Early (1974 / 75) late (post 1977) brake calliper compatability

[DaveO]

Hi there

I have a 1975 xs650B with a Nissin 13/16" bore front master cylinder. There's a previous thread from about two years ago discussing this. Seems like the 13/16" rebuild kits aren't available.

So I've found a source for complete new master cylinders and I'm happy with this. I plan to use 11, 12, 13, or 14mm master. (13/16" is 21.5mm which I reckon is large for twin discs so it will be massive for the single disc setup I plan to move to. So tossing the old one in the parts bin is no disaster and hopefully will be an improvement.)

I am going to rebuild one of the two callipers. I have two to cannibalise and they can be swapped over by exchanging the pillar for the bolt (so "handing" isn't a problem). I have seal kits so no problem here. (Thank you the PO.)

My question is - I can get the later single piston brake calliper from yambits.co.uk If I use one of these (new or one to rebuild) can I use a single piece brake line instead of the multipart standard lines? And is it going to fit on the fork lower? It would save me money and hassle and it would all look neater. (The junction come brake switch will be surplus in any case.)

http://yambits.co.uk/xs650-brake-caliper-left-hand-p-38996.html

but is this compatible with the fork lower, disk etc..

boats.net shows the two lowers with similar part numbers 477-23101-53-00 and
2F0-23101-00-00.

Also if anyone can re-assure me that RH, LH and "not handed", fitted in advance of the fork, and fitted to the rear of the fork I'm going to be able to make all this fit that would be great. Someone MUST have been here before.

Dave

Edit - This is the previous post from PaulXR http://www.xs650.com/threads/1975-uk-euro-spec-twin-disc-master-cylinder-help.40054/

 

[5twins]

The later caliper will not fit on your '75 fork leg, the caliper mounting bolt spacing differs. Your old calipers are two piston type, and you had two of them. That's why your MC was so large. I think for only one of your calipers, a 5/8" size was used, still a bit large. All the MC's on early bikes seem a bit large. I guess the manufacturers hadn't quite figured that stuff out yet.

The early 2 piston caliper is supposed to work pretty good. Renovate one of yours and, according to this chart, get a 13mm MC .....

 

[DaveO]

Hey 5twins

Thanks very much for the speedy reply. You guys are the 4th emergency service. You've also stopped me from buying the wrong master as I thought 11mm was optimal. I didn't realise that having twin pistons was a factor and have sort of absorbed the general discussion advice on the board.

Dave

 

[gggGary]

Nice chart 5T! 14mm MC's are dirt common and easy to find. Will be a big improvement. Haven't done this set up yet but I'm sure I will one of these days. Never hurts to go to SS lines though that fitting on caliper makes it a bit tricky. If you keep the caliper in front you would either need to find a skinny line or use the stock steel line to clear the fork tube.

 

[DaveO]

Thanks gggGary.

 

[5twins]

Credit for the chart goes to 3M. I got it off his Vintage Brake site. I just labeled the 650 sizes.

 

[650Skull]

SS braided brake line for the 74-76 XS650
http://www.slingshotcycles.com/74-76-XS650-1pc-Stainless-Steel-Braided-Brake-Line_p_122.html

 

[DaveO]

Hey 650skull

That's a great bit of kit. Thanks.

Dave