Alternate brake discs

[nb1914]

Hi All,

Are there any alternate brake disc options for a standard setup. The only ones i can find new are 150 to 175 sterling each ! i think the ones off the bike are past being skimmed so was wondering if there are more available alternatives new or second hand.

 

[fredintoon]

Hi All,

Are there any alternate brake disc options for a standard setup. The only ones i can find new are 150 to 175 sterling each ! i think the ones off the bike are past being skimmed so was wondering if there are more available alternatives new or second hand.

Hi nb1914,
if you'd kindly build your XS650's year of manufacture and the country where it was originally sold into your nametag or signature line it'd save us all some posts when you ask technical questions, eh?
If your XS650 has 34mm fork tubes and two piece brake disks AFAIK you are SOL for alternatives.
If your XS650 has 35mm fork tubes and one piece brake disks and it's the Euro-model dual disk the disks from an XS750/850 will fit, as will the rear disk from an XS650.
OTOH if it's a North American model the XS750/850 disks are too small but the XS11 disks are a straight swap.
Some XS11 disks are slotted which will save you the considerable effort involved in drilling the disks full of holes.
Note that ALL XS series disks will bolt up to ANY XS650 disk brake hub but the two piece and one piece disks are dished differently and will not align with the other style of caliper and the smaller disk ain't big enough to fully reach into a larger disk caliper.
Most likely you could find used disks in the list's classifieds and even with transatlantic shipping costs make money on buying new in the UK.

 

[nb1914]

Hi Fredintoon,

I will try to setup the bike information, TBH I'm not sure exactly about the true identity of the bike, the logbook just says Yamaha & 600cc ? the engine block has 650 on it so its probably a frame engine swap somewhere or someone registered the bike incorrectly. some pics below

 

[fredintoon]

Hi nb1914,
The different sized one piece brake disks make me think that your bike started out as a 1980 Special and the frame photo shows that a dreaded PO modified the frame with a BratStyle conversion.
If you can read the frame ID that's letterstamped into the frame steering neck and the engine ID that's letterstamped into the crankcase those will let you check with Skull's XS650 ID post to find out just what you do have.
BTW, the disk photos don't show the brake surfaces to be in too bad of a shape.
Also the disks' new thickness is 6.5mm and the aftermarket disks are only 5mm.
What I'd recommend is to drill those disks full of holes and put them back on the bike.

 

[nb1914]

There is no number on the frame, i know that an owner 3 PO's ago built it as a custom so that will be where the frame conversion comes from and numbers filed off and powder coated over. The engine number 3L1 022032 puts the engine as a XS-SF. It has been registered against the engine number, the frame is in very good condition no rust anywhere but i did have to cut the rear swingarm bolt and sleeve out. Everything else looks standard 1980ish stuff. I had another good look at the discs and i might just squeeze and skim out of them but if i can get alternatives that is good.

 

[retiredgentleman]

Your discs are not too bad. You could save some money if you have access to a drill press. I made up a simple tool and then spun the discs with my drill press. With a little work they will clean up almost like new.
Here's a link:
http://www.xs650.com/threads/homemade-and-unique-tools.37/page-4

 

[nb1914]

Thanks Guys, maybe i have come across too many over enthusiastic MOT testers here in the UK , the discs easily have 6mm plus thickness so i will try to tidy them.

 

[fredintoon]

There is no number on the frame, i know that an owner 3 PO's ago built it as a custom so that will be where the frame conversion comes from and numbers filed off and powder coated over. The engine number 3L1 022032 puts the engine as a XS-SF. It has been registered against the engine number, the frame is in very good condition no rust anywhere but i did have to cut the rear swingarm bolt and sleeve out. Everything else looks standard 1980ish stuff. I had another good look at the discs and i might just squeeze and skim out of them but if i can get alternatives that is good.

Hi nb1914,
I reckoned 1980 because that's the only year I know of that had a disk rear brake.
(edit) Finally remembering that my friend's '79 has a disk rear and then checking Skull's photo array to see that '78SEs, '79SFs, '80SGs & '81SHs all had 'em.
And yes, as posted, your engine's ID sez it came out of an SF.
But as XS650 parts swap from year to year just like LEGO, who knows what year the frame was? (end edit)
Filing the frame number off seems a bit dodgy to me but as the 4th owner since then
the cops can't very well pin it on you, eh?
But unless your disks are in far worse shape that the photos indicate, I still recommend
doing a drill job on them.
I drilled mine with 3/8" holes and a decade later their surfaces have actually improved.
If I'd to do it over I'd have drilled more holes but used a 5/16" drill bit instead.

 

[650Skull]

Looks to be an 80 US Custom model Single front disk. If replacing the disk, (don't need to if following RG's comment), take note the Euro double front disk models.have the smaller rotor as per the rear on your bike.

80 US Custom from 3L1-020101 to 3L1-04000

 

[fredintoon]

Hi Skull,
OK then, single large disk is North American and dual small disk is Euro.
Was there a market area that had dual large disks as stock or were they all retrofitted by amateurs?

 

[650Skull]

Fred,
The US Custom was the, Special, made for the Euro market. These bikes had the same set up as the US bikes, single disk front brake.

Euro standard was made up to 82, well the same as the Canadian Specials, they sold the same model a year later after production stopped. This model has the twin disk front end and these are the smaller rotor disk model, with the mount on the fork lower moved lower on the front fork so the caliper will match the small rotor.

Oceania, Aus/NZ has the large rotor twin disk front brake as a factory sold model. The twin disk started in 76 and carried right through to 81