJ]

Slots are water/gunk drains?
Supposed to be down?

I looked at the 76 parts for the dual disk model and they show the same caliper used on both sides.

 

[Grewth]

I looked at the 76 parts for the dual disk model and they show the same caliper used on both sides.

That's weird.
Because what I've got here isn't the same caliper, they are different.
They appear to be handed to my way of thinking.
Maybe another oversight by the supposedly inscrutable Japanese ?

 

[GLJ]

That's weird.
Because what I've got here isn't the same caliper, they are different.
They appear to be handed to my way of thinking.
Maybe another oversight by the supposedly inscrutable Japanese ?

Couple of things. If you flip the inside/outside calipers in the pic you posted then the slots will line up in each caliper.
It could be when they built them they had a left and right caliper. Then decided when it came to replacement parts it doesn't make any difference.
I can't really see how or why it would make a difference.
I added a second caliper on the 73 front end I'm using on my last build. I just grabbed two out of inventory and rebuilt them. The right has the slot to the back of the bike, the left to the front. They seem to work ok.
It could be on new bikes they wanted both slots to face the rear for aesthetic reasons.

 

[GLJ]

Then again I could be all wet.

 

[Grewth]

Couple of things. If you flip the inside/outside calipers in the pic you posted then the slots will line up in each caliper.
It could be when they built them they had a left and right caliper. Then decided when it came to replacement parts it doesn't make any difference.
I can't really see how or why it would make a difference.
I added a second caliper on the 73 front end I'm using on my last build. I just grabbed two out of inventory and rebuilt them. The right has the slot to the back of the bike, the left to the front. They seem to work ok.
It could be on new bikes they wanted both slots to face the rear for aesthetic reasons.

Probably the latter - aesthetic reasons only.
Well it doesn't seem to really matter greatly so I won't worry about it.
Seems to be a good bit of corrosion around the pistons, so I'll be having fun extracting them shortly.

 

[DogBunny]

Slots are water/gunk drains?
Supposed to be down?

The slots are for the ears on the brake pads. The ears are wear indicators. If the slots are oriented wrong, the ears will rub against the fork tube. You can fix this by shortening the ear.
EDIT: the ear is SUPPOSED to face the fork leg, where it will be less obtrusive.

 

[arcticXS]

I wonder what happened when the calipers were moved to behind the fork sliders, for the 76 model

 

[DogBunny]

They swapped the position of the slots.
If you buy the repop caliper, it has two sets of slots, on either side, so you can put it wherever you need it, left or right fork, in front or behind.

 

[Grewth]

They swapped the position of the slots.
If you buy the repop caliper, it has two sets of slots, on either side, so you can put it wherever you need it, left or right fork, in front or behind.

Thanks for that.
So at least now I'll know if someone is trying to sell me a repop caliper, masquerading as a genuine Yamaha article

 

[Grewth]

I wonder what happened when the calipers were moved to behind the fork sliders, for the 76 model

I haven't ever looked closely at these early calipers, to see exactly how they are constructed.
I'm actually wondering how they bleed the fluid on the '76 bikes, the bleed nipples seem to be in the wrong place.
I can remember reversing the fork legs on my Suzuki GT750, back around 1978 or so (and that makes me feel REALLY old), because all the newer bikes had their calipers mounted behind the fork sliders.
So I had to undo the brake pipes to swap the calipers over.
And then I couldn't manage to bleed the air out of them.
Took a bit of head scratching before I realised that the bleed ports for the single piston calipers were right at the top of the caliper bore when mounted normally.
Moving them behind the sliders had tilted them from vertical by 30° or so, creating an air pocket.
Solution was remove the mounting bolts and sit the calipers facing upright on the discs until I bled all the air out.

 

[650Skull]

I'm a little confused.
In the UK, Yambits are selling a pattern '72 type caliper, which is no doubt manufactured somewhere in the Far East.
Quality looks good, and their website says that for bikes with twin discs, (like the UK XS650B, and C models), all you have to do is reverse the fixings on one caliper.
Fair enough.
But today I got my hands on an original set of calipers from what I assume was a 650B.
There is a slot machined in for the brake pad tangs.
Machined so it makes the calipers "handed" by my reckoning.
And there's more slots machined in the inner caliper halves.
But they don't align with the outers.
It's occurred to me that someone has swapped around the caliper halves at some point ?
Maybe.
It's been about thirty years since I actually owned a bike with these calipers, my memory has failed me (and I don't think that I ever had to do any work on the brakes)
So have I actually managed to buy a matched pair ?
View attachment 328541View attachment 328542

Bit late to the party.....but......yes Yamaha had a left and right for the 34mm caliper for the euro XSB/C. We got them on our C model only. I have a set, will take pics

2 rights or 2 lefts can be used as a pair. As can b seen the brake pad tabs on one will foul. Need to grind a bit of the caliper, (or cut part of the brake tab, away), for the tab to b moved enough to fix. Changing the caliper mounting bolt over to the other side of the calioer, swaping it with the bolt that holds the caliper together

 

[650Skull]

Left and right,